Re: [RE-wrenches] Remote battery disconnects

[Christopher Warfel via RE-wrenches]

Thanks for doing this.  Chris

On 2/1/2023 4:49 PM, Brian Mehalic via RE-wrenches wrote:
Most firefighters are not electrical engineers; nor are most insurance 
agents. However both of those groups are stakeholders with influence 
over codes and standards. Some may say too much influence, but the 
fact of the matter is that code making is a group/consensus process, 
and very often none of the groups get exactly what they want (in fact 
sometimes a group accepts exactly what it doesn't want to leverage 
that for something they do; yes it often smacks of politics). I would 
appeal to y'all to submit a proposal for the 2026 NEC® - they are due 
by September of this year. Better yet would be to circulate language 
that this, or some other, group can work on, agree on, write a solid 
technical justification for, and sign their names to and submit - the 
more stakeholders that support a proposal the more weight it has.


It seems that the PV Industry Forum, or another similar body, may 
again begin work to develop PV and storage industry 
stakeholder-consensus PIs to submit; in the past this was a very 
successful endeavor. I'll post on this list if and when that happens 
so that anyone that is interested can get involved, but don't let that 
possibility keep you from submitting any PIs on your own.


Maybe in the meantime, a control system that shuts off the PV, and 
then the batteries, would be worth designing.


Brian Mehalic




On Wed, Feb 1, 2023 at 2:10 PM James Jefferson Jarvis via RE-wrenches 
 wrote:




On 2/1/2023 2:58 PM, Starlight via RE-wrenches wrote:
> Have you (or any) installed surge suppression on the PV input
side to
> clamp the open circuit voltage surge?

That's not where the issue is and isn't really a solution. As I
explained in my previous e-mail, the issue is the open circuit on the
output leaves no where for the energy in the MPPT controllers
inductor
to go and the only option is for the voltage to rise until it finds
somewhere to go.

Surge suppressors, such as sold by Midnite Solar, are nothing more
than
Metal Oxide Varistors. Or in the case of Delta, they are pieces of
wire
in sand. They require large rise in voltage before they conduct.

MOVs are sometimes found on the battery side of inverters and charge
controllers, but their clamp time and voltage before clamping
requires
additional circuitry that works faster to protect fragile
semiconductors.


If you are proposing using a surge supressor to regulate the
voltage of
an island between a charge controller and an inverter when the
battery
is disconnected, that's also a no go. Once the MOV clamps, it stays
clamped until voltage goes essentially to zero or until it blows up.
It's not a regulator.

-

To further stir the pot, it is definitely possible to design
electronics
that can deal with load dumps and survive most anything. Aerospace
electronics come pretty close. But all that costs money and takes
space
to do. Are we comfortable with requiring $16,000 charge
controllers so
they can handle load dumps reliably from a poorly thought out NEC
requirement? I think the fossil fuel industry would be very happy
with
the cost of renewable energy electronics being an order of magnitude
more expensive.




>
> Larry Crutcher
> Starlight Solar Power Systems
>
>
>
> On Feb 1, 2023, at 1:23 PM, William Bryce via RE-wrenches
>  > wrote:
>
> I can also backup what Jim has said, and have seen the same gear
> destroyed by removing the battery abruptly when the controller
is under
> heavy load. They can die, and sometimes die spectacularly.
>
> Have seen SolArk inverters integrated MPPT controllers blow up when
> lithium battery BMS disconnects. Not a field fixable issue.
>
> Just flip off the breaker when the solar is working hard and and
the
> SolArk will give up the smoke.
>
> Like I originally said, it’s the non talked about issue that is
a big
> issue depending on what gear your using.
>
> On Wed, Feb 1, 2023 at 2:49 PM James Jefferson Jarvis via
RE-wrenches
>  > wrote:
>
>
>
>     On 2/1/2023 12:25 PM, Alex MeVay via RE-wrenches wrote:
>      > Although our controllers are probably smaller than what
you would be
>      > considering in this discussion, surviving a load dump
(suddenly
>      > disconnected battery) is an engineering requirement for
us, and
>     likely
>      > would be for other responsible MFG's on this list
(boB?).  The charge
>      > controller can either handle full input voltage on the
output, or
>      > there is a comparator that will shut the controller down
instantly
>      > when the output 

Re: [RE-wrenches] Remote battery disconnects

[jay via RE-wrenches]

As 480.7(B) says single and double homes, that going with the mike holt literal 
interpretation to me says that even if you have a remote power shed it would 
still require the remote disconnect. As that section doesn’t say that the power 
system is in the house or not. 

(A) doesn’t apply as the batteries are sub 60v
(C) doesn’t apply because its a 48v battery


However, as we’ve seen in the past with NEC requirements that there was no UL 
part for:  GFCI for charge controllers, or RS as just 2 examples, that gives an 
out because there is no part to use.  
I’d say its a perfect new part for midnite to make.

William’s point about making one, sure can do that but then the AHJ will ask 
for the UL listing.  


I still have the question as to what is the design of the battery conductor 
disconnect? What is it trying to protect?  Sure its the battery conductors, but 
why?
If the goal is to make sure its safe for the fire personal to cut through 
walls, ok then they could be cutting into the battery just as easily as the 
conductors. 
If its to shut off power to the house, then it fails on that one.  Power goes 
out and the back up generator starts for just one example.  
Which puts us back to the main AC disconnect which is going to shut off all the 
AC power in the house. 
Rapid shut down already has requirements for house mounted systems which takes 
care of the +60v DC conductors although is not required for separate power 
sheds. 

Thanks

jay








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Re: [RE-wrenches] Remote battery disconnects

[Jason Szumlanski via RE-wrenches]

 watching the whole time. The
>>> system was shut down when we arrived, then the PV breaker was turned on,
>>> then the battery breaker was turned on momentarily, then the battery
>>> breaker was shut back off. The charge controller went into the startup
>>> procedure, and it went to sweep the IV curve, and as it did, it was pumping
>>> all that power into it's capacitors and it had nowhere to go. I watched the
>>> voltage on the screen skyrocket and then it suddenly burned out with a
>>> small pop. The charge controller was stuck in the startup, and it wasn't
>>> able to stop producing current. If the battery breaker had been left on
>>> while it stabilized, then it was shut off, it would have been fine. So if
>>> you turn on the system, don't suddenly trip the disconnect until it has
>>> been on for a minute.
>>>
>>> Also, inverters have capacitors that are much, much, much larger than
>>> the capacitors in the charge controller, so when a main battery disconnect
>>> is thrown and the charge controller is connected to an inverter
>>>
>>> Now, I completely avoid cheap charge controllers (Amazon charge
>>> controllers, etc.). I don't touch them with a 10 foot pole. I have seen so
>>> many DIYers reject my advice, install a cheap one, and have it burn up
>>> within a couple of years or less. I wouldn't be surprised if suddenly
>>> disconnecting the battery would be a likely cause of failure in these cases.
>>>
>>> Also, with any quality brand, if this somehow did happen, they'll still
>>> honor it under their warranty, and this will be a rare occurrence.
>>>
>>> William said that SolArk can't handle having the breaker thrown while
>>> it's charging the battery, so there are definitely exceptions. I've never
>>> used SolArk, but with everything else I've heard about them, I'm really not
>>> too surprised. I'm not faulting SolArk, and I'm not a SolArk hater, I just
>>> know that their hands are somewhat bound by the real manufacturer who
>>> is in China. SolArk only has limited control of their product. But as
>>> boB from MidNite pointed out, it all equipment can and should be designed
>>> with this in mind. Fuses will blow, breakers will get tripped, and any
>>> quality manufacturer is going to take that into consideration. They can
>>> take the low road and simply plan on replacing some under warranty, or the
>>> can engineer the product to withstand it.
>>>
>>> One last note about codes, there are some codes that I hate and try to
>>> avoid, but I also personally know 2 or 3 of the people on the code panels.
>>> There are some people on the code panels who are not kind to our industry,
>>> but there are a couple of people on those panels who really are our
>>> advocates. If someone is on the code panel, they are actually limited in
>>> how they can suggest new changes to the codes, they can only promote public
>>> inputs that are submitted by people like us, so even if it feels like a
>>> waist of time, it really is important that we all submit our ideas and
>>> thoughts through the official pathways so that our advocates who really
>>> want to promote our best interests have something they can leverage for us.
>>> To those here who do help with the codes and help to advocate for us, THANK
>>> YOU SO MUCH!!!
>>>
>>> Thanks,
>>> Kienan
>>>
>>>
>>> *Green-Go Solar Distribution LLC Maxfield Solar LLC (installation and
>>> consulting company) *
>>> *maxfieldso...@hotmail.com*
>>> *(801) 631-5584(Cell)*
>>> --
>>> *From:* RE-wrenches  on
>>> behalf of bob--- via RE-wrenches 
>>> *Sent:* Wednesday, February 1, 2023 8:06 PM
>>> *To:* RE-wrenches 
>>> *Cc:* b...@midnitesolar.com 
>>> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>>>
>>>
>>>  SPDs or (MOVs) on the PV input side of a charge controller are not
>>> wired to snub excessive PV voltage.
>>>
>>> They are wired from PV+ to GND and the other from PV- to GND and only
>>> the two in series, at double the
>>> MOV clamp voltage would have any effect on clamping the PV+/PV-
>>> voltage.
>>> SPDs are wired to keep the charge controller's insulation system to
>>> below the Hi-Pot voltage the unit is
>>> tested with.  i.e.  They are wired for common-mode and not
>>> differential.  That voltage is much higher
>>> than maximum 

Re: [RE-wrenches] Remote battery disconnects

[August Goers via RE-wrenches]

rter
>>
>> Now, I completely avoid cheap charge controllers (Amazon charge
>> controllers, etc.). I don't touch them with a 10 foot pole. I have seen so
>> many DIYers reject my advice, install a cheap one, and have it burn up
>> within a couple of years or less. I wouldn't be surprised if suddenly
>> disconnecting the battery would be a likely cause of failure in these cases.
>>
>> Also, with any quality brand, if this somehow did happen, they'll still
>> honor it under their warranty, and this will be a rare occurrence.
>>
>> William said that SolArk can't handle having the breaker thrown while
>> it's charging the battery, so there are definitely exceptions. I've never
>> used SolArk, but with everything else I've heard about them, I'm really not
>> too surprised. I'm not faulting SolArk, and I'm not a SolArk hater, I just
>> know that their hands are somewhat bound by the real manufacturer who is
>> in China. SolArk only has limited control of their product. But as boB
>> from MidNite pointed out, it all equipment can and should be designed with
>> this in mind. Fuses will blow, breakers will get tripped, and any quality
>> manufacturer is going to take that into consideration. They can take the
>> low road and simply plan on replacing some under warranty, or the can
>> engineer the product to withstand it.
>>
>> One last note about codes, there are some codes that I hate and try to
>> avoid, but I also personally know 2 or 3 of the people on the code panels.
>> There are some people on the code panels who are not kind to our industry,
>> but there are a couple of people on those panels who really are our
>> advocates. If someone is on the code panel, they are actually limited in
>> how they can suggest new changes to the codes, they can only promote public
>> inputs that are submitted by people like us, so even if it feels like a
>> waist of time, it really is important that we all submit our ideas and
>> thoughts through the official pathways so that our advocates who really
>> want to promote our best interests have something they can leverage for us.
>> To those here who do help with the codes and help to advocate for us, THANK
>> YOU SO MUCH!!!
>>
>> Thanks,
>> Kienan
>>
>>
>> *Green-Go Solar Distribution LLC Maxfield Solar LLC (installation and
>> consulting company) *
>> *maxfieldso...@hotmail.com*
>> *(801) 631-5584(Cell)*
>> --
>> *From:* RE-wrenches  on
>> behalf of bob--- via RE-wrenches 
>> *Sent:* Wednesday, February 1, 2023 8:06 PM
>> *To:* RE-wrenches 
>> *Cc:* b...@midnitesolar.com 
>> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>>
>>
>>  SPDs or (MOVs) on the PV input side of a charge controller are not wired
>> to snub excessive PV voltage.
>>
>> They are wired from PV+ to GND and the other from PV- to GND and only the
>> two in series, at double the
>> MOV clamp voltage would have any effect on clamping the PV+/PV- voltage.
>> SPDs are wired to keep the charge controller's insulation system to below
>> the Hi-Pot voltage the unit is
>> tested with.  i.e.  They are wired for common-mode and not differential.
>> That voltage is much higher
>> than maximum controller or inverter input voltage.
>>
>> What *IS* in place that might help limit PV voltage is the PV array
>> itself.  Any PV voltage that would try go
>> go above the array's  Voc  would be clamped across the array.  This would
>> be during the day or at night and
>> of course that Voc is determined mainly by PV cell temperature.  Solar
>> panels are just a bunch of diodes
>> in series so will be forward-biased when Voc is exceeded by an inverter
>> or charge controller.
>>   PV modules make great space heaters and can even melt snow, ya know. 
>>
>> As for charge controllers blowing up when charging hard and then
>> disconnecting,  I am very anal in
>> designing in safe guards to keep this from happening on the MidNite
>> Classic at least.  That was done
>> several years ago now.
>>
>> But even then, electronics, especially power  electronics, break once in
>> a while and it is sometimes very
>> hard to know why it happened.
>>
>> With our new HV MPPT controllers,  their E-Panels also include
>> remote-trip PV breakers, triggered by the controller's
>> hardware in order to reduce   battery side  over-voltage in case
>> something goes wrong.
>>
>> So, I understand that we have a remote battery disconnect device
>> basically done but have held off due t

Re: [RE-wrenches] Remote battery disconnects

[Jason Szumlanski via RE-wrenches]

us.
> To those here who do help with the codes and help to advocate for us, THANK
> YOU SO MUCH!!!
>
> Thanks,
> Kienan
>
>
> *Green-Go Solar Distribution LLC Maxfield Solar LLC (installation and
> consulting company) *
> *maxfieldso...@hotmail.com*
> *(801) 631-5584(Cell)*
> --
> *From:* RE-wrenches  on behalf
> of bob--- via RE-wrenches 
> *Sent:* Wednesday, February 1, 2023 8:06 PM
> *To:* RE-wrenches 
> *Cc:* b...@midnitesolar.com 
> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>
>
>  SPDs or (MOVs) on the PV input side of a charge controller are not wired
> to snub excessive PV voltage.
>
> They are wired from PV+ to GND and the other from PV- to GND and only the
> two in series, at double the
> MOV clamp voltage would have any effect on clamping the PV+/PV- voltage.
> SPDs are wired to keep the charge controller's insulation system to below
> the Hi-Pot voltage the unit is
> tested with.  i.e.  They are wired for common-mode and not differential.
> That voltage is much higher
> than maximum controller or inverter input voltage.
>
> What *IS* in place that might help limit PV voltage is the PV array
> itself.  Any PV voltage that would try go
> go above the array's  Voc  would be clamped across the array.  This would
> be during the day or at night and
> of course that Voc is determined mainly by PV cell temperature.  Solar
> panels are just a bunch of diodes
> in series so will be forward-biased when Voc is exceeded by an inverter or
> charge controller.
>   PV modules make great space heaters and can even melt snow, ya know. 
>
> As for charge controllers blowing up when charging hard and then
> disconnecting,  I am very anal in
> designing in safe guards to keep this from happening on the MidNite
> Classic at least.  That was done
> several years ago now.
>
> But even then, electronics, especially power  electronics, break once in a
> while and it is sometimes very
> hard to know why it happened.
>
> With our new HV MPPT controllers,  their E-Panels also include
> remote-trip PV breakers, triggered by the controller's
> hardware in order to reduce   battery side  over-voltage in case something
> goes wrong.
>
> So, I understand that we have a remote battery disconnect device basically
> done but have held off due to
> not knowing how important it would actually be.  300 amps from an external
> switch closure or open.
> Our older BD module basically went away with the bird house and bird next
> shut down system.
>
> There are NEC requirements that are not enforced and some installers
> don't  worry about including,
> but from this discussion, it sounds like this battery disconnect better be
> finished sooner than later.
>
> Now we know.  Thanks !
>
> boB  MidNite Solar
>
>
>
>
> On 2/1/2023 2:49 PM, Brian Mehalic via RE-wrenches wrote:
>
> Most firefighters are not electrical engineers; nor are most insurance
> agents. However both of those groups are stakeholders with influence over
> codes and standards. Some may say too much influence, but the fact of the
> matter is that code making is a group/consensus process, and very often
> none of the groups get exactly what they want (in fact sometimes a group
> accepts exactly what it doesn't want to leverage that for something they
> do; yes it often smacks of politics). I would appeal to y'all to submit a
> proposal for the 2026 NEC® - they are due by September of this year. Better
> yet would be to circulate language that this, or some other, group can work
> on, agree on, write a solid technical justification for, and sign their
> names to and submit - the more stakeholders that support a proposal the
> more weight it has.
>
> It seems that the PV Industry Forum, or another similar body, may again
> begin work to develop PV and storage industry stakeholder-consensus PIs to
> submit; in the past this was a very successful endeavor. I'll post on this
> list if and when that happens so that anyone that is interested can get
> involved, but don't let that possibility keep you from submitting any PIs
> on your own.
>
> Maybe in the meantime, a control system that shuts off the PV, and then
> the batteries, would be worth designing.
>
> Brian Mehalic
>
>
>
>
> On Wed, Feb 1, 2023 at 2:10 PM James Jefferson Jarvis via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>
>
> On 2/1/2023 2:58 PM, Starlight via RE-wrenches wrote:
> > Have you (or any) installed surge suppression on the PV input side to
> > clamp the open circuit voltage surge?
>
> That's not where the issue is and isn't really a solution. As I
> explained in my previous e-mail, the issue is 

Re: [RE-wrenches] Remote battery disconnects

[William Miller via RE-wrenches]

Kieran:

You’ve got me confused with someone else. I do not pretend to know anything
about Sol-arc. ( I do know if I was inventing electrical equipment I would
not put “arc” in the name.)

