EV Digest 5576
Topics covered in this issue include:
1) RE: Odd lee reg issue on charging
by "Roger Stockton" <[EMAIL PROTECTED]>
2) Gazelle (1929 Mercedes replica) kitcar FREE - conversion candidat
e on Craigslist
by Cor van de Water <[EMAIL PROTECTED]>
3) Re: Add on Regenerative Braking
by "Michaela Merz" <[EMAIL PROTECTED]>
4) Re: Simultaneous Contactor-gasm
by Lee Hart <[EMAIL PROTECTED]>
5) Re: Motor / differential question...
by [EMAIL PROTECTED]
6) Re: Motor / differential question...
by "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
7) RE: Maybe OT: EVDL withdrawl - strange problem with EVDL
by "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
8) Re: Odd lee reg issue on charging
by Christopher Zach <[EMAIL PROTECTED]>
9) RE: Circuit breaker question
by "Roger Stockton" <[EMAIL PROTECTED]>
10) Re: Add on Regenerative Braking
by [EMAIL PROTECTED]
11) Re: Current Eliminator News!!!!!!
by [EMAIL PROTECTED]
12) RE: Odd lee reg issue on charging
by "Roger Stockton" <[EMAIL PROTECTED]>
13) RE: Odd lee reg issue on charging
by "Tim Humphrey" <[EMAIL PROTECTED]>
14) Re: 36v li-ion batteries on sale
by "Philippe Borges" <[EMAIL PROTECTED]>
15) RE: Anyone Use Brake by Wire and Regen
by "Jonathan Smith" <[EMAIL PROTECTED]>
16) Regen Off the Bat
by "Bill Dennis" <[EMAIL PROTECTED]>
17) Re: one for the Sinclair C5 owners...
by Lee Hart <[EMAIL PROTECTED]>
18) AC low power inverter kit
by Kaido Kert <[EMAIL PROTECTED]>
19) rev limiters
by [EMAIL PROTECTED]
20) RE: rev limiters
by "Roger Stockton" <[EMAIL PROTECTED]>
21) Re: Motor / differential question...
by Lee Hart <[EMAIL PROTECTED]>
22) Re: Add on Regenerative Braking
by Mike Chancey <[EMAIL PROTECTED]>
--- Begin Message ---
Christopher Zach wrote:
> Ok, strange question here with the zener regs and a charging profile.
> I have been using a Magnecharger profile of:
>
> Charge 12a rate to 340 volts
> Hold 340 volts till charge rate drops to 2a
> Charge at 2a to 365 volts
>
> With temp compensation based on a 30 degree base pack temp.
What is the temp compensation factor (V/cell/degree C/F)?
> Anyway, what happened last night was after the MC kicked off
> I decided to try the Dolphin charger to see if it would take
> the batteries to 390v. Dolphin charger is a 2a constant
> current. So I plugged in, came back in an hour. +2ah on the
> e-meter, 350 volts. Came back in 2 hours, +4ah on the e-meter,
> still 350 volts.
>
> Odd. I unplugged and went to bed. This morning I plugged in
> (pack and everything was cool by then) and came back in 30
> mins. Pack was at a nice 390 volts, charge complete.
You've stated the answer: pack was nice and cool and behaved as
expected. Right after charging with the MC, it was hot, and so while
you couldn't get thermal runaway with the constant current Dolphin, you
also couldn't get the batteries up to the voltage you expected.
Does the Dolphin blindly run 2A until some timeout, or does it shut off
when it reaches the target voltage (390V)? Is it temp compensated?
I'm going to assume that it shuts off when it hits 390V, but is not temp
compensated, so it did not adjust its voltage target downwards
appropriately for the hot pack.
> Does this strike anyone as odd. This evening after a 20a run,
> I plugged into the MC and let it run. It was still gong at
> 11:30pm tonight, and a check of the software showed me that
> although the pack was at 339 volts, the MC thought it was at
> 360 due to the temp compensation. Checking temps showed that
> the battery interconnects (and the heat sinks for the diodes,
> two diodes per interconnect) were at anywhere from 43 to 50
> degrees C.
Aren't your battery temperatures also measured at the interconnects?
The issue you appear to be having is that the clampers are dumping their
waste heat into the battery temp sensors (or conversely, you are sensing
clamper heatsink temp, not necessarily battery temp).
