Re: [RE-wrenches] Small battery bank vs too large array

[Chris Mason]

I did a similar system for a client, in a place where grid connections were
not very legal. We powered s sub-panel but the power exported was used in
the rest of the house.
If you use 4 x 250Ah batteries, a 60A controller is not going to over
charge the batteries as they have a 65A charging limit so you don't need to
get into homegrown solutions.
2KW PV will only give you 40A @ 50V
The system will send the excess to the grid (We did grid tie).
The grid will take over if you have an outage.
The system will revert to grid once the battery level falls below a setting
- we used 44V.
It works well and is inexpensive to do.



On Thu, Jul 19, 2012 at 5:20 PM, Drake  wrote:

>  Hello Wrenches,
>
> Where can I get a device that will measure current through a shunt and
> create a signal to trigger a relay?
>
> We want to be able to use a 2 kW array with four, 200 AH sealed batteries
> on an Outback system.  2 kW of PV would be too much amperage for the
> batteries.  The idea is to open relays to disengage strings in conditions
> of high current to the batteries.
>
> The reason for this is to create backup systems where power will be
> abundantly available when the sun shines. The system will normally connect
> to the grid, except during outages.  In normal charging conditions the
> power will go straight to the grid.  When the grid is down, power will be
> available for loads and battery charging, but batteries will be protected
> from overcharge?
>
> Any suggestions on ways to accomplish this are welcome!
>
> Thanks
>
> Drake
>
>
> Drake Chamberlin
> *Athens Electric LLC
> OH License 44810
> CO License 3773
> NABCEP Certified Solar PV Installer
> 740-448-7328
> *http://athens-electric.com/
>
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-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com
Cell: 264.235.5670
Skype: netconcepts
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Re: [RE-wrenches] mounting hardware and U.L.

[Chris Mason]

PV installations are governed by the NEC as electrical systems, the
mounting system is not electrical and would not be required to be UL listed.

On Thu, Jul 19, 2012 at 6:36 PM, Marco Mangelsdorf wrote:

>  Does anyone know whether there are U.L. standards when it comes to PV
> mounting hardware?
>
> ** **
>
> That is, are there any mounting hardware manufacturers (UniRac,
> Professional Solar Products, DPW, Schletter) who have achieved U.L.
> listing/approval for their stuff?
>
> ** **
>
> After using PSP for the past 12 years here on the Big Island of Hawaii,
> now, all of a sudden the new building division head is taking an interest
> as to whether PSP hardware is U.L. something or other.
>
> ** **
>
> So very frustrating
>
> ** **
>
> Thanks,
>
> marco
>
> ** **
>
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-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com
Cell: 264.235.5670
Skype: netconcepts
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Re: [RE-wrenches] Small battery bank vs too large array

[Drake]

Thank you Phil,

That is the solution.  Your wealth of knowledge has proven itself again.

Drake

At 12:34 AM 7/20/2012, you wrote:

OutBack implemented Global Charge Control in the FM charge controllers
a while back, based on the input of the good folk at SELF who worked
to power a number of hospitals and clinics in Haiti after the
earthquake.  In some of those systems, the PV array was based on the
typical running consumption of the hospital, in the 30 - 100 kW if I
remember right, and the battery bank was relatively modest. However,
on the weekends and holidays without the normal AC loads the PV input
was considerably more than the battery could absorb without
destructive heating, something like a C2 or C5 rate.

Global Charge Control is implemented using the MATE3, a FN-DC and FM
charge controllers set to GT mode.  You set a high charge current
limit in the M3, and then it monitors the charge current going to the
batteries.  In normal operating mode the controllers stay in wide open
mode, harvesting as much power as possible.  However if the loads drop
and the total current from the charging sources begin exceed the
global charge limit, the system compensates and the controllers back
off to prevent sending too much current to the batteries.

In today's world of PV modules being cheaper than diesel, we're seeing
a lot more systems that can use this tool.

Hope this helps,

Phil



On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com
 wrote:
>
>
> I didn't see that Brian T had the same idea until after I sent that email
> off to Allan...
> boB
>
>
>
>
>
> On 7/19/2012 7:53 PM, Allan Sindelar wrote:
>
> Wrenches,
> I forwarded Brian's post on to Robin at Midnite, as I thought it was an
> interesting idea. Below is his response, as well as boB's.
> Allan
>
> Allan Sindelar
> al...@positiveenergysolar.com
> NABCEP Certified Photovoltaic Installer
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> Founder and Chief Technology Officer
> Positive Energy, Inc.
> 3209 Richards Lane (note new address)
> Santa Fe, New Mexico 87507
> 505 424-1112
> www.positiveenergysolar.com
>
> Allan, It is simpler than what is being suggested. The reason they want to
> limit to 20 amps is because the battery doesn’t need anymore than that. The
> controller will automatically limit the charge current as the battery gets
> full. If a large load is turned on, the controller will try to refill the
> battery up to its capacity. The 80 amps will quickly be reduced because the
> voltage will rise to the point where the charge tapers off.
>
> There is nothing else that needs to be done. If the problem is that the
> battery bank is too small for a big controller, the best answer is to get
> more batteries. A 80 amp charger into a 200 amp hour battery is going to
> raise the battery voltage so quick, it will not affect the battery at all.
> By the way, discharging a battery at 60 or 80 amps is probably going to do
> damage to a small battery also. We do have an input on the Classic that
> could probably be programmed to do as requested. That input feature has yet
> to be implemented. I’m sure we will have discussions about this when the
> time comes to write the input code. Maybe this feature will be designed in,
> but it doesn’t sound like it is a very good 
feature to spend a bunch of time