Wm

On Thu, Feb 2, 2023 at 3:53 PM Kienan Maxfield via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

>
>
> William said that SolArk can't handle having the breaker thrown while it's
> charging the battery, so there are definitely exceptions. I've never used
>
-- 

William Miller
Miller Solar.com
895-438-5600
www.millersolar.com
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Re: [RE-wrenches] Remote battery disconnects

[Kienan Maxfield via RE-wrenches]

Hello all,

I have been an off-grid specialist for 12 years now, and I have never seen or 
heard of a charge controller blowing itself up when it was disconnected from 
the battery while it was in steady state. What I mean is that if it's in bulk 
mode, or absorb mode, or float mode, and the battery disconnect is suddenly 
opened, nothing has ever happened. And this actually has happened a lot of 
times in my career. Most of my clients have a DIY attitude, so if they think 
something is wrong, they'll start flipping breakers off randomly until they 
have shut everything down in order to "reset" the system, and then they turn it 
all back on, and if the problem persists, they feel like they've tried 
something, so then they call. I've had helpers who just can't remember which 
breaker to shut off first. Since I've never seen or heard of an actual case 
where this happened, I don't worry about it to much.

I have seen something similar blow up an Outback FM80 once. The charge 
controller was 7 years old at the time. I was watching the whole time. The 
system was shut down when we arrived, then the PV breaker was turned on, then 
the battery breaker was turned on momentarily, then the battery breaker was 
shut back off. The charge controller went into the startup procedure, and it 
went to sweep the IV curve, and as it did, it was pumping all that power into 
it's capacitors and it had nowhere to go. I watched the voltage on the screen 
skyrocket and then it suddenly burned out with a small pop. The charge 
controller was stuck in the startup, and it wasn't able to stop producing 
current. If the battery breaker had been left on while it stabilized, then it 
was shut off, it would have been fine. So if you turn on the system, don't 
suddenly trip the disconnect until it has been on for a minute.

Also, inverters have capacitors that are much, much, much larger than the 
capacitors in the charge controller, so when a main battery disconnect is 
thrown and the charge controller is connected to an inverter

Now, I completely avoid cheap charge controllers (Amazon charge controllers, 
etc.). I don't touch them with a 10 foot pole. I have seen so many DIYers 
reject my advice, install a cheap one, and have it burn up within a couple of 
years or less. I wouldn't be surprised if suddenly disconnecting the battery 
would be a likely cause of failure in these cases.

Also, with any quality brand, if this somehow did happen, they'll still honor 
it under their warranty, and this will be a rare occurrence.

William said that SolArk can't handle having the breaker thrown while it's 
charging the battery, so there are definitely exceptions. I've never used 
SolArk, but with everything else I've heard about them, I'm really not too 
surprised. I'm not faulting SolArk, and I'm not a SolArk hater, I just know 
that their hands are somewhat bound by the real manufacturer who is in China. 
SolArk only has limited control of their product. But as boB from MidNite 
pointed out, it all equipment can and should be designed with this in mind. 
Fuses will blow, breakers will get tripped, and any quality manufacturer is 
going to take that into consideration. They can take the low road and simply 
plan on replacing some under warranty, or the can engineer the product to 
withstand it.

One last note about codes, there are some codes that I hate and try to avoid, 
but I also personally know 2 or 3 of the people on the code panels. There are 
some people on the code panels who are not kind to our industry, but there are 
a couple of people on those panels who really are our advocates. If someone is 
on the code panel, they are actually limited in how they can suggest new 
changes to the codes, they can only promote public inputs that are submitted by 
people like us, so even if it feels like a waist of time, it really is 
important that we all submit our ideas and thoughts through the official 
pathways so that our advocates who really want to promote our best interests 
have something they can leverage for us. To those here who do help with the 
codes and help to advocate for us, THANK YOU SO MUCH!!!

Thanks,
Kienan


Green-Go Solar Distribution LLC
Maxfield Solar LLC (installation and consulting company)
maxfieldso...@hotmail.com
(801) 631-5584(Cell)

From: RE-wrenches  on behalf of 
bob--- via RE-wrenches 
Sent: Wednesday, February 1, 2023 8:06 PM
To: RE-wrenches 
Cc: b...@midnitesolar.com 
Subject: Re: [RE-wrenches] Remote battery disconnects


 SPDs or (MOVs) on the PV input side of a charge controller are not wired to 
snub excessive PV voltage.

They are wired from PV+ to GND and the other from PV- to GND and only the two 
in series, at double the
MOV clamp voltage would have any effect on clamping the PV+/PV- voltage.
SPDs are wired to keep the charge controller's insulation system to below the 
Hi-Pot voltage the unit is
tested with.  i.e.  They are wired for common-mode and not di

Re: [RE-wrenches] Remote battery disconnects

[bob--- via RE-wrenches]

 SPDs or (MOVs) on the PV input side of a charge controller are not 
wired to snub excessive PV voltage.


They are wired from PV+ to GND and the other from PV- to GND and only 
the two in series, at double the

MOV clamp voltage would have any effect on clamping the PV+/PV- voltage.
SPDs are wired to keep the charge controller's insulation system to 
below the Hi-Pot voltage the unit is
tested with.  i.e.  They are wired for common-mode and not 
differential.  That voltage is much higher

than maximum controller or inverter input voltage.

What *IS* in place that might help limit PV voltage is the PV array 
itself.  Any PV voltage that would try go
go above the array's  Voc  would be clamped across the array.  This 
would be during the day or at night and
of course that Voc is determined mainly by PV cell temperature. Solar 
panels are just a bunch of diodes
in series so will be forward-biased when Voc is exceeded by an inverter 
or charge controller.

  PV modules make great space heaters and can even melt snow, ya know. 

As for charge controllers blowing up when charging hard and then 
disconnecting,  I am very anal in
designing in safe guards to keep this from happening on the MidNite 
Classic at least.  That was done

several years ago now.

But even then, electronics, especially power  electronics, break once in 
a while and it is sometimes very

hard to know why it happened.

With our new HV MPPT controllers,  their E-Panels also include 
remote-trip PV breakers, triggered by the controller's
hardware in order to reduce   battery side  over-voltage in case 
something goes wrong.


So, I understand that we have a remote battery disconnect device 
basically done but have held off due to
not knowing how important it would actually be.  300 amps from an 
external switch closure or open.
Our older BD module basically went away with the bird house and bird 
next shut down system.


There are NEC requirements that are not enforced and some installers 
don't  worry about including,
but from this discussion, it sounds like this battery disconnect better 
be finished sooner than later.


Now we know.  Thanks !

boB  MidNite Solar




On 2/1/2023 2:49 PM, Brian Mehalic via RE-wrenches wrote:
Most firefighters are not electrical engineers; nor are most insurance 
agents. However both of those groups are stakeholders with influence 
over codes and standards. Some may say too much influence, but the 
fact of the matter is that code making is a group/consensus process, 
and very often none of the groups get exactly what they want (in fact 
sometimes a group accepts exactly what it doesn't want to leverage 
that for something they do; yes it often smacks of politics). I would 
appeal to y'all to submit a proposal for the 2026 NEC® - they are due 
by September of this year. Better yet would be to circulate language 
that this, or some other, group can work on, agree on, write a solid 
technical justification for, and sign their names to and submit - the 
more stakeholders that support a proposal the more weight it has.


It seems that the PV Industry Forum, or another similar body, may 
again begin work to develop PV and storage industry 
stakeholder-consensus PIs to submit; in the past this was a very 
successful endeavor. I'll post on this list if and when that happens 
so that anyone that is interested can get involved, but don't let that 
possibility keep you from submitting any PIs on your own.


Maybe in the meantime, a control system that shuts off the PV, and 
then the batteries, would be worth designing.


Brian Mehalic




On Wed, Feb 1, 2023 at 2:10 PM James Jefferson Jarvis via RE-wrenches 
 wrote:




On 2/1/2023 2:58 PM, Starlight via RE-wrenches wrote:
> Have you (or any) installed surge suppression on the PV input
side to
> clamp the open circuit voltage surge?

That's not where the issue is and isn't really a solution. As I
explained in my previous e-mail, the issue is the open circuit on the
output leaves no where for the energy in the MPPT controllers
inductor
to go and the only option is for the voltage to rise until it finds
somewhere to go.

Surge suppressors, such as sold by Midnite Solar, are nothing more
than
Metal Oxide Varistors. Or in the case of Delta, they are pieces of
wire
in sand. They require large rise in voltage before they conduct.

MOVs are sometimes found on the battery side of inverters and charge
controllers, but their clamp time and voltage before clamping
requires
additional circuitry that works faster to protect fragile
semiconductors.


If you are proposing using a surge supressor to regulate the
voltage of
an island between a charge controller and an inverter when the
battery
is disconnected, that's also a no go. Once the MOV clamps, it stays
clamped until voltage goes essentially to zero or until it blows up.
It's not a regulator.

-

To further 

Re: [RE-wrenches] Remote battery disconnects

[Jason Szumlanski via RE-wrenches]

I have been following this discussion intently. I hate to say it, but it
all sounds like a major case being made for AC-coupled system architecture,
and even integrated "AC Batteries" like Powerwalls and Encharge
that integrate the battery and inverter into listed Energy Storage Systems.
As someone who keeps exploring getting back to DC Coupled systems for some
significant reasons, the complexity and lack of standardization makes that
a big leap.

I started out with Heart 12V inverters and moved toward Xantrex SW and
moved on to Outback GFX and dabbled in other brands before changing
businesses and going basically all grid tie with Enphase, later with some
Powerwalls and then back into battery backup exclusively with Enphase. In
the last three years, I've dabbled with Sol-Ark and done service on a bunch
of DC coupled brands (begrudgingly usually). The Enphase system is so
limited in terms of max battery capacity, but in terms of design simplicity
and safety, I can't think of a better option for consumers right now. The
problem of dealing with high ampacity DC circuits keeps me from wanting to
jump back into DC Coupled systems despite the advantages of cost, capacity
and efficiency for off-grid applications and backup.

So from what I'm reading here, the DC charge control is an issue when DC
batteries are abruptly disconnected. It seems like an AC-coupled PV system
is the answer to that, but it still leaves some DC battery disconnect
issues to be considered, especially the remote disconnect issue that can
come up.

My pipe dream is for Enphase to drastically cut their price and drastically
increase their battery capacity, and then get rid of all of the ridiculous
communication issues that frustrate me endlessly. Their unique AC coupling
that parallels generator output to PV via the System Controller is a novel
approach, albeit limited in flexibility. Absent my dreams coming true,
maybe someone will come along with an integrated answer that solves some of
these DC coupling issues. I'm not holding my breath that standards will be
developed. We're more likely to have a slow march toward AC coupling as
codes make it harder and harder to comply with the DC issues.

Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956


On Wed, Feb 1, 2023 at 4:50 PM Brian Mehalic via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Most firefighters are not electrical engineers; nor are most insurance
> agents. However both of those groups are stakeholders with influence over
> codes and standards. Some may say too much influence, but the fact of the
> matter is that code making is a group/consensus process, and very often
> none of the groups get exactly what they want (in fact sometimes a group
> accepts exactly what it doesn't want to leverage that for something they
> do; yes it often smacks of politics). I would appeal to y'all to submit a
> proposal for the 2026 NEC® - they are due by September of this year. Better
> yet would be to circulate language that this, or some other, group can work
> on, agree on, write a solid technical justification for, and sign their
> names to and submit - the more stakeholders that support a proposal the
> more weight it has.
>
> It seems that the PV Industry Forum, or another similar body, may again
> begin work to develop PV and storage industry stakeholder-consensus PIs to
> submit; in the past this was a very successful endeavor. I'll post on this
> list if and when that happens so that anyone that is interested can get
> involved, but don't let that possibility keep you from submitting any PIs
> on your own.
>
> Maybe in the meantime, a control system that shuts off the PV, and then
> the batteries, would be worth designing.
>
> Brian Mehalic
>
>
>
>
> On Wed, Feb 1, 2023 at 2:10 PM James Jefferson Jarvis via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>>
>>
>> On 2/1/2023 2:58 PM, Starlight via RE-wrenches wrote:
>> > Have you (or any) installed surge suppression on the PV input side to
>> > clamp the open circuit voltage surge?
>>
>> That's not where the issue is and isn't really a solution. As I
>> explained in my previous e-mail, the issue is the open circuit on the
>> output leaves no where for the energy in the MPPT controllers inductor
>> to go and the only option is for the voltage to rise until it finds
>> somewhere to go.
>>
>> Surge suppressors, such as sold by Midnite Solar, are nothing more than
>> Metal Oxide Varistors. Or in the case of Delta, they are pieces of wire
>> in sand. They require large rise in voltage before they conduct.
>>
>> MOVs are sometimes found on the battery side of inverters and charge
>> controllers, but their clamp time and voltage before clamping requires
>> additional circuitry that works faster to protect fragile semiconductors.
>>
>>
>> If you are proposing using a surge supressor to regulate the voltage of

Re: [RE-wrenches] Remote battery disconnects

[Brian Mehalic via RE-wrenches]

Most firefighters are not electrical engineers; nor are most insurance
agents. However both of those groups are stakeholders with influence over
codes and standards. Some may say too much influence, but the fact of the
matter is that code making is a group/consensus process, and very often
none of the groups get exactly what they want (in fact sometimes a group
accepts exactly what it doesn't want to leverage that for something they
do; yes it often smacks of politics). I would appeal to y'all to submit a
proposal for the 2026 NEC® - they are due by September of this year. Better
yet would be to circulate language that this, or some other, group can work
on, agree on, write a solid technical justification for, and sign their
names to and submit - the more stakeholders that support a proposal the
more weight it has.

It seems that the PV Industry Forum, or another similar body, may again
begin work to develop PV and storage industry stakeholder-consensus PIs to
submit; in the past this was a very successful endeavor. I'll post on this
list if and when that happens so that anyone that is interested can get
involved, but don't let that possibility keep you from submitting any PIs
on your own.

Maybe in the meantime, a control system that shuts off the PV, and then the
batteries, would be worth designing.

Brian Mehalic




On Wed, Feb 1, 2023 at 2:10 PM James Jefferson Jarvis via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

>
>
> On 2/1/2023 2:58 PM, Starlight via RE-wrenches wrote:
> > Have you (or any) installed surge suppression on the PV input side to
> > clamp the open circuit voltage surge?
>
> That's not where the issue is and isn't really a solution. As I
> explained in my previous e-mail, the issue is the open circuit on the
> output leaves no where for the energy in the MPPT controllers inductor
> to go and the only option is for the voltage to rise until it finds
> somewhere to go.
>
> Surge suppressors, such as sold by Midnite Solar, are nothing more than
> Metal Oxide Varistors. Or in the case of Delta, they are pieces of wire
> in sand. They require large rise in voltage before they conduct.
>
> MOVs are sometimes found on the battery side of inverters and charge
> controllers, but their clamp time and voltage before clamping requires
> additional circuitry that works faster to protect fragile semiconductors.
>
>
> If you are proposing using a surge supressor to regulate the voltage of
> an island between a charge controller and an inverter when the battery
> is disconnected, that's also a no go. Once the MOV clamps, it stays
> clamped until voltage goes essentially to zero or until it blows up.
> It's not a regulator.
>
> -
>
> To further stir the pot, it is definitely possible to design electronics
> that can deal with load dumps and survive most anything. Aerospace
> electronics come pretty close. But all that costs money and takes space
> to do. Are we comfortable with requiring $16,000 charge controllers so
> they can handle load dumps reliably from a poorly thought out NEC
> requirement? I think the fossil fuel industry would be very happy with
> the cost of renewable energy electronics being an order of magnitude
> more expensive.
>
>
>
>
> >
> > Larry Crutcher
> > Starlight Solar Power Systems
> >
> >
> >
> > On Feb 1, 2023, at 1:23 PM, William Bryce via RE-wrenches
> >  > > wrote:
> >
> > I can also backup what Jim has said, and have seen the same gear
> > destroyed by removing the battery abruptly when the controller is under
> > heavy load. They can die, and sometimes die spectacularly.
> >
> > Have seen SolArk inverters integrated MPPT controllers blow up when
> > lithium battery BMS disconnects. Not a field fixable issue.
> >
> > Just flip off the breaker when the solar is working hard and and the
> > SolArk will give up the smoke.
> >
> > Like I originally said, it’s the non talked about issue that is a big
> > issue depending on what gear your using.
> >
> > On Wed, Feb 1, 2023 at 2:49 PM James Jefferson Jarvis via RE-wrenches
> >  > > wrote:
> >
> >
> >
> > On 2/1/2023 12:25 PM, Alex MeVay via RE-wrenches wrote:
> >  > Although our controllers are probably smaller than what you would
> be
> >  > considering in this discussion, surviving a load dump (suddenly
> >  > disconnected battery) is an engineering requirement for us, and
> > likely
> >  > would be for other responsible MFG's on this list (boB?).  The
> charge
> >  > controller can either handle full input voltage on the output, or
> >  > there is a comparator that will shut the controller down instantly
> >  > when the output voltage gets too high.
> >
> > So that's part of the picture.
> >
> > The other part of the picture is the rest of the system. The
> discussion
> > and what NEC is mandating is that the battery be disconnected. As
> > far as
> > I can tell, there 

Re: [RE-wrenches] Remote battery disconnects

[James Jefferson Jarvis via RE-wrenches]

On 2/1/2023 2:58 PM, Starlight via RE-wrenches wrote:
Have you (or any) installed surge suppression on the PV input side to 
clamp the open circuit voltage surge?