Given the behaviour of the pack with the Dolphin, it seems that the
batteries really are getting hot, so while the interconnect temp may not
accurately reflect the battery temp, the heat being dumped into the
interconnects is making it into the batteries.
I would expect that the largest issue you have is that the new heat from
the clampers is being dumped inside the battery boxes, and is heating up
the batteries.
I would suggest that if you can't get the clampers out of the boxes, you
may want to try charging in 2 phases, shutting off the MC (if you can't
program it to insert a rest phase) after it hits the 340V threshold, and
allowing the batteries at least a few hours to cool a bit before
resuming the MC so it can complete.
With the Dolphin you may have greater issues. Due to its low current
nature, it may tend to keep the clampers active longer (at the lower
charge rate, the pack voltage will rise more slowly and so will spend
longer in the range where the clampers are active before the batteries
reach full and the termination criteria are met), which will allow more
time for the heat from the clampers to 'soak' into the batteries and
affect their behaviour.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Apparently must go today, see text of ad below.
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
http://www.craigslist.org/eby/zip/173126538.html
Free Kitcar - Gazelle - (dublin / pleasanton / livermore)
----------------------------------------------------------------------------
----
Reply to: [EMAIL PROTECTED]
Date: 2006-06-19, 10:22AM PDT
No Engine - No trans - no interior REAL ROUGH condition - BASICALLY A Body
on a frame - Had the Pinto 4 banger in it . Front engine setup. If you have
to ask what a Gazelle is don't reply. Must be taken today !!!! Rolls and
steers but parking brake not hooked up.
--- End Message ---
--- Begin Message ---
Mike, wow, this would be it. That is more or less exactly what I had in
mind when I made my suggestions some time ago. I would need a 144V
version, but that's just a detail.
Well, if anybody considers to built such a unit, put me on file for the
first unit ;)
Michaela
Mike wrote:
> Hi folks,
>
> A while back we were discussing things we wish we could get for EV
> conversions, and I mentioned the regen setup that Solar Car Corp
> offered. I found a flyer on it they had sent me years ago, scanned
> it, and posted on the web at:
>
> http://www.austinev.org/evalbum/tech/regen.jpg
>
> Please keep in mind these folks went out of business years ago, so
> don't try to contact them.
>
> Anyway, It looks to me that aside from the brackets and having the
> alternator rewound, most of it looks like off the shelf
> stuff. Surely this is something that would sell well enough to
> justify making them again.
>
> So, anyone know how we could get this into production?
>
> Thanks,
>
> Mike Chancey,
> '88 Civic EV
> Kansas City, Missouri
> EV Photo Album at: http://evalbum.com
> My Electric Car at: http://www.geocities.com/electric_honda
> Mid-America EAA chapter at: http://maeaa.org
> Join the EV List at: http://www.madkatz.com/ev/evlist.html
>
> In medio stat virtus - Virtue is in the moderate, not the extreme
> position. (Horace)
>
--- End Message ---
--- Begin Message ---
Bill Dennis wrote:
> Lee... thinking that maybe what I'm planning with my contactors
> might cause problems...
>
> - two contactors, one on each side of controller
> - keyswitch causes negative side contactor to close
> - manually switch pre-charge resistor across positive contactor
> - pre-charge resistor stays closed during driving
>
> My plan has been to leave the negative contactor closed the whole
> time while driving, too, and open and close the positive contactor
> only.
I assume the positive contactor opens when you release the gas pedal, by
opening the potbox microswitch. That's fine under normal driving
conditions. The contactor is switching essentially zero volts and amps,
and so lasts forever.
> - when the keyswitch is turned off, both the negative contactor and
> the precharge resistor open.
The key point is what happens when a fault occurs (such as the
controller sticking full-on). Your first reation would be to release the
gas pedal; that turns off the positive contactor. In this case, it alone
has to break full pack voltage and full current. So, it has to be rated
to handle full pack voltage, and whatever short circuit current you
batteries can dish out.
If it isn't rated that high, then you need some sort of protection
circuit that makes BOTH contactors drop if a fault occurs. Then each
contactor can be rated for half the pack voltage (but still must be able
to break the worst-case fault current).
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
>Which components on a vehicle are 'unsprung'?
That is everything that is attached to the wheels. As the wheels hit bumps,
the springs allow the wheels to follow the bump but not the car. Since the
differential is attached directly to the wheels it has to follow the bump
impacts just as the wheels do. (unless it has independent suspension).