> on. After all, the main problem is that the battery bank is just too darned
> small.
>
> Bob, Tom and Ryan do you have any comments on the subject?
>
> Thanks,
>
> Robin
>
>
>
> One idea I had in mind was to have an option, in software, to limit the
> current into the battery,
> when the charging current goes above some set threshold.  The controller
> would have to get its information from
> the battery monitor over the network.
>
> If it is a grid tie system and grid is there and GT inverter is selling,
> then no problem...  The controller
> can work at its full output.  If grid or loads go away, then the CC will
> know and it can throttle back at
> that time.
>
> We don't have a battery monitor yet, but we 
will have one.  This will be one

> of the settings as well as
> Re-Bulk based on state of charge, ending amps and those types of things.
>
> boB
>
> On 7/19/2012 8:34 PM, maver...@mavericksolar.com wrote:
>
> I say it is waste of time.
>
> 1. AGM batteries can take the high current and you are right, the absorb
> voltage is reached and the absorb current is 
tapered rather quickly. Current

> generation charge controllers are rather fast at the transitions. I have a
> bunch of data from a system with a PentaMetric that shows the battery bank
> going to absorb voltage at grid tie, during 
cloud events, but only for a few

> seconds at a time.
>
> 2. A properly designed GTBB system should cover the connected loads for 24
> hours of each sunny day, at a minimum. Keep in mind, off grid systems are
> designed for that, and 3 days + of backup, etc.
>
> 3. I would say, based on my experience, the minimum 

Re: [RE-wrenches] Array direct farm machinery?

[Steve McCarney]

Could the site use any refrigeration? There is a family of fridges called
"ice lined" and these store energy in the form of ice, avoiding the need
for a battery. Some are made for solar direct drive operation, but at lower
voltages (12-24 vdc nominal). They have reasonably long "autonomy" times at
constant hot temperatures (tested at either + 32C or +43C). Most will offer
5+ days of autonomy in those hot conditions.

Try Sundanzer (USA), True Energy (UK), Dometic (Luxemburg), Haier (China)
and Vestfrost (Denmark). All of these companies have these and all are
prequalified for vaccine storage by the WHO, however the companies would
let you know if they offer similar products to fit your needs. Sundanzer
also could supply a small freezer.

Steve McCarney, Project manager
Solar Electric Light Fund

On Thu, Jul 19, 2012 at 5:20 PM, Eric Youngren wrote:

> Howdy Wrenches,
>
> We are thinking up new ideas for powering agriculture in the rural
> developing world to propose for the new USAID "Energy Grand Challenge for
> Development" 
>
> One idea is to build PV array direct water pumping systems for irrigation
> that could be converted to power productive use farm machinery for grain
> milling, oil pressing or other farm processing jobs after the harvest is
> in.  The idea being that after the harvest they don't need the irrigation
> pumping for a bit and the PV array could be switched over to drive a motor
> to accomplish a mechanical task.  For that matter if it was an easy swap
> (Anderson 2 pole connectors, dual battery boat switches, etc) between the
> pumping load and the machinery load the same PV array could be used on any
> given day to either run the pump or the machine(s). I'd like to avoid
> batteries altogether and I'd like to allow a single 1 to 3 kW PV array to
> accomplish multiple array direct mechanical tasks.
>
> This is just a brainstorm at this point,  maybe this is a crazy idea and
> not worth pursuing, but I'd be really curious if anybody has any experience
> doing anything like this or any other ideas to bring to the table.
>
> Any ideas?  Thanks!
>
> Eric Youngren
> Solar Nexus International
> www.solarnexusinternational.com
>
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Re: [RE-wrenches] mounting hardware and U.L.

[Marco Mangelsdorf]

Thanks, Phil.

I just went to that website and do not know exactly what report you're
referring to.

Could you please provide the link?

marco


I don't think it's formally ratified, certified and adopted, but
UL2703 is the new proposed "Standard for Mounting Systems, Mounting
Devices, Clamping/Retention Devices, and Ground Lugs for Use with
Flat-Plate Photovoltaic Modules and Panels."  Also check out
SolarABCs.org for an update, there is a new report on this topic.

Phil

On Thu, Jul 19, 2012 at 4:12 PM, Jay Peltz  wrote:
> Is unistrut UL?
>
> Kay
>
> Peltz power
>
> Sent from my iPhone
>
> On Jul 19, 2012, at 6:36 PM, "Marco Mangelsdorf" 
> wrote:
>
> Does anyone know whether there are U.L. standards when it comes to PV
> mounting hardware?
>
>
>
> That is, are there any mounting hardware manufacturers (UniRac,
Professional
> Solar Products, DPW, Schletter) who have achieved U.L. listing/approval
for
> their stuff?
>
>
>
> After using PSP for the past 12 years here on the Big Island of Hawaii,
now,
> all of a sudden the new building division head is taking an interest as to
> whether PSP hardware is U.L. something or other.
>
>
>
> So very frustrating
>
>
>
> Thanks,
>
> marco
>
>
>
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Re: [RE-wrenches] mounting hardware and U.L.

[Dave Click]

http://solarabcs.org/about/publications/reports/module-grounding/index.html 
(see the Issues & Recommendations report)


Phil is right that UL 2703 isn't finalized yet so it's not actually a 
requirement. However, I imagine that module installation manuals and UL 
1703 will both refer to 2703 soon, so it's not something that you'll be 
able to ignore forever either. Since 2703 still isn't approved (see:
http://www.ul.com/global/eng/pages/solutions/standards/accessstandards/catalogofstandards/standard/?id=2703_1 
), I don't see how Unirac can claim that they have an ETL mark for 2703.


Ray is right that "an AHJ can't reasonably require equipment that 
doesn't exist." Just as NEC 2011 690.11 doesn't require you to use 
string inverters with arc fault protection, since no such unit is 
available (well, at least until SMA just started offering this for their 
standard low-freq Sunny Boys)-- no inspector should require anything 
listed to UL 2703 yet.