That's not where the issue is and isn't really a solution. As I 
explained in my previous e-mail, the issue is the open circuit on the 
output leaves no where for the energy in the MPPT controllers inductor 
to go and the only option is for the voltage to rise until it finds 
somewhere to go.


Surge suppressors, such as sold by Midnite Solar, are nothing more than 
Metal Oxide Varistors. Or in the case of Delta, they are pieces of wire 
in sand. They require large rise in voltage before they conduct.


MOVs are sometimes found on the battery side of inverters and charge 
controllers, but their clamp time and voltage before clamping requires 
additional circuitry that works faster to protect fragile semiconductors.



If you are proposing using a surge supressor to regulate the voltage of 
an island between a charge controller and an inverter when the battery 
is disconnected, that's also a no go. Once the MOV clamps, it stays 
clamped until voltage goes essentially to zero or until it blows up. 
It's not a regulator.


-

To further stir the pot, it is definitely possible to design electronics 
that can deal with load dumps and survive most anything. Aerospace 
electronics come pretty close. But all that costs money and takes space 
to do. Are we comfortable with requiring $16,000 charge controllers so 
they can handle load dumps reliably from a poorly thought out NEC 
requirement? I think the fossil fuel industry would be very happy with 
the cost of renewable energy electronics being an order of magnitude 
more expensive.







Larry Crutcher
Starlight Solar Power Systems



On Feb 1, 2023, at 1:23 PM, William Bryce via RE-wrenches 
> wrote:


I can also backup what Jim has said, and have seen the same gear 
destroyed by removing the battery abruptly when the controller is under 
heavy load. They can die, and sometimes die spectacularly.


Have seen SolArk inverters integrated MPPT controllers blow up when 
lithium battery BMS disconnects. Not a field fixable issue.


Just flip off the breaker when the solar is working hard and and the 
SolArk will give up the smoke.


Like I originally said, it’s the non talked about issue that is a big 
issue depending on what gear your using.


On Wed, Feb 1, 2023 at 2:49 PM James Jefferson Jarvis via RE-wrenches 
> wrote:




On 2/1/2023 12:25 PM, Alex MeVay via RE-wrenches wrote:
 > Although our controllers are probably smaller than what you would be
 > considering in this discussion, surviving a load dump (suddenly
 > disconnected battery) is an engineering requirement for us, and
likely
 > would be for other responsible MFG's on this list (boB?).  The charge
 > controller can either handle full input voltage on the output, or
 > there is a comparator that will shut the controller down instantly
 > when the output voltage gets too high.

So that's part of the picture.

The other part of the picture is the rest of the system. The discussion
and what NEC is mandating is that the battery be disconnected. As
far as
I can tell, there isn't an explicit requirement in all cases that
all of
the power inputs into the system are all going to go away at exactly
the
same time  or ever. This leaves things like charge controllers
getting input power potentially from PV or wind or grid or generator or
something else. And nothing in the NEC, as far as I can tell, is
mandating that all of the DC loads be disconnected. So the loads are
online. Now the regulation circuit (switching power supply in the case
of a MPPT controller) is regulating variable loads and nothing is
providing substantial resistance to change. Normally the battery is
acting like a very very very big capacitor. But without the battery,
there isn't enough damping in the control loops and voltage stability
will suffer. This is where you get 250 volts on your normally 48 volt
battery bus. Or 3 volts. Or -80 volts. Or all of those in a fraction of
second. This sort of thing is hard on electronics and will cause
failures.


Alex's comment about Genasun's controllers handling full input voltage
on the output is probably unique to their niche product. Looking at
their biggest controller, it appears to support VOC of 34 volts. At 34
volts, he can use 50V or 100V rated components on his output. For a
150V
input controller, you probably can. But you wouldn't because it
would be
too expensive. But on a 600V or 1000V controller, there's just no way
that you do that because 1000V rated components are big and expensive
and their spacing requirements are huge compared 100V level sort of
stuff. So the way bigger 

Re: [RE-wrenches] Remote battery disconnects

[Starlight via RE-wrenches]

Have you (or any) installed surge suppression on the PV input side to clamp the 
open circuit voltage surge? 

Larry Crutcher
Starlight Solar Power Systems



On Feb 1, 2023, at 1:23 PM, William Bryce via RE-wrenches 
 wrote:

I can also backup what Jim has said, and have seen the same gear destroyed by 
removing the battery abruptly when the controller is under heavy load. They can 
die, and sometimes die spectacularly.

Have seen SolArk inverters integrated MPPT controllers blow up when lithium 
battery BMS disconnects. Not a field fixable issue.

Just flip off the breaker when the solar is working hard and and the SolArk 
will give up the smoke. 

Like I originally said, it’s the non talked about issue that is a big issue 
depending on what gear your using.

On Wed, Feb 1, 2023 at 2:49 PM James Jefferson Jarvis via RE-wrenches 
mailto:re-wrenches@lists.re-wrenches.org>> 
wrote:


On 2/1/2023 12:25 PM, Alex MeVay via RE-wrenches wrote:
> Although our controllers are probably smaller than what you would be
> considering in this discussion, surviving a load dump (suddenly
> disconnected battery) is an engineering requirement for us, and likely
> would be for other responsible MFG's on this list (boB?).  The charge
> controller can either handle full input voltage on the output, or
> there is a comparator that will shut the controller down instantly
> when the output voltage gets too high.

So that's part of the picture.

The other part of the picture is the rest of the system. The discussion 
and what NEC is mandating is that the battery be disconnected. As far as 
I can tell, there isn't an explicit requirement in all cases that all of 
the power inputs into the system are all going to go away at exactly the 
same time  or ever. This leaves things like charge controllers 
getting input power potentially from PV or wind or grid or generator or 
something else. And nothing in the NEC, as far as I can tell, is 
mandating that all of the DC loads be disconnected. So the loads are 
online. Now the regulation circuit (switching power supply in the case 
of a MPPT controller) is regulating variable loads and nothing is 
providing substantial resistance to change. Normally the battery is 
acting like a very very very big capacitor. But without the battery, 
there isn't enough damping in the control loops and voltage stability 
will suffer. This is where you get 250 volts on your normally 48 volt 
battery bus. Or 3 volts. Or -80 volts. Or all of those in a fraction of 
second. This sort of thing is hard on electronics and will cause failures.


Alex's comment about Genasun's controllers handling full input voltage 
on the output is probably unique to their niche product. Looking at 
their biggest controller, it appears to support VOC of 34 volts. At 34 
volts, he can use 50V or 100V rated components on his output. For a 150V 
input controller, you probably can. But you wouldn't because it would be 
too expensive. But on a 600V or 1000V controller, there's just no way 
that you do that because 1000V rated components are big and expensive 
and their spacing requirements are huge compared 100V level sort of 
stuff. So the way bigger MPPT controllers deal with load dump is with 
transient voltage supression or other diodes to handle the voltage spike 
caused by the inductor when the load goes away. When operated in 
parameters, these parts don't wear out. But it can be interesting to 
size them adequately to account for inductance elsewhere in the system 
adding to voltage and energy that has to be absorbed.


There is a very simple experiment that anybody can perform to see how 
equipment handles a load dump: Simply wait for a sunny day and turn off 
the battery breaker. If no magic smoke was released, turn back on 
battery breaker. If still no magic smoke was released, then great, your 
system survived a load dump.

If you are at all uncomfortable doing this and/or your system gets 
destroyed in the process, think back to my earlier security comments 
about having a self destruct switch on the outside of your building 
allowing anyone walking by to do this experiment for you.

I have personally destroyed Outback, Midnite, and Morningstar 
controllers inadvertently or intentionally doing load dumps by shutting 
off their output breaker. Typically the TVS diodes short out and 
secondary over current protection (circuit breaker) trips before things 
catch on fire. Usuaully the UL94V0 rating on the circuit board and the 
box the circuit board is in prevents fire from spreading when things do 
get wild.

But I've also seen all of those brands survive a load dump.

I have multiple customer who have fielded lithium battery systems to 
cold locations and have had battery BMS disconnect the battery from the 
rest of the system. Ten's of thousands of dollars of equipment has been 
destroyed in these islanding events.


Some thoughts, for what they are worth.

-James Jarvis
APRS World, LLC

Re: [RE-wrenches] Remote battery disconnects

[William Bryce via RE-wrenches]

I can also backup what Jim has said, and have seen the same gear destroyed
by removing the battery abruptly when the controller is under heavy load.
They can die, and sometimes die spectacularly.

Have seen SolArk inverters integrated MPPT controllers blow up when lithium
battery BMS disconnects. Not a field fixable issue.

Just flip off the breaker when the solar is working hard and and the SolArk
will give up the smoke.

Like I originally said, it’s the non talked about issue that is a big issue
depending on what gear your using.

On Wed, Feb 1, 2023 at 2:49 PM James Jefferson Jarvis via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

>
>
> On 2/1/2023 12:25 PM, Alex MeVay via RE-wrenches wrote:
> > Although our controllers are probably smaller than what you would be
> > considering in this discussion, surviving a load dump (suddenly
> > disconnected battery) is an engineering requirement for us, and likely
> > would be for other responsible MFG's on this list (boB?).  The charge
> > controller can either handle full input voltage on the output, or
> > there is a comparator that will shut the controller down instantly
> > when the output voltage gets too high.
>
> So that's part of the picture.
>
> The other part of the picture is the rest of the system. The discussion
> and what NEC is mandating is that the battery be disconnected. As far as
> I can tell, there isn't an explicit requirement in all cases that all of
> the power inputs into the system are all going to go away at exactly the
> same time  or ever. This leaves things like charge controllers
> getting input power potentially from PV or wind or grid or generator or
> something else. And nothing in the NEC, as far as I can tell, is
> mandating that all of the DC loads be disconnected. So the loads are
> online. Now the regulation circuit (switching power supply in the case
> of a MPPT controller) is regulating variable loads and nothing is
> providing substantial resistance to change. Normally the battery is
> acting like a very very very big capacitor. But without the battery,
> there isn't enough damping in the control loops and voltage stability
> will suffer. This is where you get 250 volts on your normally 48 volt
> battery bus. Or 3 volts. Or -80 volts. Or all of those in a fraction of
> second. This sort of thing is hard on electronics and will cause failures.
>
>
> Alex's comment about Genasun's controllers handling full input voltage
> on the output is probably unique to their niche product. Looking at
> their biggest controller, it appears to support VOC of 34 volts. At 34
> volts, he can use 50V or 100V rated components on his output. For a 150V
> input controller, you probably can. But you wouldn't because it would be
> too expensive. But on a 600V or 1000V controller, there's just no way
> that you do that because 1000V rated components are big and expensive
> and their spacing requirements are huge compared 100V level sort of
> stuff. So the way bigger MPPT controllers deal with load dump is with
> transient voltage supression or other diodes to handle the voltage spike
> caused by the inductor when the load goes away. When operated in
> parameters, these parts don't wear out. But it can be interesting to
> size them adequately to account for inductance elsewhere in the system
> adding to voltage and energy that has to be absorbed.
>
>
> There is a very simple experiment that anybody can perform to see how
> equipment handles a load dump: Simply wait for a sunny day and turn off
> the battery breaker. If no magic smoke was released, turn back on
> battery breaker. If still no magic smoke was released, then great, your
> system survived a load dump.
>
> If you are at all uncomfortable doing this and/or your system gets
> destroyed in the process, think back to my earlier security comments
> about having a self destruct switch on the outside of your building
> allowing anyone walking by to do this experiment for you.
>
> I have personally destroyed Outback, Midnite, and Morningstar
> controllers inadvertently or intentionally doing load dumps by shutting
> off their output breaker. Typically the TVS diodes short out and
> secondary over current protection (circuit breaker) trips before things
> catch on fire. Usuaully the UL94V0 rating on the circuit board and the
> box the circuit board is in prevents fire from spreading when things do
> get wild.
>
> But I've also seen all of those brands survive a load dump.
>
> I have multiple customer who have fielded lithium battery systems to
> cold locations and have had battery BMS disconnect the battery from the
> rest of the system. Ten's of thousands of dollars of equipment has been
> destroyed in these islanding events.
>
>
> Some thoughts, for what they are worth.
>
> -James Jarvis
> APRS World, LLC
>
>
> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: 

Re: [RE-wrenches] Remote battery disconnects

[James Jefferson Jarvis via RE-wrenches]

On 2/1/2023 12:25 PM, Alex MeVay via RE-wrenches wrote:

Although our controllers are probably smaller than what you would be
considering in this discussion, surviving a load dump (suddenly
disconnected battery) is an engineering requirement for us, and likely
would be for other responsible MFG's on this list (boB?).  The charge
controller can either handle full input voltage on the output, or
there is a comparator that will shut the controller down instantly
when the output voltage gets too high.


So that's part of the picture.

The other part of the picture is the rest of the system. The discussion 
and what NEC is mandating is that the battery be disconnected. As far as 
I can tell, there isn't an explicit requirement in all cases that all of 
the power inputs into the system are all going to go away at exactly the 
same time  or ever. This leaves things like charge controllers 
getting input power potentially from PV or wind or grid or generator or 
something else. And nothing in the NEC, as far as I can tell, is 
mandating that all of the DC loads be disconnected. So the loads are 
online. Now the regulation circuit (switching power supply in the case 
of a MPPT controller) is regulating variable loads and nothing is 
providing substantial resistance to change. Normally the battery is 
acting like a very very very big capacitor. But without the battery, 
there isn't enough damping in the control loops and voltage stability 
will suffer. This is where you get 250 volts on your normally 48 volt 
battery bus. Or 3 volts. Or -80 volts. Or all of those in a fraction of 
second. This sort of thing is hard on electronics and will cause failures.



Alex's comment about Genasun's controllers handling full input voltage 
on the output is probably unique to their niche product. Looking at 
their biggest controller, it appears to support VOC of 34 volts. At 34 
volts, he can use 50V or 100V rated components on his output. For a 150V 
input controller, you probably can. But you wouldn't because it would be 
too expensive. But on a 600V or 1000V controller, there's just no way 
that you do that because 1000V rated components are big and expensive 
and their spacing requirements are huge compared 100V level sort of 
stuff. So the way bigger MPPT controllers deal with load dump is with 
transient voltage supression or other diodes to handle the voltage spike 
caused by the inductor when the load goes away. When operated in 
parameters, these parts don't wear out. But it can be interesting to 
size them adequately to account for inductance elsewhere in the system 
adding to voltage and energy that has to be absorbed.



There is a very simple experiment that anybody can perform to see how 
equipment handles a load dump: Simply wait for a sunny day and turn off 
the battery breaker. If no magic smoke was released, turn back on 
battery breaker. If still no magic smoke was released, then great, your 
system survived a load dump.


If you are at all uncomfortable doing this and/or your system gets 
destroyed in the process, think back to my earlier security comments 
about having a self destruct switch on the outside of your building 
allowing anyone walking by to do this experiment for you.


I have personally destroyed Outback, Midnite, and Morningstar 
controllers inadvertently or intentionally doing load dumps by shutting 
off their output breaker. Typically the TVS diodes short out and 
secondary over current protection (circuit breaker) trips before things 
catch on fire. Usuaully the UL94V0 rating on the circuit board and the 
box the circuit board is in prevents fire from spreading when things do 
get wild.


But I've also seen all of those brands survive a load dump.

I have multiple customer who have fielded lithium battery systems to 
cold locations and have had battery BMS disconnect the battery from the 
rest of the system. Ten's of thousands of dollars of equipment has been 
destroyed in these islanding events.



Some thoughts, for what they are worth.

-James Jarvis
APRS World, LLC


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Re: [RE-wrenches] Remote battery disconnects

[Jeff Clearwater via RE-wrenches]

 fire starts (or an earthquake happens 
or a dump truck runs into your house, etc.).


When California first adopted roof clearances for fire fighters, I 
got my feelings hurt because I was losing business and I did not 
understand what it takes to fight a house fire.  I spoke with a few 
fire fighters and learned about roof and wall venting and how it is 
affected by prevailing winds.  I came around to appreciate there is 
a real need for rooftop fire setbacks.


It is self-evident why firefighters would not want to cut into a 
wall with a demo saw if there are energized, high amperage 
conductors in or on that wall.  This code requirement for battery 
disconnecting means is fundamentally sensible.  That ends the 
discussion for me.


Oh, yeah, the charge controller blowing up thing:  Does anyone have 
any factual data to share on this?  Regardless of that, does it 
really matter if the charge controller is saved but the house burns 
down?


The islanding thing:  To be compliant, all ungrounded battery 
conductors need to be disconnected.  This includes the charge 
controller circuit(s).  With the charge controllers and inverters 
disconnected from the batteries and from each other there cannot be 
DC “islanding”.