>How does a normal drive-train (driveshaft, transmission, etc.) help the rear
>axle handle the shearing forces of potholes?
>Is it all in those thingies they call 'u-joints'?
The rear axle is a very tough part and has to handle the pothole forces. The
U-Joints decouple the axle from everything else so everything else does not get
the impact forces. Mounting the motor to the differential means a heavy weight
is added on an off axis angle making the shear forces exaggerated at the mount.
I suspect it would also subject the motor to more mechanical shock than
desired.
I was considering a ladder bar type suspension where the motor was as close to
the forward pivot point of the ladder as possible. That would reduce the
motion and shock to the motor and would eliminate the spring twist problem.
Thanks everyone for your comments! Please keep them coming.
Ken
-----Original Message-----
From: Meta Bus <[EMAIL PROTECTED]>
To: [email protected]
Sent: Mon, 19 Jun 2006 13:23:13 -0400
Subject: Re: Motor / differential question...
Cor van de Water wrote:
> The rear axle will try to shed the motor with every bump in the road,
Mr Roden mentioned 'unsprung weight' too...
As a software guy, I am still learning the stuff that arises when you actually
get your hands dirty :-), (I didn't take auto shop), so forgive my ignorance
and what are probably very basic questions--
Which components on a vehicle are 'unsprung'?
How does a normal drive-train (driveshaft, transmission, etc.) help the rear
axle handle the shearing forces of potholes?
Is it all in those thingies they call 'u-joints'?
Tanks.
> as it is loaded to one side of the axle (assuming you have a solid
> axle, no half-shafts) so every up/down movement of the axle
> creates a torque on the rear axle.
> Since a pothole (or other fast transition) creates a high speed
> change of axle position, the torque will be pretty large on the
> rear axle and motor mount.
> You will have to design for those forces and the handling of the
> car will change accordingly with all the added unsprung weight.
> Also check the axle attachment - how will it offload the torque?
> Spring leaves will be extra twisted...
> > Regards,
> > Cor van de Water
> Systems Architect
> Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
> Skype: cor_van_de_water IM: [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Proxim Wireless Networks eFAX: +1-610-423-5743
> Take your network further http://www.proxim.com
> > > -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of [EMAIL PROTECTED]
> Sent: Monday, June 19, 2006 6:52 AM
> To: [email protected]
> Subject: Motor / differential question...
> > > I am considering mounting a motor directly to a differential. that is, no
> drive shaft, just mount the motor to the front of the differential housing.
> Remove the yoke and fabricate a coupling to the motor and an adapter to bolt
> the motor to the differential housing. Maybe keep the yoke to simplify
> preload but couple the motor directly to the yoke - no drive shaft.
> Any comments on this idea?
> > Ken
> > > ________________________________________________________________________
> Check out AOL.com today. Breaking news, video search, pictures, email and
> IM. All on demand. Always Free.
> >
________________________________________________________________________
Check out AOL.com today. Breaking news, video search, pictures, email and IM.
All on demand. Always Free.
--- End Message ---
--- Begin Message ---
On 19 Jun 2006 at 13:23, Meta Bus wrote:
> Which components on a vehicle are 'unsprung'?
Unsprung weight refers to mass which is not isolated from the road by the
suspension - that is, mass which follows the road instead of the vehicle body.
This includes the wheels, brake assembly, and in many cases a rear axle of
some kind.
>
> How does a normal drive-train (driveshaft, transmission, etc.) help the
> rear axle handle the shearing forces of potholes?
There's usually some play or lash in the driveline. What you want is some
resilient component. One good reason to retain the clutch in a conversion is
that the springs in the clutch disc are effective at dissipating road shock.
David Roden
EV List Assistant Administrator
--- End Message ---
--- Begin Message ---
On 19 Jun 2006 at 9:00, Cor van de Water wrote:
> Blacklisted by a spam killer?
We really don't know what the problem was. It appears that email sent in
both directions was failing in transit somewhere about 80% of the time, with
no bounces or error messages returned. The cause seems to have resolved
spontaneously, or more likely was corrected when another locally-diagnosed
problem was fixed.
When in doubt, blame AT&T. (Just kidding.)
David Roden
EV List Assistant Administrator
--- End Message ---
--- Begin Message ---
Roger Stockton wrote:
What is the temp compensation factor (V/cell/degree C/F)?