A relevant section is 90.4 (this section is copied from 2008).
**
The authority having jurisdiction for enforcement of the Code has the 
responsibility for making interpretations of the rules, for deciding on 
the approval of equipment and materials, and for granting the special 
permission contemplated in a number of the rules.


By special permission, the authority having jurisdiction may waive 
specific requirements in this Code or permit alternative methods where 
it is assured that equivalent objectives can be achieved by establishing 
and maintaining effective safety.


This Code may require new products, constructions, or materials that may 
not yet be available at the time the Code is adopted. In such event, the 
authority having jurisdiction may permit the use of the products, 
constructions, or materials that comply with the most recent previous 
edition of this Code adopted by the jurisdiction.

**


On 2012/7/20 0:52, Marco Mangelsdorf wrote:

Thanks, Phil.

I just went to that website and do not know exactly what report you're
referring to.

Could you please provide the link?

marco


I don't think it's formally ratified, certified and adopted, but
UL2703 is the new proposed "Standard for Mounting Systems, Mounting
Devices, Clamping/Retention Devices, and Ground Lugs for Use with
Flat-Plate Photovoltaic Modules and Panels."  Also check out
SolarABCs.org for an update, there is a new report on this topic.

Phil

On Thu, Jul 19, 2012 at 4:12 PM, Jay Peltz  wrote:

Is unistrut UL?

Kay

Peltz power

Sent from my iPhone

On Jul 19, 2012, at 6:36 PM, "Marco Mangelsdorf" 
wrote:

Does anyone know whether there are U.L. standards when it comes to PV
mounting hardware?



That is, are there any mounting hardware manufacturers (UniRac,

Professional

Solar Products, DPW, Schletter) who have achieved U.L. listing/approval

for

their stuff?



After using PSP for the past 12 years here on the Big Island of Hawaii,

now,

all of a sudden the new building division head is taking an interest as to
whether PSP hardware is U.L. something or other.



So very frustrating



Thanks,

marco



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Re: [RE-wrenches] Small battery bank vs too large array

[Brian Teitelbaum]

Phil,

Thanks for the very thorough explanation of the Global Charge Control. That 
setup would certainly provide the level of control that I was getting at.

I can see how the FN-DC could do that since it utilizes multiple shunts and can 
therefore use discrete amperage readings to provide better charge controlling 
functions. This will be very useful, not only for the type of system that you 
describe in Haiti, but for off-grid systems employing large PV arrays to 
provide adequate charging in foggy or overcast weather. With PV at a 
buck-a-Watt, this is starting to become a viable way to reduce battery size and 
cost without resorting to running a generator. PV lasts substantially longer 
than batteries, so is a better investment in my opinion

Brian Teitelbaum
AEE Solar



-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Phil 
Undercuffler
Sent: Thursday, July 19, 2012 9:35 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Small battery bank vs too large array

OutBack implemented Global Charge Control in the FM charge controllers a while 
back, based on the input of the good folk at SELF who worked to power a number 
of hospitals and clinics in Haiti after the earthquake.  In some of those 
systems, the PV array was based on the typical running consumption of the 
hospital, in the 30 - 100 kW if I remember right, and the battery bank was 
relatively modest. However, on the weekends and holidays without the normal AC 
loads the PV input was considerably more than the battery could absorb without 
destructive heating, something like a C2 or C5 rate.

Global Charge Control is implemented using the MATE3, a FN-DC and FM charge 
controllers set to GT mode.  You set a high charge current limit in the M3, and 
then it monitors the charge current going to the batteries.  In normal 
operating mode the controllers stay in wide open mode, harvesting as much power 
as possible.  However if the loads drop and the total current from the charging 
sources begin exceed the global charge limit, the system compensates and the 
controllers back off to prevent sending too much current to the batteries.

In today's world of PV modules being cheaper than diesel, we're seeing a lot 
more systems that can use this tool.

Hope this helps,

Phil



On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com  
wrote:
>
>
> I didn't see that Brian T had the same idea until after I sent that 
> email off to Allan...
> boB
>
>
>
>
>
> On 7/19/2012 7:53 PM, Allan Sindelar wrote:
>
> Wrenches,
> I forwarded Brian's post on to Robin at Midnite, as I thought it was 
> an interesting idea. Below is his response, as well as boB's.
> Allan
>
> Allan Sindelar
> al...@positiveenergysolar.com
> NABCEP Certified Photovoltaic Installer NABCEP Certified Technical 
> Sales Professional New Mexico EE98J Journeyman Electrician Founder and 
> Chief Technology Officer Positive Energy, Inc.
> 3209 Richards Lane (note new address)
> Santa Fe, New Mexico 87507
> 505 424-1112
> www.positiveenergysolar.com
>
> Allan, It is simpler than what is being suggested. The reason they 
> want to limit to 20 amps is because the battery doesn't need anymore 
> than that. The controller will automatically limit the charge current 
> as the battery gets full. If a large load is turned on, the controller 
> will try to refill the battery up to its capacity. The 80 amps will 
> quickly be reduced because the voltage will rise to the point where the 
> charge tapers off.
>
> There is nothing else that needs to be done. If the problem is that 
> the battery bank is too small for a big controller, the best answer is 
> to get more batteries. A 80 amp charger into a 200 amp hour battery is 
> going to raise the battery voltage so quick, it will not affect the battery 
> at all.
> By the way, discharging a battery at 60 or 80 amps is probably going 
> to do damage to a small battery also. We do have an input on the 
> Classic that could probably be programmed to do as requested. That 
> input feature has yet to be implemented. I'm sure we will have 
> discussions about this when the time comes to write the input code. 
> Maybe this feature will be designed in, but it doesn't sound like it 
> is a very good feature to spend a bunch of time on. After all, the 
> main problem is that the battery bank is just too darned small.
>
> Bob, Tom and Ryan do you have any comments on the subject?
>
> Thanks,
>
> Robin
>
>
>
> One idea I had in mind was to have an option, in software, to limit 
> the current into the battery, when the charging current goes above 
> some set threshold.  The controller would have to get its information 
> from the battery monitor over the network.
>
> If it is a grid tie system and grid is there and GT inverter is 
> selling, then no problem...  The controller can work at its full 
> output.  If grid or loads go away, then the CC will know and it can 
> throttle back at tha

[RE-wrenches] DC GEC Sizing Issue - Water Main GE

[Garrison Riegel]

Wrenches,

 

I have GEC sizing issue and would greatly appreciate any advice you can
share.