The house flooding thing:  At the surface, it appears you have a 
choice of disasters:  flood or fire.  I submit that fire is more 
destructive (I don’t think many people have died from a ruptured 
water pipe).  I don’t think it has to be either or:  Find a way to 
provide emergency power to freeze protection devices with that 
disconnect waived or under key in cooperation with the fire 
department.  This may mean the batteries need to remain connected.  
Put those leads in metal raceway and mark their locations from the 
outside. Work with building and fire officials.  Limit your liability.


Thanks again to all of you for the discussion.  I know what I need 
to do.


William Miller

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*James Jarvis [mailto:j...@aprsworld.com]
*Sent:* Saturday, January 28, 2023 7:03 PM
*To:* Brian Mehalic
*Cc:* RE-wrenches; will...@millersolar.com
*Subject:* Re: [RE-wrenches] Remote battery disconnects

Brian and William,

With all due respect, I think your geographical location of 
California may be limiting in your understanding of the implications 
of local power security.


Where I am in Minnesota and where I work in Alaska, loss of power 
and backup power can have very expensive consequences. When it is 
-30F outside and howling wind, buildings only have a matter of hours 
before their interiors will drop below freezing. A few hours after 
that pipes start to freeze and break. Pressurized water then starts 
to spray everywhere and then things can very quickly run into 
six-figure dollars amounts of damage. So one way of reducing this 
risk is by installing an ESS.


Around here, prior to the latest NEC, we didn't have exterior 
disconnects available for anyone to shut off power. We still don't 
for businesses.


My point is that NEC is mandating that there be zero security of a 
buildings electrical systems by requiring publicly accessible 
disconnects on backup systems. And if NEC wasn't so prescriptive, 
there could be slightly more secure alternatives such as a KNOXBOX 
or access controlled disconnects.


William: I also disagree with your premise that you'll test the 
battery disconnect system after dark. That's not a test; that's just 
cheating. You had a knowledge person tell you that the MPPT 
controllers can and do blow up when they lose their voltage 
reference (battery) under load. And removing the battery from the 
circuit does allow the charge controllers to island with the 
inverter and DC loads and do other damage. I know of a telecom 
customer that had hundreds of thousands of dollars of damage when 
their battery became disconnected. If you are unwilling to test it 
at full load, I'd guess you know that the whole concept is a dumb idea.



-James Jefferson Jarvis
APRS World, LLC
+1-507-454-2727

http://www.aprsworld.com/

On Sat, Jan 28, 2023 at 7:35 PM Brian Mehalic 
 wrote:


Every single house I’ve looked at in my town has a breaker panel
with a main service disconnect on the outside of the house
already. So in many cases we are well beyond worrying about
someone “flicking your switch!”

In fact, in addition to the emergency disconnect requirement for
stationary standby batteries [480.7(B)] and ESS [706.15(B)] in
one- and two-family dwellings, also added in 2020 was the
requirement for an emergency disconnect for services on those
same one- and two-family dwellings [230.85].

Brian Mehalic



On Jan 28, 2023, at 5:58 PM, James Jarvis via RE-wrenches
 wrote:



It would be nice if the decision was up to the owner /
occupant of the property. I, for one, do not want any rand

Re: [RE-wrenches] Remote battery disconnects

[Alex MeVay via RE-wrenches]

> Oh, yeah, the charge controller blowing up thing:  Does anyone have any 
> factual data to share on this?

Although our controllers are probably smaller than what you would be
considering in this discussion, surviving a load dump (suddenly
disconnected battery) is an engineering requirement for us, and likely
would be for other responsible MFG's on this list (boB?).  The charge
controller can either handle full input voltage on the output, or
there is a comparator that will shut the controller down instantly
when the output voltage gets too high.

The only time we run into trouble during a load dump is if there is
another charger that is less well-behaved, such as an alternator,
running at the same time.  This most commonly happens on sailboats,
when someone turns off the ignominious battery switch with the engine
still running.  The alternator spikes the battery line from 12V up to
50-100V+ before the alternator regulator can respond, and the charge
controller (and other electronics aboard) might not survive.

Tangential to this conversation, it seems battery switches cause our
marine and RV customers way more problems than they solve.  It seems
important to have one, but I wish they were a little more towards the
break-glass-in-case-of-emergency end of the accessibility spectrum.

Thank as always, Wrenches, for the information you share and high
level of discourse.

Alex MeVay

Genasun * Blue Sky Energy * http://sunforgellc.com
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Re: [RE-wrenches] Remote battery disconnects

[Jerry Shafer via RE-wrenches]

house burns down?
>
>
>
> The islanding thing:  To be compliant, all ungrounded battery conductors
> need to be disconnected.  This includes the charge controller circuit(s).
> With the charge controllers and inverters disconnected from the batteries
> and from each other there cannot be DC “islanding”.
>
>
>
> The house flooding thing:  At the surface, it appears you have a choice of
> disasters:  flood or fire.  I submit that fire is more destructive (I don’t
> think many people have died from a ruptured water pipe).  I don’t think it
> has to be either or:  Find a way to provide emergency power to freeze
> protection devices with that disconnect waived or under key in cooperation
> with the fire department.  This may mean the batteries need to remain
> connected.  Put those leads in metal raceway and mark their locations from
> the outside.  Work with building and fire officials.  Limit your liability.
>
>
>
> Thanks again to all of you for the discussion.  I know what I need to do.
>
>
>
> William Miller
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* James Jarvis [mailto:j...@aprsworld.com]
> *Sent:* Saturday, January 28, 2023 7:03 PM
> *To:* Brian Mehalic
> *Cc:* RE-wrenches; will...@millersolar.com
> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>
>
>
> Brian and William,
>
>
>
> With all due respect, I think your geographical location of California may
> be limiting in your understanding of the implications of local power
> security.
>
>
>
> Where I am in Minnesota and where I work in Alaska, loss of power and
> backup power can have very expensive consequences. When it is -30F outside
> and howling wind, buildings only have a matter of hours before their
> interiors will drop below freezing. A few hours after that pipes start to
> freeze and break. Pressurized water then starts to spray everywhere and
> then things can very quickly run into six-figure dollars amounts of damage.
> So one way of reducing this risk is by installing an ESS.
>
>
>
> Around here, prior to the latest NEC, we didn't have exterior disconnects
> available for anyone to shut off power. We still don't for businesses.
>
>
>
> My point is that NEC is mandating that there be zero security of a
> buildings electrical systems by requiring publicly accessible disconnects
> on backup systems. And if NEC wasn't so prescriptive, there could be
> slightly more secure alternatives such as a KNOXBOX or access controlled
> disconnects.
>
>
>
> William: I also disagree with your premise that you'll test the battery
> disconnect system after dark. That's not a test; that's just cheating. You
> had a knowledge person tell you that the MPPT controllers can and do blow
> up when they lose their voltage reference (battery) under load. And
> removing the battery from the circuit does allow the charge controllers to
> island with the inverter and DC loads and do other damage. I know of a
> telecom customer that had hundreds of thousands of dollars of damage when
> their battery became disconnected. If you are unwilling to test it at full
> load, I'd guess you know that the whole concept is a dumb idea.
>
>
> -James Jefferson Jarvis
> APRS World, LLC
> +1-507-454-2727
>
> http://www.aprsworld.com/
>
>
>
>
>
> On Sat, Jan 28, 2023 at 7:35 PM Brian Mehalic 
> wrote:
>
> Every single house I’ve looked at in my town has a breaker panel with a
> main service disconnect on the outside of the house already. So in many
> cases we are well beyond worrying about someone “flicking your switch!”
>
>
>
> In fact, in addition to the emergency disconnect requirement for
> stationary standby batteries [480.7(B)] and ESS [706.15(B)] in one- and
> two-family dwellings, also added in 2020 was the requirement for an
> emergency disconnect for services on those same one- and two-family
> dwellings [230.85].
>
> Brian Mehalic
>
>
>
> On Jan 28, 2023, at 5:58 PM, James Jarvis via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
> 
>
> It would be nice if the decision was up to the owner / occupant of the
> property. I, for one, do not want any random person to be able to turn off
> my house or business with the flick of a switch. I feel strongly that there
> is far too much fear mongering in NEC with relation to renewable energy.
>
>
> -James Jefferson Jarvis
> APRS World, LLC
> +1-507-454-2727
>
> http://www.aprsworld.com/
>
>
>
>
>
> On Sat, Jan 28, 2023 at 6:22 PM William Miller via RE-wrenches <
> re-wrenches@lists.r

Re: [RE-wrenches] Remote battery disconnects

[Brian Mehalic via RE-wrenches]

 thing:  To be compliant, all ungrounded battery
conductors need to be disconnected.  This includes the
charge controller circuit(s).  With the charge controllers
and inverters disconnected from the batteries and from each
other there cannot be DC “islanding”.
 
The
house flooding thing:  At the surface, it appears you have a
choice of disasters:  flood or fire.  I submit that fire is
more destructive (I don’t think many people have died from a
ruptured water pipe).  I don’t think it has to be either
or:  Find a way to provide emergency power to freeze
protection devices with that disconnect waived or under key
in cooperation with the fire department.  This may mean the
batteries need to remain connected.  Put those leads in
metal raceway and mark their locations from the outside. 
Work with building and fire officials.  Limit your
liability.
 
Thanks
again to all of you for the discussion.  I know what I need
to do.
 
William
Miller
 
Miller
Solar
17395
Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com
CA
Lic. 773985
 
 
From:
James Jarvis [mailto:j...@aprsworld.com]

Sent: Saturday, January 28, 2023 7:03 PM
To: Brian Mehalic
Cc: RE-wrenches; will...@millersolar.com
Subject: Re: [RE-wrenches] Remote battery disconnects
 

  Brian and William,
  
 
  
  
With all due respect, I think your
  geographical location of California may be limiting in
  your understanding of the implications of local power
  security. 
  
  
 
  
  
Where I am in Minnesota and where I
  work in Alaska, loss of power and backup power can have
  very expensive consequences. When it is -30F outside and
  howling wind, buildings only have a matter of hours before
  their interiors will drop below freezing. A few hours
  after that pipes start to freeze and break. Pressurized
  water then starts to spray everywhere and then things can
  very quickly run into six-figure dollars amounts of
  damage. So one way of reducing this risk is by installing
  an ESS.
  
  
 
  
  
Around here, prior to the latest NEC,
  we didn't have exterior disconnects available for anyone
  to shut off power. We still don't for businesses. 
  
  
 
  
  
My point is that NEC is mandating that
  there be zero security of a buildings electrical systems
  by requiring publicly accessible disconnects on backup
  systems. And if NEC wasn't so prescriptive, there could be
  slightly more secure alternatives such as a KNOXBOX or
  access controlled disconnects. 
  
  
 
  
  
William: I also disagree with your
  premise that you'll test the battery disconnect system
  after dark. That's not a test; that's just cheating. You
  had a knowledge person tell you that the MPPT controllers
  can and do blow up when they lose their voltage reference
  (battery) under load. And removing the battery from the
  circuit does allow the charge controllers to island with
  the inverter and DC loads and do other damage. I know of a
  telecom customer that had hundreds of thousands of dollars
  of damage when their battery became disconnected. If you
  are unwilling to test it at full load, I'd guess you know
  that the whole concept is a dumb idea.
  
  



  

  
-James Jefferson Jarvis
  APRS World, LLC
  +1-507-454-2727
  
  http://www.aprsworld.com/

  

 
  

 

  
On Sat, Jan 28, 2023 at 7:35 PM Brian
  Mehalic <br...@solarenergy.org>
  wrote:
  
  

  Every single house I’ve looked at in
my town has a breaker panel with a main service
disconnect on the outside of the house alrea

Re: [RE-wrenches] Remote battery disconnects

[William Miller via RE-wrenches]

James, Brian and others:



Thank you all for the lively discussion.  I am always interested in my
colleague’s perspectives and this has been illuminating.



It appears to me the discussion has forked:  One topic is how to deal with
the reality of the new code regarding a very narrow scenario: ESS inside of
a residence.  The other topic is: has the NEC evolved to be overly
restrictive without factual basis?



Regarding the first topic, it’s in black and white that we must provide
battery disconnecting means for energy storage systems located in one or
two family homes if the battery voltage exceeds 60 VDC.  There are very few
areas that do not adopt the NEC.  If you install ESS you will eventually
have to deal with this code requirement one way or another.



Due to lax enforcement or unfamiliarity on the part of local building
departments, some of you may be able to skirt this requirement.  This is
great until something happens.  If your non-compliant installation causes a
loss, you will end up in the defendants chair, not the building inspector.



Here is how I approach these compliance conundrums:  If I could argue the
code does not apply or there is a good reason to waive the requirement; if
the building official agrees; if I feel the installation is really and
truly safe without meeting the  requirement—only then could I proceed
without the disconnect.  Otherwise I am going to have to find a way to
comply.



As contractors, each of you makes those decisions every day:  What is safe
enough for my clients?  If any of you think you know more than the people
who write the codes, then install what you can get away with and keep your
fingers crossed.  I am not willing to live like that.



Regarding the second topic: Are we being picked on by an overly
scare-mongering NFPA?



What is interesting here is that while most electrical codes are trying to
prevent house fires, this particular section is trying to protect fire
fighters after a fire starts (or an earthquake happens or a dump truck runs
into your house, etc.).



When California first adopted roof clearances for fire fighters, I got my
feelings hurt because I was losing business and I did not understand what
it takes to fight a house fire.  I spoke with a few fire fighters and
learned about roof and wall venting and how it is affected by prevailing
winds.  I came around to appreciate there is a real need for rooftop fire
setbacks.



It is self-evident why firefighters would not want to cut into a wall with
a demo saw if there are energized, high amperage conductors in or on that
wall.  This code requirement for battery disconnecting means is
fundamentally sensible.  That ends the discussion for me.



Oh, yeah, the charge controller blowing up thing:  Does anyone have any
factual data to share on this?  Regardless of that, does it really matter
if the charge controller is saved but the house burns down?



The islanding thing:  To be compliant, all ungrounded battery conductors
need to be disconnected.  This includes the charge controller circuit(s).
With the charge controllers and inverters disconnected from the batteries
and from each other there cannot be DC “islanding”.



The house flooding thing:  At the surface, it appears you have a choice of
disasters:  flood or fire.  I submit that fire is more destructive (I don’t
think many people have died from a ruptured water pipe).  I don’t think it
has to be either or:  Find a way to provide emergency power to freeze
protection devices with that disconnect waived or under key in cooperation
with the fire department.  This may mean the batteries need to remain
connected.  Put those leads in metal raceway and mark their locations from
the outside.  Work with building and fire officials.  Limit your liability.



Thanks again to all of you for the discussion.  I know what I need to do.



William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* James Jarvis [mailto:j...@aprsworld.com]
*Sent:* Saturday, January 28, 2023 7:03 PM
*To:* Brian Mehalic
*Cc:* RE-wrenches; will...@millersolar.com
*Subject:* Re: [RE-wrenches] Remote battery disconnects



Brian and William,



With all due respect, I think your geographical location of California may
be limiting in your understanding of the implications of local power
security.



Where I am in Minnesota and where I work in Alaska, loss of power and
backup power can have very expensive consequences. When it is -30F outside
and howling wind, buildings only have a matter of hours before their
interiors will drop below freezing. A few hours after that pipes start to
freeze and break. Pressurized water then starts to spray everywhere and
then things can very quickly run into six-figure dollars amounts of damage.
So one way of reducing this risk is by installing an ESS.



Around here, prior to the latest NEC, we didn't have exterior disconnects
available for anyone to shut off power

Re: [RE-wrenches] Remote battery disconnects

[Christopher Warfel via RE-wrenches]

CA Lic. 773985

*From:*RE-wrenches
[mailto:re-wrenches-boun...@lists.re-wrenches.org]
*On Behalf Of *Jeremy Rodriguez via RE-wrenches
*Sent:* Saturday, January 28, 2023 10:12 AM
*To:* cwar...@entech-engineering.com; RE-wrenches
*Cc:* Jeremy Rodriguez
*Subject:* Re: [RE-wrenches] Remote battery disconnects



*2020 Code Language:*

/*480.7 DC Disconnect Methods.*/

/*(A) Disconnecting Means.*/*//*/A disconnecting
means shall be provided for all ungrounded
conductors derived from a stationary battery system
with a voltage over 60 volts dc. A disconnecting
means shall be readily accessible and located within
sight of the battery system./

/*N*/*//*/*(B) Emergency Disconnect.*/*//*/For
one-family and two-family dwellings, a disconnecting
means or its remote control for a stationary battery
system shall be located at a readily accessible
location outside the building for emergency use. The
disconnect shall be labeled “EMERGENCY DISCONNECT”./

*/N/*/*(C) Disconnection of Series Battery
Circuits.*/*//*/Battery circuits exceeding 240 volts
dc nominal between conductors or to ground and
subject to field servicing shall have provisions to
disconnect the series-connected strings into
segments not exceeding 240 volts dc nominal for
maintenance by qualified persons. Non-load-break
bolted or plug-in disconnects shall be permitted./

Jeremy Rodriguez

Solar Installation / Design

All Solar, Inc.

1453 M St.

Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.