Something like .1mv per cell per degree C, always compensate based on
the highest temp sensor in the pack. With a count of 150 cells per
string, it adds up.
You've stated the answer: pack was nice and cool and behaved as
expected. Right after charging with the MC, it was hot, and so while
you couldn't get thermal runaway with the constant current Dolphin, you
also couldn't get the batteries up to the voltage you expected.
Well, could I get thermal runaway on some cells? Can a battery that is
being held at a max of 14.7 still run away if it gets hot?
I should read up on exactly what thermal runaway is. With clampers on
top of the battery putting heat into the battery it might be getting a
bit more complex than normal.
Does the Dolphin blindly run 2A until some timeout, or does it shut off
when it reaches the target voltage (390V)? Is it temp compensated?
Yes. The Dolphin is pretty stupid. I only use it every once in a while
to make sure things are topping up.
Now that I don't need to go to 390 ever again (thank you clampers :-) I
intend to change the top value down to something like 367.5 or so.
However my record of completely screwing up Dolphin 68HC711 chips is now
two in a row. The problem is though you can program EEPROM through the
DOL7 program, it won't let you change it if the chip is in fault state.
Thus it's easy to make a mistake and wind up with a chip that will not
allow the Dolphin to get to ready. Think chicken, egg.
My solution on this BTW is to spend $10 at Mouser, $60 over at
expresspcb.com, and an evening drawing up a PCB that will allow me to
pop a 68HC711 chip into a socket, trip it into maintenance mode, and
allow me to upload a bootstrap program that can allow changes to EEPROM.
Then I just need to map the memory of a good chip vs a blown one, and
fix the two I sank. Will post on that once it works.
I'm going to assume that it shuts off when it hits 390V, but is not temp
compensated, so it did not adjust its voltage target downwards
appropriately for the hot pack.
Right.
Aren't your battery temperatures also measured at the interconnects?
The issue you appear to be having is that the clampers are dumping their
waste heat into the battery temp sensors (or conversely, you are sensing
clamper heatsink temp, not necessarily battery temp).
Yes. The interconnects are probably the best place to measure temp,
traditionally. However we do have this little problem with the
interconnects heating up because there are a pair of clampers happily...
well clamping on either side. Maybe I should move the sensors between
the batteries or something?
It does however let me know the clampers are working.
Given the behaviour of the pack with the Dolphin, it seems that the
batteries really are getting hot, so while the interconnect temp may not
accurately reflect the battery temp, the heat being dumped into the
interconnects is making it into the batteries.
*nod* Possible.
I would expect that the largest issue you have is that the new heat from
the clampers is being dumped inside the battery boxes, and is heating up
the batteries.
This could be a problem. Plus it's now +90 degrees outside, and last
year the MC would trip out on over-temp at 40 degrees C. I do have a
hard overtemp in there at 50 degrees C now, so at least it can't get too
mad at me.
I would suggest that if you can't get the clampers out of the boxes, you
may want to try charging in 2 phases, shutting off the MC (if you can't
program it to insert a rest phase) after it hits the 340V threshold, and
allowing the batteries at least a few hours to cool a bit before
resuming the MC so it can complete.
Hm. I could do this, however it's going to increase the charge time a
good bit. Another option is to "do nothing" and keep rolling with what I
have. If it truly takes only a few minutes to get to 390 volts when the
batteries are cold, and the E-meter is accurate in it's Ah in and out
(and always coming up a bit positive) then maybe I don't have a problem
per se.
With the Dolphin you may have greater issues. Due to its low current
nature, it may tend to keep the clampers active longer (at the lower
charge rate, the pack voltage will rise more slowly and so will spend
longer in the range where the clampers are active before the batteries
reach full and the termination criteria are met), which will allow more
time for the heat from the clampers to 'soak' into the batteries and
affect their behaviour.
*nod* Even on the Magnecharger I do try to keep the clampers active as
much as possible by reducing the charge current once the pack gets to
350. This results in a quick charge to 80% or so full, but a long
drawn-out runup for the remaining amount.
Hm.....
Chris
--- End Message ---
--- Begin Message ---
Dave Cover wrote:
> how about this option. I use 2 breakers tied together
> in the rear of the car to split the pack.
> My cells will be in 3 separate battery boxes, so I won't
> have a common connection point until I get to the front
> of the car. Up there I'll use an Anderson connector so
> I can unplug the pack from the rest of the car.