 

We have a small commercial grid-tie system installing on a facility with a
4000A, 240V, 3Ph service that uses the water main as the Ground Electrode.
My engineer is referencing NEC Table 250.66 (and the 4000A service entrance
cables) to size the GEC from the inverters to the GE, and therefore is
requiring a 3/0 (maximum size required by this table).

 

Since this is actually a DC GEC, I think it should be sized according to NEC
690.47(B) which references 250.166.  Since the GE is a water main it seems
that 250.166(B) would apply, requiring the GEC "shall not be smaller than
the largest conductor supplied by the system."  If taken literally, the
largest conductor supplied by the system could be the 4000A service entrance
cables, which would require a GEC even larger than the seemingly excessive
3/0.  For obvious reasons I hesitate to mention this to my engineer, but I
in the end I want to do what is best.

 

My questions:

 

1.Is my engineer correct, and we should size the GEC according to
250.66? 

 

2.If #1 is no, and 250.166(B) does apply, is "the largest conductor
supplied by this system" the 4000A service entrance cables, and the GEC size
should match these?

 

3.  Or, since 250.166 is written for DC systems, is this "largest
conductor" the DC source circuit conductors (#10 in this case), and
therefore the GEC can be a #8 (smallest size allowed)?

 

Thank you in advance,

 

Garrison 

 

Garrison Riegel

Project Manager 

 

Solar Service Inc

[p] 847-677-0950

www.solarserviceinc.com  

 

NABCEP Certified Solar PV and Thermal InstallerT

 

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Re: [RE-wrenches] High L16 voltage situation

[Nathan Jones]

Mystery solved. Morningstar vindicated. 
I had one of the guys go down on this so this is as I understand it. One of the 
2 solar panels was mis wired into the 12VDC lighting circuit. This panel was 
finding its way straight to the batteries through the load side of the charge 
controller. Apparently the Morningstar LVD clips on the high side as well as 
the low side of voltage. This simulated the current drop below my meters 
ability to read it yet still ran the voltage up to the 15.6VDC reading. I got 
tunnel vision to the controller thinking it was clipping current and 
functioning but at a wrong voltage. The AGM jumper also seems to control the 
LVD setpoints on the load portion of the controller which further put my focus 
on the controller as the culprit.
Mick got it right except the high voltage PWM cutout on the LVD took the 
runaway current out of the equation. I was seeing the problem but it was hidden 
in plain sight.
I hated to post that this thing kicked my butt. Morningstar deserved the clean 
bill of health. There is little of my face not covered by egg. That is only 
because I did not hook the thing up wrong to begin with. 
Thanks to all who offered help on this one.
Nathan Jones
Power Source Solar Inc.
417-827-0738
--
On Tue, Jul 17, 2012 4:58 PM CDT John DeBoever wrote:

>Nathan,
>
>
>
>Interesting controller situation...
>
>I recommend you contact Morningstar tech support center , (215) 321-4457 for 
>support. Ask for Adams.
>
>
>
>Hope they will clear this out.
>
>
>
>John
>
>
>John F. DeBoever
>Global Technical & Projects Director - Renewable Energy
>Trojan Battery Company
>
>12380 Clark Street
>Santa Fe Springs, CA 90670
>Tel: +1-562-236-3000 Ext. 3139
>Cell: +1-845-514-7600 - NY office time zone: USA EST (GMT-5)
>Skype: john.f.deboever
>Fax: +1-562-236-3239
>jdeboe...@trojanbattery.com
>www.trojanbattery.com
>
>
>
>
>
>
>
>
>
>-Original Message-
>From: re-wrenches-boun...@lists.re-wrenches.org 
>[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nathan Jones
>Sent: Tuesday, July 17, 2012 5:45 PM
>To: re-wrenches@lists.re-wrenches.org
>Subject: Re: [RE-wrenches] High L16 voltage situation
>
>
>
>
>
>
>
>
>
>John
>
>Two 12 volt nominal panels wired in parallel.
>
>Battery configuration is series/parallel at 12 volts nominal Controller (all 
>of them) have been 12 volt nominal PWM VPM is 17.7 VDC IPM is 7.91 Open 
>circuit voltage was down about 1 volt due to heat.
>
>I have not pulled the batteries down much below surface charge so max amperage 
>I have observed going back into the batteries has been 5 amps but it tapers 
>off within about 6 minutes as the controller regulates back to float. Absorb 
>and float are at 15.6VDC in all cases with all the controller combinations 
>unless I add the AGM jumper to the controller which does lower absorb and 
>float voltage to Morningstars published settings with the one controller I 
>attempted it with.
>
>Nathan Jones
>
>
>
>
>
>--
>
>On Tue, Jul 17, 2012 3:41 PM CDT John DeBoever wrote:
>
>
>
>>Nathan,
>
>>
>
>>
>
>>
>
>>Maybe the devil is in the details... Maybe the controller is confused and 
>>"sees" a 24V system... Just thinking...
>
>>
>
>>Kindly clarify few points:
>
>>
>
>>o   At which voltage the PV array is configured?  2x PV modules in parallel 
>>12V or  2x PV modules in series?
>
>>
>
>>o   Does the SunSaver Morningstar controller at the site is a 12V or a 24V 
>>version?
>
>>
>
>>o   What is the Vmp of the PV module?
>
>>
>
>>
>
>>
>
>>John
>
>>John F. DeBoever
>
>>Global Technical & Projects Director - Renewable Energy Trojan Battery
>
>>Company
>
>>
>
>>12380 Clark Street
>
>>Santa Fe Springs, CA 90670
>
>>Tel: +1-562-236-3000 Ext. 3139
>
>>Cell: +1-845-514-7600 - NY office time zone: USA EST (GMT-5)
>
>>Skype: john.f.deboever
>
>>Fax: +1-562-236-3239
>
>>jdeboe...@trojanbattery.com
>
>>www.trojanbattery.com
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>-Original Message-
>
>>From: re-wrenches-boun...@lists.re-wrenches.org
>
>>[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nathan
>
>>Jones
>
>>Sent: Tuesday, July 17, 2012 4:36 PM
>
>>To: re-wrenches@lists.re-wrenches.org
>
>>Subject: Re: [RE-wrenches] High L16 voltage situation
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>
>
>>Mick,
>
>>
>
>>Pesky is a nicer term than I had been using. I clamped the charge circuit and 
>>watched the amperage come in on final phase of absorb then drop to zero. 
>>(Since the voltage stayed at the same 15.6VDC when the amperage dropped off 
>>there was some current but my meter could not read it. That is the pesky 
>>part. Everything seems to be behaving as it should be. I will try the 
>>splitting of the parall