On Jan 28, 2023, at 7:28 AM, Christopher Warfel via
RE-wrenches  wrote:



Seems confusing that the AHJ is requiring a
disconnect for AC wiring, not specific to which
or both panel types, and then a dc disconnect
with no code reference.  Was trying to convey a
reasonable, safe approach.  A lot of bad
information from fire department solar
consultants making a lot of money fear
mongering, which has led to this type of
situation.  Chris

On 1/27/2023 3:35 PM, William Miller via
RE-wrenches wrote:

Glenn:

As I wrote, a DC disconnect is required.
Here is an excerpt from the Q with the
building official:

4.Will you be requiring an external
disconnect to disconnect the AC output of
the inverter system from premise wiring?

Yes, as required per 230.85

5.Will you be requiring an external
disconnect to disconnect batteries from the
inverters?

Yes

If the DC disconnect was not required I
would not be wasting everyone’s time with my
post.  I try to be careful about that,
researching on my own before posting and
trying to make my questions very clear.  I
also try not to embarrass myself with dumb
questions, but that does happen occasionally…

William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com
<http://www.millersolar.com/>

CA Lic. 773985

*From:*RE-wrenches
[mailto:re-wrenches-boun...@lists.re-wrenches.org]
*On Behalf Of *Glenn Burt via RE-wrenches
*Sent:* Friday, January 27, 2023 11:46 AM
*To:* William Miller via RE-wrenches
*Cc:* Glenn Burt
*Subject:* Re: [RE-wrenches] Remote battery
    disconnects

Does the AHJ really want the batteries
disconnected from conductors, or does he
really just want the inverters to stop
operating and producing AC with

Re: [RE-wrenches] Remote battery disconnects

[Bradley Bassett via RE-wrenches]

My design for one customer was to have one initiator for the PV and
inverter, and a separate one for the battery initiator. And, to put up a
plaque giving instructions to turn off the PV and inverter first, then the
battery.

Brad

On Sat, Jan 28, 2023 at 4:22 PM William Miller via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Esteemed wrenches:
>
> Well if my house is on fire and the entry of fire responders is delayed
> for lack of a disconnect, I choose having the disconnect. I can worry about
> the charge controllers later.
>
> Others may prioritize their charge controller over their homes…
>
> Put a cable-tie lock in the closed position to discourage kids from
> messing with it. Test it only after dark.
>
> William
>
> On Sat, Jan 28, 2023 at 2:32 PM William Bryce <
> wlbr...@pineridgeproducts.com> wrote:
>
>> All
>>
>> One thing that no one is talking about is what happens to the MPPT charge
>> controllers when the Battery Disconnect trips when the charge controllers
>> are under full load.
>> Many will blow up. Try turning off the battery breaker on a SolaArk  when
>> the charge controllers are maxed, and see if you get lucky.
>>
>> On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches <
>> re-wrenches@lists.re-wrenches.org> wrote:
>>
>>> Jeremy:
>>>
>>>
>>>
>>> Thanks for posting the code references for those that had never looked
>>> them up.
>>>
>>>
>>>
>>> Chris:
>>>
>>>
>>>
>>> What do you mean by “a disconnect for AC wiring, not specific to which
>>> or both panel types”?
>>>
>>>
>>>
>>> All:
>>>
>>>
>>>
>>> Code references are handy when receiving edicts from building officials,
>>> but not required, IMHO, for two reasons:  The contractor should already be
>>> versed in the codes and, building departments can mandate their own
>>> requirements above and beyond the code.
>>>
>>>
>>>
>>> It may seem redundant to require an AC disconnect for premise wiring as
>>> well as a DC battery disconnect.  In most cases if you disconnect the
>>> inverter from the batteries the AC power goes off.  However if the
>>> generator is running at the time, some battery inverters can operate when
>>> disconnected from batteries.  So to completely de-energize all components
>>> of an off-grid home you need to disconnect the generator and the battery
>>> leads.
>>>
>>>
>>>
>>> In this case the home is required to have fire sprinklers.  There is
>>> pressure pump to provide flow to these fire sprinklers-- said pump being
>>> powered by the inverter/battery system.  I am going to apply for a waiver
>>> to remove the DC disconnect requirement on the grounds that the pressure
>>> pump is essential fire suppression equipment.  Instead I will propose to
>>> supply an AC disconnect (meeting all requirements for accessibility and
>>> marking) that will disconnect all premise wiring except the pressure pump.
>>>
>>>
>>>
>>> By the way, I will of course be trying to apply the logic that the
>>> voltage specification is for nominal battery voltage and this project
>>> having a nominal 48 volt bank does not require the battery disconnect.
>>>
>>>
>>>
>>> I will let the group know what response I receive.  Regardless of how
>>> this works in this jurisdiction, I think these are both valid arguments
>>> worth trying in any jurisdiction requiring the battery disconnect.  Some
>>> officials are amenable to dialog and negotiation and some are less so.
>>>
>>>
>>>
>>>
>>>
>>> William Miller
>>>
>>>
>>>
>>> Miller Solar
>>>
>>> 17395 Oak Road, Atascadero, CA 93422
>>>
>>> 805-438-5600
>>>
>>> www.millersolar.com
>>>
>>> CA Lic. 773985
>>>
>>>
>>>
>>>
>>>
>>> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
>>> Behalf Of *Jeremy Rodriguez via RE-wrenches
>>> *Sent:* Saturday, January 28, 2023 10:12 AM
>>> *To:* cwar...@entech-engineering.com; RE-wrenches
>>> *Cc:* Jeremy Rodriguez
>>> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>>>
>>>
>>>
>>> 
>>>
>>> *2020 Code Language:*
>>>
>>> *480.7 DC Discon

Re: [RE-wrenches] Remote battery disconnects

[Brian Mehalic via RE-wrenches]

nerator is running at the time, some battery inverters can operate when disconnected from batteries.  So to completely de-energize all components of an off-grid home you need to disconnect the generator and the battery leads. In this case the home is required to have fire sprinklers.  There is pressure pump to provide flow to these fire sprinklers-- said pump being powered by the inverter/battery system.  I am going to apply for a waiver to remove the DC disconnect requirement on the grounds that the pressure pump is essential fire suppression equipment.  Instead I will propose to supply an AC disconnect (meeting all requirements for accessibility and marking) that will disconnect all premise wiring except the pressure pump.   By the way, I will of course be trying to apply the logic that the voltage specification is for nominal battery voltage and this project having a nominal 48 volt bank does not require the battery disconnect. I will let the group know what response I receive.  Regardless of how this works in this jurisdiction, I think these are both valid arguments worth trying in any jurisdiction requiring the battery disconnect.  Some officials are amenable to dialog and negotiation and some are less so.  William Miller Miller Solar17395 Oak Road, Atascadero, CA 93422805-438-5600www.millersolar.comCA Lic. 773985  From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jeremy Rodriguez via RE-wrenchesSent: Saturday, January 28, 2023 10:12 AMTo: cwar...@entech-engineering.com; RE-wrenchesCc: Jeremy RodriguezSubject: Re: [RE-wrenches] Remote battery disconnects 2020 Code Language:480.7 DC Disconnect Methods.(A) Disconnecting Means. A disconnecting means shall be provided for all ungrounded conductors derived from a stationary battery system with a voltage over 60 volts dc. A disconnecting means shall be readily accessible and located within sight of the battery system.N (B) Emergency Disconnect. For one-family and two-family dwellings, a disconnecting means or its remote control for a stationary battery system shall be located at a readily accessible location outside the building for emergency use. The disconnect shall be labeled “EMERGENCY DISCONNECT”.N (C) Disconnection of Series Battery Circuits. Battery circuits exceeding 240 volts dc nominal between conductors or to ground and subject to field servicing shall have provisions to disconnect the series-connected strings into segments not exceeding 240 volts dc nominal for maintenance by qualified persons. Non-load-break bolted or plug-in disconnects shall be permitted. Jeremy Rodriguez  Solar Installation / DesignAll Solar, Inc. 1453 M St. Penrose Colorado 81240 Sent by Jeremy's iPhone. Sorry for typos and shorthand. On Jan 28, 2023, at 7:28 AM, Christopher Warfel via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote: Seems confusing that the AHJ is requiring a disconnect for AC wiring, not specific to which or both panel types, and then a dc disconnect with no code reference.  Was trying to convey a reasonable, safe approach.  A lot of bad information from fire department solar consultants making a lot of money fear mongering, which has led to this type of situation.  ChrisOn 1/27/2023 3:35 PM, William Miller via RE-wrenches wrote:Glenn: As I wrote, a DC disconnect is required.  Here is an excerpt from the Q with the building official: 4.   Will you be requiring an external disconnect to disconnect the AC output of the inverter system from premise wiring?Yes, as required per 230.855.   Will you be requiring an external disconnect to disconnect batteries from the inverters?Yes If the DC disconnect was not required I would not be wasting everyone’s time with my post.  I try to be careful about that, researching on my own before posting and trying to make my questions very clear.  I also try not to embarrass myself with dumb questions, but that does happen occasionally… William Miller Solar17395 Oak Road, Atascadero, CA 93422805-438-5600www.millersolar.comCA Lic. 773985  From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Glenn Burt via RE-wrenchesSent: Friday, January 27, 2023 11:46 AMTo: William Miller via RE-wrenchesCc: Glenn BurtSubject: Re: [RE-wrenches] Remote battery disconnects Does the AHJ really want the batteries disconnected from conductors, or does he really just want the inverters to stop operating and producing AC within the house?Obviously there is a big difference here and it may be changing as the code evolves. -GlennSent from my 'smart'phone, so please excuse typos and spelling errors. -- Original message--From: William Miller via RE-wrenchesDate: Fri, Jan 27, 2023 2:26 PMTo: RE-wrenches;Cc: William Miller;Subject:[RE-wrenches] Remote battery disconnects Friends: We have a large-ish residential off-grid system install coming up.  The AHJ has said they will require a remote battery disconnect.  I suspect there will be fire sprinkler controls and a pressu

Re: [RE-wrenches] Remote battery disconnects

[James Jarvis via RE-wrenches]

ing
>>>> officials, but not required, IMHO, for two reasons:  The contractor should
>>>> already be versed in the codes and, building departments can mandate their
>>>> own requirements above and beyond the code.
>>>>
>>>>
>>>>
>>>> It may seem redundant to require an AC disconnect for premise wiring as
>>>> well as a DC battery disconnect.  In most cases if you disconnect the
>>>> inverter from the batteries the AC power goes off.  However if the
>>>> generator is running at the time, some battery inverters can operate when
>>>> disconnected from batteries.  So to completely de-energize all components
>>>> of an off-grid home you need to disconnect the generator and the battery
>>>> leads.
>>>>
>>>>
>>>>
>>>> In this case the home is required to have fire sprinklers.  There is
>>>> pressure pump to provide flow to these fire sprinklers-- said pump being
>>>> powered by the inverter/battery system.  I am going to apply for a waiver
>>>> to remove the DC disconnect requirement on the grounds that the pressure
>>>> pump is essential fire suppression equipment.  Instead I will propose to
>>>> supply an AC disconnect (meeting all requirements for accessibility and
>>>> marking) that will disconnect all premise wiring except the pressure pump.
>>>>
>>>>
>>>>
>>>> By the way, I will of course be trying to apply the logic that the
>>>> voltage specification is for nominal battery voltage and this project
>>>> having a nominal 48 volt bank does not require the battery disconnect.
>>>>
>>>>
>>>>
>>>> I will let the group know what response I receive.  Regardless of how
>>>> this works in this jurisdiction, I think these are both valid arguments
>>>> worth trying in any jurisdiction requiring the battery disconnect.  Some
>>>> officials are amenable to dialog and negotiation and some are less so.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> William Miller
>>>>
>>>>
>>>>
>>>> Miller Solar
>>>>
>>>> 17395 Oak Road, Atascadero, CA 93422
>>>>
>>>> 805-438-5600
>>>>
>>>> www.millersolar.com
>>>>
>>>> CA Lic. 773985
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
>>>> Behalf Of *Jeremy Rodriguez via RE-wrenches
>>>> *Sent:* Saturday, January 28, 2023 10:12 AM
>>>> *To:* cwar...@entech-engineering.com; RE-wrenches
>>>> *Cc:* Jeremy Rodriguez
>>>> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>>>>
>>>>
>>>>
>>>> 
>>>>
>>>> *2020 Code Language:*
>>>>
>>>> *480.7 DC Disconnect Methods.*
>>>>
>>>> *(A) Disconnecting Means.* *A disconnecting means shall be provided
>>>> for all ungrounded conductors derived from a stationary battery system with
>>>> a voltage over 60 volts dc. A disconnecting means shall be readily
>>>> accessible and located within sight of the battery system.*
>>>>
>>>> *N* *(B) Emergency Disconnect.* *For one-family and two-family
>>>> dwellings, a disconnecting means or its remote control for a stationary
>>>> battery system shall be located at a readily accessible location outside
>>>> the building for emergency use. The disconnect shall be labeled “EMERGENCY
>>>> DISCONNECT”.*
>>>>
>>>> *N **(C) Disconnection of Series Battery Circuits.* *Battery circuits
>>>> exceeding 240 volts dc nominal between conductors or to ground and subject
>>>> to field servicing shall have provisions to disconnect the series-connected
>>>> strings into segments not exceeding 240 volts dc nominal for maintenance by
>>>> qualified persons. Non-load-break bolted or plug-in disconnects shall be
>>>> permitted.*
>>>>
>>>>
>>>>
>>>> Jeremy Rodriguez
>>>>
>>>> Solar Installation / Design
>>>>
>>>> All Solar, Inc.
>>>>
>>>> 1453 M St.
>>>>
>>>> Penrose Colorado 81240
>>>>
>>>>
>>>>
>>>> Sent by Jeremy's iPhone. Sorry for typos 

Re: [RE-wrenches] Remote battery disconnects

[Brian Mehalic via RE-wrenches]

Every single house I’ve looked at in my town has a breaker panel with a main service disconnect on the outside of the house already. So in many cases we are well beyond worrying about someone “flicking your switch!”In fact, in addition to the emergency disconnect requirement for stationary standby batteries [480.7(B)] and ESS [706.15(B)] in one- and two-family dwellings, also added in 2020 was the requirement for an emergency disconnect for services on those same one- and two-family dwellings [230.85]. Brian MehalicOn Jan 28, 2023, at 5:58 PM, James Jarvis via RE-wrenches  wrote:It would be nice if the decision was up to the owner / occupant of the property. I, for one, do not want any random person to be able to turn off my house or business with the flick of a switch. I feel strongly that there is far too much fear mongering in NEC with relation to renewable energy.-James Jefferson JarvisAPRS World, LLC+1-507-454-2727http://www.aprsworld.com/On Sat, Jan 28, 2023 at 6:22 PM William Miller via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote:Esteemed wrenches:Well if my house is on fire and the entry of fire responders is delayed for lack of a disconnect, I choose having the disconnect. I can worry about the charge controllers later. Others may prioritize their charge controller over their homes…Put a cable-tie lock in the closed position to discourage kids from messing with it. Test it only after dark. WilliamOn Sat, Jan 28, 2023 at 2:32 PM William Bryce <wlbr...@pineridgeproducts.com> wrote:AllOne thing that no one is talking about is what happens to the MPPT charge controllers when the Battery Disconnect trips when the charge controllers are under full load. Many will blow up. Try turning off the battery breaker on a SolaArk  when the charge controllers are maxed, and see if you get lucky.On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches <re-wrenches@lists.re-wrenches.org> wrote:Jeremy: Thanks for posting the code references for those that had never looked them up. Chris: What do you mean by “a disconnect for AC wiring, not specific to which or both panel types”? All: Code references are handy when receiving edicts from building officials, but not required, IMHO, for two reasons:  The contractor should already be versed in the codes and, building departments can mandate their own requirements above and beyond the code. It may seem redundant to require an AC disconnect for premise wiring as well as a DC battery disconnect.  In most cases if you disconnect the inverter from the batteries the AC power goes off.  However if the generator is running at the time, some battery inverters can operate when disconnected from batteries.  So to completely de-energize all components of an off-grid home you need to disconnect the generator and the battery leads. In this case the home is required to have fire sprinklers.  There is pressure pump to provide flow to these fire sprinklers-- said pump being powered by the inverter/battery system.  I am going to apply for a waiver to remove the DC disconnect requirement on the grounds that the pressure pump is essential fire suppression equipment.  Instead I will propose to supply an AC disconnect (meeting all requirements for accessibility and marking) that will disconnect all premise wiring except the pressure pump.   By the way, I will of course be trying to apply the logic that the voltage specification is for nominal battery voltage and this project having a nominal 48 volt bank does not require the battery disconnect. I will let the group know what response I receive.  Regardless of how this works in this jurisdiction, I think these are both valid arguments worth trying in any jurisdiction requiring the battery disconnect.  Some officials are amenable to dialog and negotiation and some are less so.  William Miller Miller Solar17395 Oak Road, Atascadero, CA 93422805-438-5600www.millersolar.comCA Lic. 773985  From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jeremy Rodriguez via RE-wrenchesSent: Saturday, January 28, 2023 10:12 AMTo: cwar...@entech-engineering.com; RE-wrenchesCc: Jeremy RodriguezSubject: Re: [RE-wrenches] Remote battery disconnects 2020 Code Language:480.7 DC Disconnect Methods.(A) Disconnecting Means. A disconnecting means shall be provided for all ungrounded conductors derived from a stationary battery system with a voltage over 60 volts dc. A disconnecting means shall be readily accessible and located within sight of the battery system.N (B) Emergency Disconnect. For one-family and two-family dwellings, a disconnecting means or its remote control for a stationary battery system shall be located at a readily accessible location outside the building for emergency use. The disconnect shall be labeled “EMERGENCY DISCONNECT”.N (C) Disconnection of Series Battery Circuits. Battery circuits exceeding 240 volts dc nominal between conductors or to ground and subject to field servicing sha

Re: [RE-wrenches] Remote battery disconnects

[William Miller via RE-wrenches]

James:

Your on-grid home or business already has a quick and efficient means of
disconnecting power by a random person: If you have a non-CT meter it’s a
matter of clipping the meter tag and pulling the meter. If there is a CT
meter,  there will be a switch to flip.

Fortunately off-grid homes do not usually have random people on the
premises.

I have always felt it beyond my expertise to second-guess what first
responders require  to perform their jobs safely.

Most code requirements do add expense and inconvenience. However most
requirements seem well founded in logic. When I travel in third world
countries or read about building system failures, I personally appreciate
the codes we have.

William

On Sat, Jan 28, 2023 at 4:58 PM James Jarvis  wrote:

> It would be nice if the decision was up to the owner / occupant of the
> property. I, for one, do not want any random person to be able to turn off
> my house or business with the flick of a switch. I feel strongly that there
> is far too much fear mongering in NEC with relation to renewable energy.
>
> -James Jefferson Jarvis
> APRS World, LLC
> +1-507-454-2727
> http://www.aprsworld.com/
>
>
> On Sat, Jan 28, 2023 at 6:22 PM William Miller via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>> Esteemed wrenches:
>>
>> Well if my house is on fire and the entry of fire responders is delayed
>> for lack of a disconnect, I choose having the disconnect. I can worry about
>> the charge controllers later.
>>
>> Others may prioritize their charge controller over their homes…
>>
>> Put a cable-tie lock in the closed position to discourage kids from
>> messing with it. Test it only after dark.
>>
>> William
>>
>> On Sat, Jan 28, 2023 at 2:32 PM William Bryce <
>> wlbr...@pineridgeproducts.com> wrote:
>>
>>> All
>>>
>>> One thing that no one is talking about is what happens to the MPPT
>>> charge controllers when the Battery Disconnect trips when the charge
>>> controllers are under full load.
>>> Many will blow up. Try turning off the battery breaker on a SolaArk
>>> when the charge controllers are maxed, and see if you get lucky.
>>>
>>> On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches <
>>> re-wrenches@lists.re-wrenches.org> wrote:
>>>
>>>> Jeremy:
>>>>
>>>>
>>>>
>>>> Thanks for posting the code references for those that had never looked
>>>> them up.
>>>>
>>>>
>>>>
>>>> Chris:
>>>>
>>>>
>>>>
>>>> What do you mean by “a disconnect for AC wiring, not specific to which
>>>> or both panel types”?
>>>>
>>>>
>>>>
>>>> All:
>>>>
>>>>
>>>>
>>>> Code references are handy when receiving edicts from building
>>>> officials, but not required, IMHO, for two reasons:  The contractor should
>>>> already be versed in the codes and, building departments can mandate their
>>>> own requirements above and beyond the code.
>>>>
>>>>
>>>>
>>>> It may seem redundant to require an AC disconnect for premise wiring as
>>>> well as a DC battery disconnect.  In most cases if you disconnect the
>>>> inverter from the batteries the AC power goes off.  However if the
>>>> generator is running at the time, some battery inverters can operate when
>>>> disconnected from batteries.  So to completely de-energize all components
>>>> of an off-grid home you need to disconnect the generator and the battery
>>>> leads.
>>>>
>>>>
>>>>
>>>> In this case the home is required to have fire sprinklers.  There is
>>>> pressure pump to provide flow to these fire sprinklers-- said pump being
>>>> powered by the inverter/battery system.  I am going to apply for a waiver
>>>> to remove the DC disconnect requirement on the grounds that the pressure
>>>> pump is essential fire suppression equipment.  Instead I will propose to
>>>> supply an AC disconnect (meeting all requirements for accessibility and
>>>> marking) that will disconnect all premise wiring except the pressure pump.
>>>>
>>>>
>>>>
>>>> By the way, I will of course be trying to apply the logic that the
>>>> voltage specification is for nominal battery voltage and this project
>>>> having a nominal 48 volt bank does not require the battery dis

Re: [RE-wrenches] Remote battery disconnects

[James Jarvis via RE-wrenches]

It would be nice if the decision was up to the owner / occupant of the
property. I, for one, do not want any random person to be able to turn off
my house or business with the flick of a switch. I feel strongly that there
is far too much fear mongering in NEC with relation to renewable energy.

-James Jefferson Jarvis
APRS World, LLC
+1-507-454-2727
http://www.aprsworld.com/


On Sat, Jan 28, 2023 at 6:22 PM William Miller via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Esteemed wrenches:
>
> Well if my house is on fire and the entry of fire responders is delayed
> for lack of a disconnect, I choose having the disconnect. I can worry about
> the charge controllers later.
>
> Others may prioritize their charge controller over their homes…
>
> Put a cable-tie lock in the closed position to discourage kids from
> messing with it. Test it only after dark.
>
> William
>
> On Sat, Jan 28, 2023 at 2:32 PM William Bryce <
> wlbr...@pineridgeproducts.com> wrote:
>
>> All
>>
>> One thing that no one is talking about is what happens to the MPPT charge
>> controllers when the Battery Disconnect trips when the charge controllers
>> are under full load.
>> Many will blow up. Try turning off the battery breaker on a SolaArk  when
>> the charge controllers are maxed, and see if you get lucky.
>>
>> On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches <
>> re-wrenches@lists.re-wrenches.org> wrote:
>>
>>> Jeremy:
>>>
>>>
>>>
>>> Thanks for posting the code references for those that had never looked
>>> them up.
>>>
>>>
>>>
>>> Chris:
>>>
>>>
>>>
>>> What do you mean by “a disconnect for AC wiring, not specific to which
>>> or both panel types”?
>>>
>>>
>>>
>>> All:
>>>
>>>
>>>
>>> Code references are handy when receiving edicts from building officials,
>>> but not required, IMHO, for two reasons:  The contractor should already be
>>> versed in the codes and, building departments can mandate their own
>>> requirements above and beyond the code.
>>>
>>>
>>>
>>> It may seem redundant to require an AC disconnect for premise wiring as
>>> well as a DC battery disconnect.  In most cases if you disconnect the
>>> inverter from the batteries the AC power goes off.  However if the
>>> generator is running at the time, some battery inverters can operate when
>>> disconnected from batteries.  So to completely de-energize all components
>>> of an off-grid home you need to disconnect the generator and the battery
>>> leads.
>>>
>>>
>>>
>>> In this case the home is required to have fire sprinklers.  There is
>>> pressure pump to provide flow to these fire sprinklers-- said pump being
>>> powered by the inverter/battery system.  I am going to apply for a waiver
>>> to remove the DC disconnect requirement on the grounds that the pressure
>>> pump is essential fire suppression equipment.  Instead I will propose to
>>> supply an AC disconnect (meeting all requirements for accessibility and
>>> marking) that will disconnect all premise wiring except the pressure pump.
>>>
>>>
>>>
>>> By the way, I will of course be trying to apply the logic that the
>>> voltage specification is for nominal battery voltage and this project
>>> having a nominal 48 volt bank does not require the battery disconnect.
>>>
>>>
>>>
>>> I will let the group know what response I receive.  Regardless of how
>>> this works in this jurisdiction, I think these are both valid arguments
>>> worth trying in any jurisdiction requiring the battery disconnect.  Some
>>> officials are amenable to dialog and negotiation and some are less so.
>>>
>>>
>>>
>>>
>>>
>>> William Miller
>>>
>>>
>>>
>>> Miller Solar
>>>
>>> 17395 Oak Road, Atascadero, CA 93422
>>>
>>> 805-438-5600
>>>
>>> www.millersolar.com
>>>
>>> CA Lic. 773985
>>>
>>>
>>>
>>>
>>>
>>> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
>>> Behalf Of *Jeremy Rodriguez via RE-wrenches
>>> *Sent:* Saturday, January 28, 2023 10:12 AM
>>> *To:* cwar...@entech-engineering.com; RE-wrenches
>>> *Cc:* Jeremy Rodriguez
>>> *Subject:* Re: [RE-wrenches] Remote battery di

Re: [RE-wrenches] Remote battery disconnects

[William Miller via RE-wrenches]

Esteemed wrenches:

Well if my house is on fire and the entry of fire responders is delayed for
lack of a disconnect, I choose having the disconnect. I can worry about the
charge controllers later.

Others may prioritize their charge controller over their homes…

Put a cable-tie lock in the closed position to discourage kids from messing
with it. Test it only after dark.

William

On Sat, Jan 28, 2023 at 2:32 PM William Bryce 
wrote:

> All
>
> One thing that no one is talking about is what happens to the MPPT charge
> controllers when the Battery Disconnect trips when the charge controllers
> are under full load.
> Many will blow up. Try turning off the battery breaker on a SolaArk  when
> the charge controllers are maxed, and see if you get lucky.
>
> On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>> Jeremy:
>>
>>
>>
>> Thanks for posting the code references for those that had never looked
>> them up.
>>
>>
>>
>> Chris:
>>
>>
>>
>> What do you mean by “a disconnect for AC wiring, not specific to which
>> or both panel types”?
>>
>>
>>
>> All:
>>
>>
>>
>> Code references are handy when receiving edicts from building officials,
>> but not required, IMHO, for two reasons:  The contractor should already be
>> versed in the codes and, building departments can mandate their own
>> requirements above and beyond the code.
>>
>>
>>
>> It may seem redundant to require an AC disconnect for premise wiring as
>> well as a DC battery disconnect.  In most cases if you disconnect the
>> inverter from the batteries the AC power goes off.  However if the
>> generator is running at the time, some battery inverters can operate when
>> disconnected from batteries.  So to completely de-energize all components
>> of an off-grid home you need to disconnect the generator and the battery
>> leads.
>>
>>
>>
>> In this case the home is required to have fire sprinklers.  There is
>> pressure pump to provide flow to these fire sprinklers-- said pump being
>> powered by the inverter/battery system.  I am going to apply for a waiver
>> to remove the DC disconnect requirement on the grounds that the pressure
>> pump is essential fire suppression equipment.  Instead I will propose to
>> supply an AC disconnect (meeting all requirements for accessibility and
>> marking) that will disconnect all premise wiring except the pressure pump.
>>
>>
>>
>> By the way, I will of course be trying to apply the logic that the
>> voltage specification is for nominal battery voltage and this project
>> having a nominal 48 volt bank does not require the battery disconnect.
>>
>>
>>
>> I will let the group know what response I receive.  Regardless of how
>> this works in this jurisdiction, I think these are both valid arguments
>> worth trying in any jurisdiction requiring the battery disconnect.  Some
>> officials are amenable to dialog and negotiation and some are less so.
>>
>>
>>
>>
>>
>> William Miller
>>
>>
>>
>> Miller Solar
>>
>> 17395 Oak Road, Atascadero, CA 93422
>>
>> 805-438-5600
>>
>> www.millersolar.com
>>
>> CA Lic. 773985
>>
>>
>>
>>
>>
>> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
>> Behalf Of *Jeremy Rodriguez via RE-wrenches
>> *Sent:* Saturday, January 28, 2023 10:12 AM
>> *To:* cwar...@entech-engineering.com; RE-wrenches
>> *Cc:* Jeremy Rodriguez
>> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>>
>>
>>
>> 
>>
>> *2020 Code Language:*
>>
>> *480.7 DC Disconnect Methods.*
>>
>> *(A) Disconnecting Means.* *A disconnecting means shall be provided for
>> all ungrounded conductors derived from a stationary battery system with a
>> voltage over 60 volts dc. A disconnecting means shall be readily accessible
>> and located within sight of the battery system.*
>>
>> *N* *(B) Emergency Disconnect.* *For one-family and two-family
>> dwellings, a disconnecting means or its remote control for a stationary
>> battery system shall be located at a readily accessible location outside
>> the building for emergency use. The disconnect shall be labeled “EMERGENCY
>> DISCONNECT”.*
>>
>> *N **(C) Disconnection of Series Battery Circuits.* *Battery circuits
>> exceeding 240 volts dc nominal between conductors or to ground and subject
>> to field servicin

Re: [RE-wrenches] Remote battery disconnects

[jay via RE-wrenches]

HI William B,

That is a good point.  And even beyond the potential CC damage, since your now 
potentially powering the inverter it could actually stay alive ( I’ve seen this 
happen ) or it can cause a voltage spike from the CC which can damage the  
inverter which I”ve also seen.


I don’t know what that section of the code is trying to do, but its doing it 
extremely  poorly.

jay




> On Jan 28, 2023, at 3:32 PM, William Bryce via RE-wrenches 
>  wrote:
> 
> All
> 
> One thing that no one is talking about is what happens to the MPPT charge 
> controllers when the Battery Disconnect trips when the charge controllers are 
> under full load. 
> Many will blow up. Try turning off the battery breaker on a SolaArk  when the 
> charge controllers are maxed, and see if you get lucky.
> 
> On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches 
>  <mailto:re-wrenches@lists.re-wrenches.org>> wrote:
> Jeremy:
> 
>  
> Thanks for posting the code references for those that had never looked them 
> up.
> 
>  
> Chris:
> 
>  
> What do you mean by “a disconnect for AC wiring, not specific to which or 
> both panel types”?
> 
>  
> All:
> 
>  
> Code references are handy when receiving edicts from building officials, but 
> not required, IMHO, for two reasons:  The contractor should already be versed 
> in the codes and, building departments can mandate their own requirements 
> above and beyond the code.
> 
>  
> It may seem redundant to require an AC disconnect for premise wiring as well 
> as a DC battery disconnect.  In most cases if you disconnect the inverter 
> from the batteries the AC power goes off.  However if the generator is 
> running at the time, some battery inverters can operate when disconnected 
> from batteries.  So to completely de-energize all components of an off-grid 
> home you need to disconnect the generator and the battery leads.
> 
>  
> In this case the home is required to have fire sprinklers.  There is pressure 
> pump to provide flow to these fire sprinklers-- said pump being powered by 
> the inverter/battery system.  I am going to apply for a waiver to remove the 
> DC disconnect requirement on the grounds that the pressure pump is essential 
> fire suppression equipment.  Instead I will propose to supply an AC 
> disconnect (meeting all requirements for accessibility and marking) that will 
> disconnect all premise wiring except the pressure pump. 
> 
>  
> By the way, I will of course be trying to apply the logic that the voltage 
> specification is for nominal battery voltage and this project having a 
> nominal 48 volt bank does not require the battery disconnect.
> 
>  
> I will let the group know what response I receive.  Regardless of how this 
> works in this jurisdiction, I think these are both valid arguments worth 
> trying in any jurisdiction requiring the battery disconnect.  Some officials 
> are amenable to dialog and negotiation and some are less so.
> 
>  
>  
> William Miller
> 
>  
> Miller Solar
> 
> 17395 Oak Road, Atascadero, CA 93422
> 
> 805-438-5600
> 
> www.millersolar.com <http://www.millersolar.com/>
> CA Lic. 773985
> 
>  
>  
> From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org 
> <mailto:re-wrenches-boun...@lists.re-wrenches.org>] On Behalf Of Jeremy 
> Rodriguez via RE-wrenches
> Sent: Saturday, January 28, 2023 10:12 AM
> To: cwar...@entech-engineering.com <mailto:cwar...@entech-engineering.com>; 
> RE-wrenches
> Cc: Jeremy Rodriguez
> Subject: Re: [RE-wrenches] Remote battery disconnects
> 
>  
> 
> 
> 2020 Code Language:
> 
> 480.7 DC Disconnect Methods.
> 
> (A) Disconnecting Means. A disconnecting means shall be provided for all 
> ungrounded conductors derived from a stationary battery system with a voltage 
> over 60 volts dc. A disconnecting means shall be readily accessible and 
> located within sight of the battery system.
> 
> N (B) Emergency Disconnect. For one-family and two-family dwellings, a 
> disconnecting means or its remote control for a stationary battery system 
> shall be located at a readily accessible location outside the building for 
> emergency use. The disconnect shall be labeled “EMERGENCY DISCONNECT”.
> 
> N (C) Disconnection of Series Battery Circuits. Battery circuits exceeding 
> 240 volts dc nominal between conductors or to ground and subject to field 
> servicing shall have provisions to disconnect the series-connected strings 
> into segments not exceeding 240 volts dc nominal for maintenance by qualified 
> persons. Non-load-break bolted or plug-in disconnects shall be permitted.
> 
>  
> Jeremy Rodriguez 
> 
> S

Re: [RE-wrenches] Remote battery disconnects

[William Bryce via RE-wrenches]

All

One thing that no one is talking about is what happens to the MPPT charge
controllers when the Battery Disconnect trips when the charge controllers
are under full load.
Many will blow up. Try turning off the battery breaker on a SolaArk  when
the charge controllers are maxed, and see if you get lucky.