Re: [RE-wrenches] DC GEC Sizing Issue - Water Main GE

[Dave Click]

Garrison,

If you're doing a small commercial grid-tie system, your inverter GEC 
requirements are determined not by the service size but by your 
inverter. To illustrate, if you were installing a single Enphase, 
running an unspliced #3/0 copper wire from your pipe up to your inverter 
would be overkill, right? 690.47(B) is for systems with DC requirements 
only (e.g. small inverter-free stand-alone systems).


If you're on the 2011 NEC, the simplest way to do this is to run a 
combination EGC/GEC from the inverter GEC terminal *unspliced* through 
your AC conduit to the ground bus of your interconnection panelboard, 
sizing it to meet DC GEC and AC EGC requirements. If you're on the 2008 
and your inspector won't allow you to use the 2011 method, you'd run and 
size your AC EGC as you normally would. For your GEC you would size that 
based off the larger of 250.66 or 250.166, and note that 250.166(B) 
doesn't apply since you have a pipe electrode (250.166(C) overrides 
166(B)). So you can get away with a #6 copper GEC unspliced from your 
inverter to your pipe. Run that GEC in PVC conduit if you can, but if 
the site requires you to use metal, you'll need to bond both ends.


To answer your questions:
1. Per 2008, you'll size the GEC per 250.66 and 250.166, and the .166 
requirement will likely win out. Per 2011, you'll size your combined 
EGC/GEC as no smaller than 250.122 or 250.166.


2 & 3. "Largest conductor" applies to the largest conductor in the PV 
system (likely your homerun DC).


Dave

On 2012/7/20 15:06, Garrison Riegel wrote:

Wrenches,

I have GEC sizing issue and would greatly appreciate any advice you can
share.

We have a small commercial grid-tie system installing on a facility with
a 4000A, 240V, 3Ph service that uses the water main as the Ground
Electrode.  My engineer is referencing NEC Table 250.66 (and the 4000A
service entrance cables) to size the GEC from the inverters to the GE,
and therefore is requiring a 3/0 (maximum size required by this table).

Since this is actually a DC GEC, I think it should be sized according to
NEC 690.47(B) which references 250.166.  Since the GE is a water main it
seems that 250.166(B) would apply, requiring the GEC “/shall not be
smaller than the largest conductor supplied by the system.” /If taken
literally, the largest conductor supplied by the system could be the
4000A service entrance cables, which would require a GEC even larger
than the seemingly excessive 3/0.  For obvious reasons I hesitate to
mention this to my engineer, but I in the end I want to do what is best.

//

My questions:

//

1.Is my engineer correct, and we should size the GEC according to
250.66?

2.If #1 is no, and 250.166(B) does apply, is “the largest conductor
supplied by this system” the 4000A service entrance cables, and the GEC
size should match these?

 3. Or, since 250.166 is written for DC systems, is this “largest
conductor” the DC source circuit conductors (#10 in this case), and
therefore the GEC can be a #8 (smallest size allowed)?

Thank you in advance,

Garrison

Garrison Riegel

Project Manager

*Solar Service Inc*

[p] 847-677-0950

www.solarserviceinc.com 

NABCEP Certified Solar PV and Thermal Installer™



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Re: [RE-wrenches] Small battery bank vs too large array

[Chris Mason]

Phil,
Good explanation of the feature. When did GCC make it into the firmware,
and can the older ones be updated? It sounds like a perfect solution for
some of my installations.

On Fri, Jul 20, 2012 at 12:34 AM, Phil Undercuffler wrote:

> OutBack implemented Global Charge Control in the FM charge controllers
> a while back, based on the input of the good folk at SELF who worked
> to power a number of hospitals and clinics in Haiti after the
> earthquake.  In some of those systems, the PV array was based on the
> typical running consumption of the hospital, in the 30 - 100 kW if I
> remember right, and the battery bank was relatively modest. However,
> on the weekends and holidays without the normal AC loads the PV input
> was considerably more than the battery could absorb without
> destructive heating, something like a C2 or C5 rate.
>
> Global Charge Control is implemented using the MATE3, a FN-DC and FM
> charge controllers set to GT mode.  You set a high charge current
> limit in the M3, and then it monitors the charge current going to the
> batteries.  In normal operating mode the controllers stay in wide open
> mode, harvesting as much power as possible.  However if the loads drop
> and the total current from the charging sources begin exceed the
> global charge limit, the system compensates and the controllers back
> off to prevent sending too much current to the batteries.
>
> In today's world of PV modules being cheaper than diesel, we're seeing
> a lot more systems that can use this tool.
>
> Hope this helps,
>
> Phil
>
>
>
> On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com
>  wrote:
> >
> >
> > I didn't see that Brian T had the same idea until after I sent that email
> > off to Allan...
> > boB
> >
> >
> >
> >
> >
> > On 7/19/2012 7:53 PM, Allan Sindelar wrote:
> >
> > Wrenches,
> > I forwarded Brian's post on to Robin at Midnite, as I thought it was an
> > interesting idea. Below is his response, as well as boB's.
> > Allan
> >
> > Allan Sindelar
> > al...@positiveenergysolar.com
> > NABCEP Certified Photovoltaic Installer
> > NABCEP Certified Technical Sales Professional
> > New Mexico EE98J Journeyman Electrician
> > Founder and Chief Technology Officer
> > Positive Energy, Inc.
> > 3209 Richards Lane (note new address)
> > Santa Fe, New Mexico 87507
> > 505 424-1112
> > www.positiveenergysolar.com
> >
> > Allan, It is simpler than what is being suggested. The reason they want
> to
> > limit to 20 amps is because the battery doesn’t need anymore than that.
> The
> > controller will automatically limit the charge current as the battery
> gets
> > full. If a large load is turned on, the controller will try to refill the
> > battery up to its capacity. The 80 amps will quickly be reduced because
> the
> > voltage will rise to the point where the charge tapers off.
> >
> > There is nothing else that needs to be done. If the problem is that the
> > battery bank is too small for a big controller, the best answer is to get
> > more batteries. A 80 amp charger into a 200 amp hour battery is going to
> > raise the battery voltage so quick, it will not affect the battery at
> all.
> > By the way, discharging a battery at 60 or 80 amps is probably going to
> do
> > damage to a small battery also. We do have an input on the Classic that
> > could probably be programmed to do as requested. That input feature has
> yet
> > to be implemented. I’m sure we will have discussions about this when the
> > time comes to write the input code. Maybe this feature will be designed
> in,
> > but it doesn’t sound like it is a very good feature to spend a bunch of
> time
> > on. After all, the main problem is that the battery bank is just too
> darned
> > small.
> >
> > Bob, Tom and Ryan do you have any comments on the subject?
> >
> > Thanks,
> >
> > Robin
> >
> >
> >
> > One idea I had in mind was to have an option, in software, to limit the
> > current into the battery,
> > when the charging current goes above some set threshold.  The controller
> > would have to get its information from
> > the battery monitor over the network.
> >
> > If it is a grid tie system and grid is there and GT inverter is selling,
> > then no problem...  The controller
> > can work at its full output.  If grid or loads go away, then the CC will
> > know and it can throttle back at
> > that time.
> >
> > We don't have a battery monitor yet, but we will have one.  This will be
> one
> > of the settings as well as
> > Re-Bulk based on state of charge, ending amps and those types of things.
> >
> > boB
> >
> > On 7/19/2012 8:34 PM, maver...@mavericksolar.com wrote:
> >
> > I say it is waste of time.
> >
> > 1. AGM batteries can take the high current and you are right, the absorb
> > voltage is reached and the absorb current is tapered rather quickly.
> Current
> > generation charge controllers are rather fast at the transitions. I have
> a
> > bunch of data from a system with a PentaMetric that shows the battery
> bank
> > going to abso

Re: [RE-wrenches] Small battery bank vs too large array

[Phil Undercuffler]

Hi all, I just got a correction from Darren - global charge control is in
the Mate3, and therefore works with any FM or MX controller that has the GT
mode. It uses the current sense from the FN-DC and the GT mode signal to
control the output of the controllers.

Sorry for any confusion

Phil
On Jul 20, 2012 4:11 PM, "Chris Mason"  wrote:

> Phil,
> Good explanation of the feature. When did GCC make it into the firmware,
> and can the older ones be updated? It sounds like a perfect solution for
> some of my installations.
>
> On Fri, Jul 20, 2012 at 12:34 AM, Phil Undercuffler 
> wrote:
>
>> OutBack implemented Global Charge Control in the FM charge controllers
>> a while back, based on the input of the good folk at SELF who worked
>> to power a number of hospitals and clinics in Haiti after the
>> earthquake.  In some of those systems, the PV array was based on the
>> typical running consumption of the hospital, in the 30 - 100 kW if I
>> remember right, and the battery bank was relatively modest. However,
>> on the weekends and holidays without the normal AC loads the PV input
>> was considerably more than the battery could absorb without
>> destructive heating, something like a C2 or C5 rate.
>>
>> Global Charge Control is implemented using the MATE3, a FN-DC and FM
>> charge controllers set to GT mode.  You set a high charge current
>> limit in the M3, and then it monitors the charge current going to the
>> batteries.  In normal operating mode the controllers stay in wide open
>> mode, harvesting as much power as possible.  However if the loads drop
>> and the total current from the charging sources begin exceed the
>> global charge limit, the system compensates and the controllers back
>> off to prevent sending too much current to the batteries.
>>
>> In today's world of PV modules being cheaper than diesel, we're seeing
>> a lot more systems that can use this tool.
>>
>> Hope this helps,
>>
>> Phil
>>
>>
>>
>> On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com
>>  wrote:
>> >
>> >
>> > I didn't see that Brian T had the same idea until after I sent that
>> email
>> > off to Allan...
>> > boB
>> >
>> >
>> >
>> >
>> >
>> > On 7/19/2012 7:53 PM, Allan Sindelar wrote:
>> >
>> > Wrenches,
>> > I forwarded Brian's post on to Robin at Midnite, as I thought it was an
>> > interesting idea. Below is his response, as well as boB's.
>> > Allan
>> >
>> > Allan Sindelar
>> > al...@positiveenergysolar.com
>> > NABCEP Certified Photovoltaic Installer
>> > NABCEP Certified Technical Sales Professional
>> > New Mexico EE98J Journeyman Electrician
>> > Founder and Chief Technology Officer
>> > Positive Energy, Inc.
>> > 3209 Richards Lane (note new address)
>> > Santa Fe, New Mexico 87507
>> > 505 424-1112
>> > www.positiveenergysolar.com
>> >
>> > Allan, It is simpler than what is being suggested. The reason they want
>> to
>> > limit to 20 amps is because the battery doesn’t need anymore than that.
>> The
>> > controller will automatically limit the charge current as the battery
>> gets
>> > full. If a large load is turned on, the controller will try to refill
>> the
>> > battery up to its capacity. The 80 amps will quickly be reduced because
>> the
>> > voltage will rise to the point where the charge tapers off.
>> >
>> > There is nothing else that needs to be done. If the problem is that the
>> > battery bank is too small for a big controller, the best answer is to
>> get
>> > more batteries. A 80 amp charger into a 200 amp hour battery is going to
>> > raise the battery voltage so quick, it will not affect the battery at
>> all.
>> > By the way, discharging a battery at 60 or 80 amps is probably going to
>> do
>> > damage to a small battery also. We do have an input on the Classic that
>> > could probably be programmed to do as requested. That input feature has
>> yet
>> > to be implemented. I’m sure we will have discussions about this when the
>> > time comes to write the input code. Maybe this feature will be designed
>> in,
>> > but it doesn’t sound like it is a very good feature to spend a bunch of
>> time
>> > on. After all, the main problem is that the battery bank is just too
>> darned
>> > small.
>> >
>> > Bob, Tom and Ryan do you have any comments on the subject?
>> >
>> > Thanks,
>> >
>> > Robin
>> >
>> >
>> >
>> > One idea I had in mind was to have an option, in software, to limit the
>> > current into the battery,
>> > when the charging current goes above some set threshold.  The controller
>> > would have to get its information from
>> > the battery monitor over the network.
>> >
>> > If it is a grid tie system and grid is there and GT inverter is selling,
>> > then no problem...  The controller
>> > can work at its full output.  If grid or loads go away, then the CC will
>> > know and it can throttle back at
>> > that time.
>> >
>> > We don't have a battery monitor yet, but we will have one.  This will
>> be one
>> > of the settings as well as
>> > Re-Bulk based on state of charge, ending amps and

Re: [RE-wrenches] Small battery bank vs too large array

[Chris Mason]

Is there a document available on how this world?

On Friday, July 20, 2012, Phil Undercuffler  wrote:
> Hi all, I just got a correction from Darren - global charge control is in
the Mate3, and therefore works with any FM or MX controller that has the GT
mode. It uses the current sense from the FN-DC and the GT mode signal to
control the output of the controllers.
>
> Sorry for any confusion
>
> Phil
>
> On Jul 20, 2012 4:11 PM, "Chris Mason" 
wrote:
>
> Phil,
> Good explanation of the feature. When did GCC make it into the firmware,
and can the older ones be updated? It sounds like a perfect solution for
some of my installations.
>
> On Fri, Jul 20, 2012 at 12:34 AM, Phil Undercuffler 
wrote:
>
> OutBack implemented Global Charge Control in the FM charge controllers
> a while back, based on the input of the good folk at SELF who worked
> to power a number of hospitals and clinics in Haiti after the
> earthquake.  In some of those systems, the PV array was based on the
> typical running consumption of the hospital, in the 30 - 100 kW if I
> remember right, and the battery bank was relatively modest. However,
> on the weekends and holidays without the normal AC loads the PV input
> was considerably more than the battery could absorb without
> destructive heating, something like a C2 or C5 rate.
>
> Global Charge Control is implemented using the MATE3, a FN-DC and FM
> charge controllers set to GT mode.  You set a high charge current
> limit in the M3, and then it monitors the charge current going to the
> batteries.  In normal operating mode the controllers stay in wide open
> mode, harvesting as much power as possible.  However if the loads drop
> and the total current from the charging sources begin exceed the
> global charge limit, the system compensates and the controllers back
> off to prevent sending too much current to the batteries.
>
> In today's world of PV modules being cheaper than diesel, we're seeing
> a lot more systems that can use this tool.
>
> Hope this helps,
>
> Phil
>
>
>
> On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com
>  wrote:
>>
>>
>> I didn't see that Brian T had the same idea until after I sent that email
>> off to Allan...
>> boB
>>
>>
>>
>>
>>
>> On 7/19/2012 7:53 PM, Allan Sindelar wrote:
>>
>> Wrenches,
>> I forwarded Brian's post on to Robin at Midnite, as I thought it was an
>> interesting idea. Below is his response, as well as boB's.
>> Allan
>>
>> Allan Sindelar
>> al...@positiveenergysolar.com
>> NABCEP Certified Photovoltaic Installer
>> NABCEP Certified Technical Sales Professional
>> New Mexico EE98J Journeyman Electrician
>> Founder and Chief Technology Officer
>> Positive Energy, Inc.
>> 3209 Richards Lane (note new address)
>> Santa Fe, New Mexico 87507
>> 505 424-1112
>> www.positiveenergysolar.com
>>
>> Allan, It is simpler than what is being suggested. The reason they want
to
>> limit to 20 amps is because the battery doesn’t need anymore than that.
The
>> controller will automatically limit the charge current as the battery
gets
>> full. If a large load is turned on, the controller will try to refill the
>> battery up to its capacity. The 80 amps will quickly be reduced because
the
>> voltage will rise to the point where the charge tapers off.
>>
>> There is nothing else that needs to be done. If the problem is that the
>> battery bank is too small for a big controller, the best answer is to get
>> more batteries. A 80 amp charger into a 200 amp hour battery is going to
>> raise the battery voltage so quick, it will not affect the battery at
all.
>> By the way, discharging a battery at 60 or 80 amps is probably going to
do
>> damage to a small battery also. We do have an input on the Classic that
>> could probably be programmed to do as requested. That input feature has
yet
>> to be implemented. I’m sure we will have discussions about this when the
>> time comes to write the input code. Maybe this feature will be designed
in,
>> but it doesn’t sound like it is a very good feature to spend a bunch of
time
>> on. After all, the main problem is that the battery bank is just too
darned<