On Sat, Jan 28, 2023 at 3:27 PM William Miller via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Jeremy:
>
>
>
> Thanks for posting the code references for those that had never looked
> them up.
>
>
>
> Chris:
>
>
>
> What do you mean by “a disconnect for AC wiring, not specific to which or
> both panel types”?
>
>
>
> All:
>
>
>
> Code references are handy when receiving edicts from building officials,
> but not required, IMHO, for two reasons:  The contractor should already be
> versed in the codes and, building departments can mandate their own
> requirements above and beyond the code.
>
>
>
> It may seem redundant to require an AC disconnect for premise wiring as
> well as a DC battery disconnect.  In most cases if you disconnect the
> inverter from the batteries the AC power goes off.  However if the
> generator is running at the time, some battery inverters can operate when
> disconnected from batteries.  So to completely de-energize all components
> of an off-grid home you need to disconnect the generator and the battery
> leads.
>
>
>
> In this case the home is required to have fire sprinklers.  There is
> pressure pump to provide flow to these fire sprinklers-- said pump being
> powered by the inverter/battery system.  I am going to apply for a waiver
> to remove the DC disconnect requirement on the grounds that the pressure
> pump is essential fire suppression equipment.  Instead I will propose to
> supply an AC disconnect (meeting all requirements for accessibility and
> marking) that will disconnect all premise wiring except the pressure pump.
>
>
>
> By the way, I will of course be trying to apply the logic that the voltage
> specification is for nominal battery voltage and this project having a
> nominal 48 volt bank does not require the battery disconnect.
>
>
>
> I will let the group know what response I receive.  Regardless of how this
> works in this jurisdiction, I think these are both valid arguments worth
> trying in any jurisdiction requiring the battery disconnect.  Some
> officials are amenable to dialog and negotiation and some are less so.
>
>
>
>
>
> William Miller
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
> Behalf Of *Jeremy Rodriguez via RE-wrenches
> *Sent:* Saturday, January 28, 2023 10:12 AM
> *To:* cwar...@entech-engineering.com; RE-wrenches
> *Cc:* Jeremy Rodriguez
> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>
>
>
> 
>
> *2020 Code Language:*
>
> *480.7 DC Disconnect Methods.*
>
> *(A) Disconnecting Means.* *A disconnecting means shall be provided for
> all ungrounded conductors derived from a stationary battery system with a
> voltage over 60 volts dc. A disconnecting means shall be readily accessible
> and located within sight of the battery system.*
>
> *N* *(B) Emergency Disconnect.* *For one-family and two-family dwellings,
> a disconnecting means or its remote control for a stationary battery system
> shall be located at a readily accessible location outside the building for
> emergency use. The disconnect shall be labeled “EMERGENCY DISCONNECT”.*
>
> *N **(C) Disconnection of Series Battery Circuits.* *Battery circuits
> exceeding 240 volts dc nominal between conductors or to ground and subject
> to field servicing shall have provisions to disconnect the series-connected
> strings into segments not exceeding 240 volts dc nominal for maintenance by
> qualified persons. Non-load-break bolted or plug-in disconnects shall be
> permitted.*
>
>
>
> Jeremy Rodriguez
>
> Solar Installation / Design
>
> All Solar, Inc.
>
> 1453 M St.
>
> Penrose Colorado 81240
>
>
>
> Sent by Jeremy's iPhone. Sorry for typos and shorthand.
>
>
>
> On Jan 28, 2023, at 7:28 AM, Christopher Warfel via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
> 
>
> Seems confusing that the AHJ is requiring a disconnect for AC wiring, not
> specific to which or both panel types, and then a dc disconnect with no
> code reference.  Was trying to convey a reasonable, safe approach.  A lot
> of bad information from fire department solar consultants making a lot of
>

Re: [RE-wrenches] Remote battery disconnects

[William Miller via RE-wrenches]

Jeremy:



Thanks for posting the code references for those that had never looked them
up.



Chris:



What do you mean by “a disconnect for AC wiring, not specific to which or
both panel types”?



All:



Code references are handy when receiving edicts from building officials,
but not required, IMHO, for two reasons:  The contractor should already be
versed in the codes and, building departments can mandate their own
requirements above and beyond the code.



It may seem redundant to require an AC disconnect for premise wiring as
well as a DC battery disconnect.  In most cases if you disconnect the
inverter from the batteries the AC power goes off.  However if the
generator is running at the time, some battery inverters can operate when
disconnected from batteries.  So to completely de-energize all components
of an off-grid home you need to disconnect the generator and the battery
leads.



In this case the home is required to have fire sprinklers.  There is
pressure pump to provide flow to these fire sprinklers-- said pump being
powered by the inverter/battery system.  I am going to apply for a waiver
to remove the DC disconnect requirement on the grounds that the pressure
pump is essential fire suppression equipment.  Instead I will propose to
supply an AC disconnect (meeting all requirements for accessibility and
marking) that will disconnect all premise wiring except the pressure pump.



By the way, I will of course be trying to apply the logic that the voltage
specification is for nominal battery voltage and this project having a
nominal 48 volt bank does not require the battery disconnect.



I will let the group know what response I receive.  Regardless of how this
works in this jurisdiction, I think these are both valid arguments worth
trying in any jurisdiction requiring the battery disconnect.  Some
officials are amenable to dialog and negotiation and some are less so.





William Miller



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
Behalf Of *Jeremy Rodriguez via RE-wrenches
*Sent:* Saturday, January 28, 2023 10:12 AM
*To:* cwar...@entech-engineering.com; RE-wrenches
*Cc:* Jeremy Rodriguez
*Subject:* Re: [RE-wrenches] Remote battery disconnects





*2020 Code Language:*

*480.7 DC Disconnect Methods.*

*(A) Disconnecting Means.* *A disconnecting means shall be provided for all
ungrounded conductors derived from a stationary battery system with a
voltage over 60 volts dc. A disconnecting means shall be readily accessible
and located within sight of the battery system.*

*N* *(B) Emergency Disconnect.* *For one-family and two-family dwellings, a
disconnecting means or its remote control for a stationary battery system
shall be located at a readily accessible location outside the building for
emergency use. The disconnect shall be labeled “EMERGENCY DISCONNECT”.*

*N **(C) Disconnection of Series Battery Circuits.* *Battery circuits
exceeding 240 volts dc nominal between conductors or to ground and subject
to field servicing shall have provisions to disconnect the series-connected
strings into segments not exceeding 240 volts dc nominal for maintenance by
qualified persons. Non-load-break bolted or plug-in disconnects shall be
permitted.*



Jeremy Rodriguez

Solar Installation / Design

All Solar, Inc.

1453 M St.

Penrose Colorado 81240



Sent by Jeremy's iPhone. Sorry for typos and shorthand.



On Jan 28, 2023, at 7:28 AM, Christopher Warfel via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:



Seems confusing that the AHJ is requiring a disconnect for AC wiring, not
specific to which or both panel types, and then a dc disconnect with no
code reference.  Was trying to convey a reasonable, safe approach.  A lot
of bad information from fire department solar consultants making a lot of
money fear mongering, which has led to this type of situation.  Chris

On 1/27/2023 3:35 PM, William Miller via RE-wrenches wrote:

Glenn:



As I wrote, a DC disconnect is required.  Here is an excerpt from the Q
with the building official:



4.   Will you be requiring an external disconnect to disconnect the AC
output of the inverter system from premise wiring?

Yes, as required per 230.85

5.   Will you be requiring an external disconnect to disconnect batteries
from the inverters?

Yes



If the DC disconnect was not required I would not be wasting everyone’s
time with my post.  I try to be careful about that, researching on my own
before posting and trying to make my questions very clear.  I also try not
to embarrass myself with dumb questions, but that does happen occasionally…



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
Behalf Of *Glenn Burt via RE-wrenches
*Sent:* Friday, January 27, 2023 11

Re: [RE-wrenches] Remote battery disconnects

[Kirk Herander via RE-wrenches]

A dc-rated shunt trip breaker @ 250A (Blue Planet / OB Radian cabinet
breaker) would do the trick if they exist. The trip device could be mounted
outside.

On Fri, Jan 27, 2023 at 3:55 PM William Miller via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Glenn:
>
>
>
> As I wrote, a DC disconnect is required.  Here is an excerpt from the Q
> with the building official:
>
>
>
> 4.   Will you be requiring an external disconnect to disconnect the AC
> output of the inverter system from premise wiring?
>
> Yes, as required per 230.85
>
> 5.   Will you be requiring an external disconnect to disconnect batteries
> from the inverters?
>
> Yes
>
>
>
> If the DC disconnect was not required I would not be wasting everyone’s
> time with my post.  I try to be careful about that, researching on my own
> before posting and trying to make my questions very clear.  I also try not
> to embarrass myself with dumb questions, but that does happen occasionally…
>
>
>
> William
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
> Behalf Of *Glenn Burt via RE-wrenches
> *Sent:* Friday, January 27, 2023 11:46 AM
> *To:* William Miller via RE-wrenches
> *Cc:* Glenn Burt
> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>
>
>
> Does the AHJ really want the batteries disconnected from conductors, or
> does he really just want the inverters to stop operating and producing AC
> within the house?
>
> Obviously there is a big difference here and it may be changing as the
> code evolves.
>
>
>
> -Glenn
>
> Sent from my 'smart'phone, so please excuse typos and spelling errors.
>
>
>
> -- Original message--
>
> *From: *William Miller via RE-wrenches
>
> *Date: *Fri, Jan 27, 2023 2:26 PM
>
> *To: *RE-wrenches;
>
> *Cc: *William Miller;
>
> *Subject:*[RE-wrenches] Remote battery disconnects
>
>
>
> Friends:
>
>
>
> We have a large-ish residential off-grid system install coming up.  The
> AHJ has said they will require a remote battery disconnect.  I suspect
> there will be fire sprinkler controls and a pressure pump that would become
> inoperable if this system were engaged.  In this case we will apply for a
> waiver.
>
>
>
> The last time this was discussed here as far as I can find was October of
> 2020.  At that time no one suggested any specific battery disconnect
> equipment.
>
>
>
> To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters
> (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner
> outputs.  That is 6 poles of high amperage DC disconnects.
>
>
>
> The battery array will be either a UnigyII VRLA or a lithium of a brand
> yet to be determined.  In the case of lithium we will look for a system
> that can remotely enable a BMS shutdown.  In the case of a VRLA lead-acid,
> we will not have that luxury.
>
>
>
> I have done some considerable research and have not found viable, high
> amperage, remotely activated shutdown equipment.
>
>
>
> I am wondering what hardware others may be using to achieve remote battery
> disconnecting in these types of cases..
>
>
>
> William
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches@lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
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-- 

*Kirk Herander / **kirkh@vermont.solar *

*Owner|Principal, VT Solar, LLC*

*Celebrating our 32st Anniversary 1991-2023!!*

dba Vermont Solar Engineering

802.863.1202
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Re: [RE-wrenches] Remote battery disconnects

[Jeremy Rodriguez via RE-wrenches]



2020 Code Language:

480.7 DC Disconnect Methods.

(A) Disconnecting Means. A disconnecting means shall be provided for all 
ungrounded conductors derived from a stationary battery system with a voltage 
over 60 volts dc. A disconnecting means shall be readily accessible and located 
within sight of the battery system.

N (B) Emergency Disconnect. For one-family and two-family dwellings, a 
disconnecting means or its remote control for a stationary battery system shall 
be located at a readily accessible location outside the building for emergency 
use. The disconnect shall be labeled “EMERGENCY DISCONNECT”.

N (C) Disconnection of Series Battery Circuits. Battery circuits exceeding 240 
volts dc nominal between conductors or to ground and subject to field servicing 
shall have provisions to disconnect the series-connected strings into segments 
not exceeding 240 volts dc nominal for maintenance by qualified persons. 
Non-load-break bolted or plug-in disconnects shall be permitted.

Jeremy Rodriguez
Solar Installation / Design
All Solar, Inc.
1453 M St.
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.

On Jan 28, 2023, at 7:28 AM, Christopher Warfel via RE-wrenches 
 wrote:



Seems confusing that the AHJ is requiring a disconnect for AC wiring, not 
specific to which or both panel types, and then a dc disconnect with no code 
reference.  Was trying to convey a reasonable, safe approach.  A lot of bad 
information from fire department solar consultants making a lot of money fear 
mongering, which has led to this type of situation.  Chris

On 1/27/2023 3:35 PM, William Miller via RE-wrenches wrote:
Glenn:

As I wrote, a DC disconnect is required.  Here is an excerpt from the Q with 
the building official:


4.   Will you be requiring an external disconnect to disconnect the AC output 
of the inverter system from premise wiring?

Yes, as required per 230.85

5.   Will you be requiring an external disconnect to disconnect batteries from 
the inverters?

Yes

If the DC disconnect was not required I would not be wasting everyone’s time 
with my post.  I try to be careful about that, researching on my own before 
posting and trying to make my questions very clear.  I also try not to 
embarrass myself with dumb questions, but that does happen occasionally…

William

Miller Solar
17395 Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com<http://www.millersolar.com/>
CA Lic. 773985


From: RE-wrenches 
[mailto:re-wrenches-boun...@lists.re-wrenches.org<mailto:re-wrenches-boun...@lists.re-wrenches.org>]
 On Behalf Of Glenn Burt via RE-wrenches
Sent: Friday, January 27, 2023 11:46 AM
To: William Miller via RE-wrenches
Cc: Glenn Burt
Subject: Re: [RE-wrenches] Remote battery disconnects

Does the AHJ really want the batteries disconnected from conductors, or does he 
really just want the inverters to stop operating and producing AC within the 
house?
Obviously there is a big difference here and it may be changing as the code 
evolves.

-Glenn
Sent from my 'smart'phone, so please excuse typos and spelling errors.

-- Original message--
From: William Miller via RE-wrenches
Date: Fri, Jan 27, 2023 2:26 PM
To: RE-wrenches;
Cc: William Miller;
Subject:[RE-wrenches] Remote battery disconnects

Friends:

We have a large-ish residential off-grid system install coming up.  The AHJ has 
said they will require a remote battery disconnect.  I suspect there will be 
fire sprinkler controls and a pressure pump that would become inoperable if 
this system were engaged.  In this case we will apply for a waiver.

The last time this was discussed here as far as I can find was October of 2020. 
 At that time no one suggested any specific battery disconnect equipment.

To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters (5 or 
6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner outputs.  
That is 6 poles of high amperage DC disconnects.

The battery array will be either a UnigyII VRLA or a lithium of a brand yet to 
be determined.  In the case of lithium we will look for a system that can 
remotely enable a BMS shutdown.  In the case of a VRLA lead-acid, we will not 
have that luxury.

I have done some considerable research and have not found viable, high 
amperage, remotely activated shutdown equipment.

I am wondering what hardware others may be using to achieve remote battery 
disconnecting in these types of cases..

William

Miller Solar
17395 Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com<http://www.millersolar.com/>
CA Lic. 773985





___
List sponsored by Redwood Alliance

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There are two list arch

Re: [RE-wrenches] Remote battery disconnects

[Christopher Warfel via RE-wrenches]

Seems confusing that the AHJ is requiring a disconnect for AC wiring, 
not specific to which or both panel types, and then a dc disconnect with 
no code reference.  Was trying to convey a reasonable, safe approach.  A 
lot of bad information from fire department solar consultants making a 
lot of money fear mongering, which has led to this type of situation.  Chris


On 1/27/2023 3:35 PM, William Miller via RE-wrenches wrote:


Glenn:

As I wrote, a DC disconnect is required.  Here is an excerpt from the 
Q with the building official:


4.Will you be requiring an external disconnect to disconnect the AC 
output of the inverter system from premise wiring?


Yes, as required per 230.85

5.Will you be requiring an external disconnect to disconnect batteries 
from the inverters?


Yes

If the DC disconnect was not required I would not be wasting 
everyone’s time with my post.  I try to be careful about that, 
researching on my own before posting and trying to make my questions 
very clear.  I also try not to embarrass myself with dumb questions, 
but that does happen occasionally…


William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] 
*On Behalf Of *Glenn Burt via RE-wrenches

*Sent:* Friday, January 27, 2023 11:46 AM
*To:* William Miller via RE-wrenches
*Cc:* Glenn Burt
*Subject:* Re: [RE-wrenches] Remote battery disconnects

Does the AHJ really want the batteries disconnected from conductors, 
or does he really just want the inverters to stop operating and 
producing AC within the house?


Obviously there is a big difference here and it may be changing as the 
code evolves.


-Glenn

Sent from my 'smart'phone, so please excuse typos and spelling errors.

-- Original message--

*From: *William Miller via RE-wrenches

*Date: *Fri, Jan 27, 2023 2:26 PM

*To: *RE-wrenches;

*Cc: *William Miller;

*Subject:*[RE-wrenches] Remote battery disconnects

Friends:

We have a large-ish residential off-grid system install coming up.  
The AHJ has said they will require a remote battery disconnect.  I 
suspect there will be fire sprinkler controls and a pressure pump that 
would become inoperable if this system were engaged.  In this case we 
will apply for a waiver.


The last time this was discussed here as far as I can find was October 
of 2020.  At that time no one suggested any specific battery 
disconnect equipment.


To further clarify my needs:  There will be 4 or 5 Radian 8048 
inverters (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV 
recombiner outputs.  That is 6 poles of high amperage DC disconnects.


The battery array will be either a UnigyII VRLA or a lithium of a 
brand yet to be determined.  In the case of lithium we will look for a 
system that can remotely enable a BMS shutdown.  In the case of a VRLA 
lead-acid, we will not have that luxury.