-- 
Chris Mason
President, Comet Systems Ltd
www.cometenergysystems.com
Cell: 264.235.5670
Skype: netconcepts
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Re: [RE-wrenches] Small battery bank vs too large array

[Philip]

Page 127 of the Mate3 manual.

Phil




On Jul 20, 2012, at 7:49 PM, Chris Mason  wrote:

> Is there a document available on how this world?
> 
> On Friday, July 20, 2012, Phil Undercuffler  wrote:
> > Hi all, I just got a correction from Darren - global charge control is in 
> > the Mate3, and therefore works with any FM or MX controller that has the GT 
> > mode. It uses the current sense from the FN-DC and the GT mode signal to 
> > control the output of the controllers.
> >
> > Sorry for any confusion
> >
> > Phil
> >
> > On Jul 20, 2012 4:11 PM, "Chris Mason"  wrote:
> >
> > Phil,
> > Good explanation of the feature. When did GCC make it into the firmware, 
> > and can the older ones be updated? It sounds like a perfect solution for 
> > some of my installations.
> >
> > On Fri, Jul 20, 2012 at 12:34 AM, Phil Undercuffler  
> > wrote:
> >
> > OutBack implemented Global Charge Control in the FM charge controllers
> > a while back, based on the input of the good folk at SELF who worked
> > to power a number of hospitals and clinics in Haiti after the
> > earthquake.  In some of those systems, the PV array was based on the
> > typical running consumption of the hospital, in the 30 - 100 kW if I
> > remember right, and the battery bank was relatively modest. However,
> > on the weekends and holidays without the normal AC loads the PV input
> > was considerably more than the battery could absorb without
> > destructive heating, something like a C2 or C5 rate.
> >
> > Global Charge Control is implemented using the MATE3, a FN-DC and FM
> > charge controllers set to GT mode.  You set a high charge current
> > limit in the M3, and then it monitors the charge current going to the
> > batteries.  In normal operating mode the controllers stay in wide open
> > mode, harvesting as much power as possible.  However if the loads drop
> > and the total current from the charging sources begin exceed the
> > global charge limit, the system compensates and the controllers back
> > off to prevent sending too much current to the batteries.
> >
> > In today's world of PV modules being cheaper than diesel, we're seeing
> > a lot more systems that can use this tool.
> >
> > Hope this helps,
> >
> > Phil
> >
> >
> >
> > On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com
> >  wrote:
> >>
> >>
> >> I didn't see that Brian T had the same idea until after I sent that email
> >> off to Allan...
> >> boB
> >>
> >>
> >>
> >>
> >>
> >> On 7/19/2012 7:53 PM, Allan Sindelar wrote:
> >>
> >> Wrenches,
> >> I forwarded Brian's post on to Robin at Midnite, as I thought it was an
> >> interesting idea. Below is his response, as well as boB's.
> >> Allan
> >>
> >> Allan Sindelar
> >> al...@positiveenergysolar.com
> >> NABCEP Certified Photovoltaic Installer
> >> NABCEP Certified Technical Sales Professional
> >> New Mexico EE98J Journeyman Electrician
> >> Founder and Chief Technology Officer
> >> Positive Energy, Inc.
> >> 3209 Richards Lane (note new address)
> >> Santa Fe, New Mexico 87507
> >> 505 424-1112
> >> www.positiveenergysolar.com
> >>
> >> Allan, It is simpler than what is being suggested. The reason they want to
> >> limit to 20 amps is because the battery doesn’t need anymore than that. The
> >> controller will automatically limit the charge current as the battery gets
> >> full. If a large load is turned on, the controller will try to refill the
> >> battery up to its capacity. The 80 amps will quickly be reduced because the
> >> voltage will rise to the point where the charge tapers off.
> >>
> >> There is nothing else that needs to be done. If the problem is that the
> >> battery bank is too small for a big controller, the best answer is to get
> >> more batteries. A 80 amp charger into a 200 amp hour battery is going to
> >> raise the battery voltage so quick, it will not affect the battery at all.
> >> By the way, discharging a battery at 60 or 80 amps is probably going to do
> >> damage to a small battery also. We do have an input on the Classic that
> >> could probably be programmed to do as requested. That input feature has yet
> >> to be implemented. I’m sure we will have discussions about this when the
> >> time comes to write the input code. Maybe this feature will be designed in,
> >> but it doesn’t sound like it is a very good feature to spend a bunch of 
> >> time
> >> on. After all, the main problem is that the battery bank is just too 
> >> darned<
> 
> -- 
> Chris Mason
> President, Comet Systems Ltd
> www.cometenergysystems.com
> Cell: 264.235.5670
> Skype: netconcepts
> 
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