I have done some considerable research and have not found viable, high 
amperage, remotely activated shutdown equipment.


I am wondering what hardware others may be using to achieve remote 
battery disconnecting in these types of cases..


William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600 

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985


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--
            Christopher Warfel
                 ENTECH Engineering, Inc.
PO Box 871, Block Island, RI 02807
                                401-466-8978
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Re: [RE-wrenches] Remote battery disconnects

[Mac Lewis via RE-wrenches]

Hi William,

Keep in mind that the bigger Midnite remote trip breakers aren't UL listed
last I checked.

Let us know what you come up with.



On Fri, Jan 27, 2023 at 2:39 PM Bradley Bassett via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Wiliam,
>
> I designed a system for this using the MidNite RT breakers. They use 24VDC
> to trigger them, but you must then open the 24VDC to them once they have
> tripped or it will burn out the coil in the breaker. What I designed was a
> 48VDC to 24VDC power supply and a EPO button that is normally open. We have
> both of these, the N.O. button is rare. The power supply is from OutBack.
> Then once the breaker has tripped the power is no longer supplied to the
> switch or RT breaker. It does require a manual reset of the breaker. I've
> attached a drawing of this.
>
> Brad
> AEE Solar
>
> On Fri, Jan 27, 2023 at 12:54 PM William Miller via RE-wrenches <
> re-wrenches@lists.re-wrenches.org> wrote:
>
>> Glenn:
>>
>>
>>
>> As I wrote, a DC disconnect is required.  Here is an excerpt from the Q
>> with the building official:
>>
>>
>>
>> 4.   Will you be requiring an external disconnect to disconnect the AC
>> output of the inverter system from premise wiring?
>>
>> Yes, as required per 230.85
>>
>> 5.   Will you be requiring an external disconnect to disconnect
>> batteries from the inverters?
>>
>> Yes
>>
>>
>>
>> If the DC disconnect was not required I would not be wasting everyone’s
>> time with my post.  I try to be careful about that, researching on my own
>> before posting and trying to make my questions very clear.  I also try not
>> to embarrass myself with dumb questions, but that does happen occasionally…
>>
>>
>>
>> William
>>
>>
>>
>> Miller Solar
>>
>> 17395 Oak Road, Atascadero, CA 93422
>>
>> 805-438-5600
>>
>> www.millersolar.com
>>
>> CA Lic. 773985
>>
>>
>>
>>
>>
>> *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
>> Behalf Of *Glenn Burt via RE-wrenches
>> *Sent:* Friday, January 27, 2023 11:46 AM
>> *To:* William Miller via RE-wrenches
>> *Cc:* Glenn Burt
>> *Subject:* Re: [RE-wrenches] Remote battery disconnects
>>
>>
>>
>> Does the AHJ really want the batteries disconnected from conductors, or
>> does he really just want the inverters to stop operating and producing AC
>> within the house?
>>
>> Obviously there is a big difference here and it may be changing as the
>> code evolves.
>>
>>
>>
>> -Glenn
>>
>> Sent from my 'smart'phone, so please excuse typos and spelling errors.
>>
>>
>>
>> -- Original message--
>>
>> *From: *William Miller via RE-wrenches
>>
>> *Date: *Fri, Jan 27, 2023 2:26 PM
>>
>> *To: *RE-wrenches;
>>
>> *Cc: *William Miller;
>>
>> *Subject:*[RE-wrenches] Remote battery disconnects
>>
>>
>>
>> Friends:
>>
>>
>>
>> We have a large-ish residential off-grid system install coming up.  The
>> AHJ has said they will require a remote battery disconnect.  I suspect
>> there will be fire sprinkler controls and a pressure pump that would become
>> inoperable if this system were engaged.  In this case we will apply for a
>> waiver.
>>
>>
>>
>> The last time this was discussed here as far as I can find was October of
>> 2020.  At that time no one suggested any specific battery disconnect
>> equipment.
>>
>>
>>
>> To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters
>> (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner
>> outputs.  That is 6 poles of high amperage DC disconnects.
>>
>>
>>
>> The battery array will be either a UnigyII VRLA or a lithium of a brand
>> yet to be determined.  In the case of lithium we will look for a system
>> that can remotely enable a BMS shutdown.  In the case of a VRLA lead-acid,
>> we will not have that luxury.
>>
>>
>>
>> I have done some considerable research and have not found viable, high
>> amperage, remotely activated shutdown equipment.
>>
>>
>>
>> I am wondering what hardware others may be using to achieve remote
>> battery disconnecting in these types of cases..
>>
>>
>>
>> William
>>
>>
>>
>> Miller Solar
>>
>> 17395 Oak Road, Atascadero, CA 93422
>>
>> 805

Re: [RE-wrenches] Remote battery disconnects

[William Miller via RE-wrenches]

Glenn:



As I wrote, a DC disconnect is required.  Here is an excerpt from the Q
with the building official:



4.   Will you be requiring an external disconnect to disconnect the AC
output of the inverter system from premise wiring?

Yes, as required per 230.85

5.   Will you be requiring an external disconnect to disconnect batteries
from the inverters?

Yes



If the DC disconnect was not required I would not be wasting everyone’s
time with my post.  I try to be careful about that, researching on my own
before posting and trying to make my questions very clear.  I also try not
to embarrass myself with dumb questions, but that does happen occasionally…



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985





*From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On
Behalf Of *Glenn Burt via RE-wrenches
*Sent:* Friday, January 27, 2023 11:46 AM
*To:* William Miller via RE-wrenches
*Cc:* Glenn Burt
*Subject:* Re: [RE-wrenches] Remote battery disconnects



Does the AHJ really want the batteries disconnected from conductors, or
does he really just want the inverters to stop operating and producing AC
within the house?

Obviously there is a big difference here and it may be changing as the code
evolves.



-Glenn

Sent from my 'smart'phone, so please excuse typos and spelling errors.



-- Original message--

*From: *William Miller via RE-wrenches

*Date: *Fri, Jan 27, 2023 2:26 PM

*To: *RE-wrenches;

*Cc: *William Miller;

*Subject:*[RE-wrenches] Remote battery disconnects



Friends:



We have a large-ish residential off-grid system install coming up.  The AHJ
has said they will require a remote battery disconnect.  I suspect there
will be fire sprinkler controls and a pressure pump that would become
inoperable if this system were engaged.  In this case we will apply for a
waiver.



The last time this was discussed here as far as I can find was October of
2020.  At that time no one suggested any specific battery disconnect
equipment.



To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters (5
or 6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner
outputs.  That is 6 poles of high amperage DC disconnects.



The battery array will be either a UnigyII VRLA or a lithium of a brand yet
to be determined.  In the case of lithium we will look for a system that
can remotely enable a BMS shutdown.  In the case of a VRLA lead-acid, we
will not have that luxury.



I have done some considerable research and have not found viable, high
amperage, remotely activated shutdown equipment.



I am wondering what hardware others may be using to achieve remote battery
disconnecting in these types of cases..



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985
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Re: [RE-wrenches] Remote battery disconnects

[Jeremy Rodriguez via RE-wrenches]

I believe midnite still has the remote trip DC PNL  mount breakers, but of 
course, no birdhouse to make it work.
Not sure what the trip trigger needs either as far as voltage.

-MNEDC250RT

Jeremy Rodriguez
Solar Installation / Design
All Solar, Inc.
1453 M St.
Penrose Colorado 81240

Sent by Jeremy's iPhone. Sorry for typos and shorthand.

On Jan 27, 2023, at 12:26 PM, William Miller via RE-wrenches 
 wrote:


Friends:

We have a large-ish residential off-grid system install coming up.  The AHJ has 
said they will require a remote battery disconnect.  I suspect there will be 
fire sprinkler controls and a pressure pump that would become inoperable if 
this system were engaged.  In this case we will apply for a waiver.

The last time this was discussed here as far as I can find was October of 2020. 
 At that time no one suggested any specific battery disconnect equipment.

To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters (5 or 
6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner outputs.  
That is 6 poles of high amperage DC disconnects.

The battery array will be either a UnigyII VRLA or a lithium of a brand yet to 
be determined.  In the case of lithium we will look for a system that can 
remotely enable a BMS shutdown.  In the case of a VRLA lead-acid, we will not 
have that luxury.

I have done some considerable research and have not found viable, high 
amperage, remotely activated shutdown equipment.

I am wondering what hardware others may be using to achieve remote battery 
disconnecting in these types of cases..

William

Miller Solar
17395 Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com
CA Lic. 773985


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Re: [RE-wrenches] Remote battery disconnects

[Christopher Warfel via RE-wrenches]

This was my first thought too.  An ac disconnect that is readily 
available that controls the ac conductors to the back up loads panel(s) 
would be less dangerous and has much less worries about it failing.  Chris


On 1/27/2023 2:45 PM, Glenn Burt via RE-wrenches wrote:
Does the AHJ really want the batteries disconnected from conductors, 
or does he really just want the inverters to stop operating and 
producing AC within the house?
Obviously there is a big difference here and it may be changing as the 
code evolves.


-Glenn
Sent from my 'smart'phone, so please excuse typos and spelling errors.

-- Original message--
*From: *William Miller via RE-wrenches
*Date: *Fri, Jan 27, 2023 2:26 PM
*To: *RE-wrenches;
*Cc: *William Miller;
*Subject:*[RE-wrenches] Remote battery disconnects

Friends:

We have a large-ish residential off-grid system install coming up.  
The AHJ has said they will require a remote battery disconnect.  I 
suspect there will be fire sprinkler controls and a pressure pump that 
would become inoperable if this system were engaged.  In this case we 
will apply for a waiver.


The last time this was discussed here as far as I can find was October 
of 2020.  At that time no one suggested any specific battery 
disconnect equipment.


To further clarify my needs:  There will be 4 or 5 Radian 8048 
inverters (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV 
recombiner outputs.  That is 6 poles of high amperage DC disconnects.


The battery array will be either a UnigyII VRLA or a lithium of a 
brand yet to be determined.  In the case of lithium we will look for a 
system that can remotely enable a BMS shutdown.  In the case of a VRLA 
lead-acid, we will not have that luxury.


I have done some considerable research and have not found viable, high 
amperage, remotely activated shutdown equipment.


I am wondering what hardware others may be using to achieve remote 
battery disconnecting in these types of cases..


William

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600 

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985


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--
            Christopher Warfel
                 ENTECH Engineering, Inc.
PO Box 871, Block Island, RI 02807
                                401-466-8978
<http://entech-engineering.com>

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Re: [RE-wrenches] Remote battery disconnects

[Jerry Shafer via RE-wrenches]

William
We have done 80 kwh Blue planet resi installs in the past (at the time this
was as large as we could go in resi) anyway the BMS has a push to start and
on/off buttons we just connected into them and we compliant, rotory switch
at 24 volts 10 mA is all that is needed, Now not all BMS.s can do this so
verify first, Fortress has a start up button but I am not sure if it is
serviceable like blue planet is.
Jerry

On Fri, Jan 27, 2023 at 11:26 AM William Miller via RE-wrenches <
re-wrenches@lists.re-wrenches.org> wrote:

> Friends:
>
>
>
> We have a large-ish residential off-grid system install coming up.  The
> AHJ has said they will require a remote battery disconnect.  I suspect
> there will be fire sprinkler controls and a pressure pump that would become
> inoperable if this system were engaged.  In this case we will apply for a
> waiver.
>
>
>
> The last time this was discussed here as far as I can find was October of
> 2020.  At that time no one suggested any specific battery disconnect
> equipment.
>
>
>
> To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters
> (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner
> outputs.  That is 6 poles of high amperage DC disconnects.
>
>
>
> The battery array will be either a UnigyII VRLA or a lithium of a brand
> yet to be determined.  In the case of lithium we will look for a system
> that can remotely enable a BMS shutdown.  In the case of a VRLA lead-acid,
> we will not have that luxury.
>
>
>
> I have done some considerable research and have not found viable, high
> amperage, remotely activated shutdown equipment.
>
>
>
> I am wondering what hardware others may be using to achieve remote battery
> disconnecting in these types of cases..
>
>
>
> William
>
>
>
> Miller Solar
>
> 17395 Oak Road, Atascadero, CA 93422
>
> 805-438-5600
>
> www.millersolar.com
>
> CA Lic. 773985
>
>
>
>
> ___
> List sponsored by Redwood Alliance
>
> Pay optional member dues here: http://re-wrenches.org
>
> List Address: RE-wrenches@lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
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> other:
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Re: [RE-wrenches] Remote battery disconnects

[Jay via RE-wrenches]

Good point Glenn. My question is if this system is in its own building. If so it is probably easier to convince the AHJ about not needing a remote battery disco. JayOn Jan 27, 2023, at 12:46 PM, Glenn Burt via RE-wrenches  wrote:








Does the AHJ really want the batteries disconnected from conductors, or does he really just want the inverters to stop operating and producing AC within the house?Obviously there is a big difference here and it may be changing as the code evolves.-GlennSent from my 'smart'phone, so please excuse typos and spelling errors.-- Original message--From: William Miller via RE-wrenchesDate: Fri, Jan 27, 2023 2:26 PMTo: RE-wrenches;Cc: William
 Miller;Subject:[RE-wrenches] Remote battery disconnectsFriends: We have a large-ish residential off-grid system install coming up.  The AHJ has said they will require a remote battery disconnect.  I suspect there will be fire sprinkler controls and a pressure pump that would become inoperable if this system were engaged.  In this case we will apply for a waiver. The last time this was discussed here as far as I can find was October of 2020.  At that time no one suggested any specific battery disconnect equipment.   To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters (5 or 6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner outputs.  That is 6 poles of high amperage DC disconnects.     The battery array will be either a
 UnigyII VRLA or a lithium of a brand yet to be determined.  In the case of lithium we will look for a system that can remotely enable a BMS shutdown.  In the case of a VRLA lead-acid, we will not have that luxury. I have done some considerable research and have not found viable, high amperage, remotely activated shutdown equipment. I am wondering what hardware others may be using to achieve remote battery disconnecting in these types of cases.. William Miller Solar17395 Oak Road, Atascadero, CA 93422805-438-5600www.millersolar.comCA Lic. 773985  


___List sponsored by Redwood AlliancePay optional member dues here: http://re-wrenches.orgList Address: RE-wrenches@lists.re-wrenches.orgChange listserver email address & settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.orgThere are two list archives for searching. When one doesn't work, try the other:https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.orgList rules & etiquette:http://www.re-wrenches.org/etiquette.htmCheck out or update participant bios:http://www.members.re-wrenches.org___
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Re: [RE-wrenches] Remote battery disconnects

[Glenn Burt via RE-wrenches]

Does the AHJ really want the batteries disconnected from conductors, or does he 
really just want the inverters to stop operating and producing AC within the 
house?Obviously there is a big difference here and it may be changing as the 
code evolves.-GlennSent from my 'smart'phone, so please excuse typos and 
spelling errors.-- Original message--From: William Miller via 
RE-wrenchesDate: Fri, Jan 27, 2023 2:26 PMTo: RE-wrenches;Cc: William 
Miller;Subject:[RE-wrenches] Remote battery disconnectsFriends: We have a 
large-ish residential off-grid system install coming up.  The AHJ has said they 
will require a remote battery disconnect.  I suspect there will be fire 
sprinkler controls and a pressure pump that would become inoperable if this 
system were engaged.  In this case we will apply for a waiver. The last time 
this was discussed here as far as I can find was October of 2020.  At that time 
no one suggested any specific battery disconnect equipment.   To further 
clarify my 
 needs: 
 There will be 4 or 5 Radian 8048 inverters (5 or 6 4/0 battery circuits, ~350A 
each) and two 175 amp PV recombiner outputs.  That is 6 poles of high amperage 
DC disconnects.     The battery array will be either a UnigyII VRLA or a 
lithium of a brand yet to be determined.  In the case of lithium we will look 
for a system that can remotely enable a BMS shutdown.  In the case of a VRLA 
lead-acid, we will not have that luxury. I have done some considerable research 
and have not found viable, high amperage, remotely activated shutdown 
equipment. I am wondering what hardware others may be using to achieve remote 
battery disconnecting in these types of cases.. William Miller Solar17395 Oak 
Road, Atascadero, CA 93422805-438-5600www.millersolar.comCA Lic. 773985  ___
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[RE-wrenches] Remote battery disconnects

[William Miller via RE-wrenches]

Friends:



We have a large-ish residential off-grid system install coming up.  The AHJ
has said they will require a remote battery disconnect.  I suspect there
will be fire sprinkler controls and a pressure pump that would become
inoperable if this system were engaged.  In this case we will apply for a
waiver.



The last time this was discussed here as far as I can find was October of
2020.  At that time no one suggested any specific battery disconnect
equipment.



To further clarify my needs:  There will be 4 or 5 Radian 8048 inverters (5
or 6 4/0 battery circuits, ~350A each) and two 175 amp PV recombiner
outputs.  That is 6 poles of high amperage DC disconnects.



The battery array will be either a UnigyII VRLA or a lithium of a brand yet
to be determined.  In the case of lithium we will look for a system that
can remotely enable a BMS shutdown.  In the case of a VRLA lead-acid, we
will not have that luxury.



I have done some considerable research and have not found viable, high
amperage, remotely activated shutdown equipment.



I am wondering what hardware others may be using to achieve remote battery
disconnecting in these types of cases..



William



Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com

CA Lic. 773985
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