Sounds very similar to my own setup ;^>
With my 120V pack I didn't have to parallel breakers, so I have a single
breaker at about the pack midpoint. The breaker is located beneath my
handbrake lever so that I can use it as an emergency disconnect without
relying on some cable arrangement to trip it.
Under the hood I have an Anderson to allow the pack to be positively
disconnected from the contactors and rest of the electrical system for
servicing.
> I also have a good fuse in the front the protect the
> Zilla. The breakers are rated for lower current than
> the fuse, so the fuse is a secondary backup.
Not so. If it is to offer any protection for the Zilla, that fuse will
have to open much faster than the breaker; it may be rated for a higher
current than the breaker, but the fuse will respond more quickly to an
overload than the breaker will. In the event of a real fault, I would
expect that fuse to open before the breaker trips. We typically include
breakers in out traction wiring as a convenenient manual emergency
disconnect (that is available off the shelf with ratings to guarantee
that it will work in the event of a failure ;^), but they respond far
too slowly to have any hope of saving the controller or any other
electronics in the event of an "event".
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
Mike, or others,
I have a solar car kit in my truck with the plans for the regen advertised.
Sadly, the regen was removed and as far as I can tell (so far), nothing
remains.
If you individually want the plans, I can email you the pdf file 5.30 MB
I can't publish to autinev from behind the firewall.
THe plans do not specify the clutch design, but does show that the electric
clutch engages the alternator and is engaged by a relay that is initiated
by the "brake lights", so does not interupt a safety device.
It doesn't specify how regen is controlled. THis seems to be the kicker
for DC systems. Do I really want to engage maximum regen by tapping on the
brake. (Or think about sliding a potentiometer to lessen or increase
regen).
Here's a crazy concept. for truck's only, how about slipping a belt around
the driveshaft to an alternator. Thus, 2nd, 3rd, or 4th gear would provide
different amounts of regen
Would this be bad for the driveshaft?
Ben
--- End Message ---
--- Begin Message ---
In a message dated 6/19/06 8:40:29 AM Pacific Daylight Time,
[EMAIL PROTECTED] writes:
<< Subj: Re: Current Eliminator News!!!!!!
Date: 6/19/06 8:40:29 AM Pacific Daylight Time
From: [EMAIL PROTECTED] (Rush)
Sender: [EMAIL PROTECTED]
Reply-to: [email protected]
To: [email protected]
Excellent Dennis, we're cheering for you!
Just went to the Speedworld SuperPro Standings page and see that you have
2189 points and Zimmerman has 1788 points. Are those the old points or the new
ones with this race?
Let us know when you're going to be doing some practice runs. Any chance of
coming down to Tucson?
Rush
Tucson AZ
www.ironandwood.or >>
That is still the old point standing,the new one will be posted by this
thursday.Mybe I will come down to Tucson in a couple of weeks to set up the
motor
and new gear ratio. Dennis
--- End Message ---
--- Begin Message ---
Christopher Zach wrote:
> Roger Stockton wrote:
>
> > What is the temp compensation factor (V/cell/degree C/F)?
>
> Something like .1mv per cell per degree C, always compensate based on
> the highest temp sensor in the pack. With a count of 150 cells per
> string, it adds up.
Must be something wrong with my math then, because the numbers you
posted are suggestive of more like 7mV/cell/degree C.
You noted that with the interconnects between 43 and 50C the MC was
compensating 339V to 360V. 339V is 2.26V/cell, 360V is 2.4V/cell, so
this is a compensation of 0.140V/cell. You also stated that the
compensation is applied from 30C, so assuming the worst case 20C delta
gives 7mV/cell/degree C compensation. Taking the lower 43C value for a
13C delta gives 10.7mV/cell/degree C.
> Well, could I get thermal runaway on some cells? Can a
> battery that is being held at a max of 14.7 still run
> away if it gets hot?
Absolutely!
> I should read up on exactly what thermal runaway is.
Thermal runaway describes the situation where a lead acid battery's
terminal voltage drops as it heats up. If the charger is holding a
constant output voltage, then the current into the battery increases if
the battery voltage drops; the higher charge current causes the battery
to heat up even more, which causes its voltage to drop even more, etc.
Hence the name "runaway".
If the charger is applying a constant current (like your Dolphin), then
as the battery heats up and drops in voltage the current will increase
up to the current limit and then hold there while the charger output
voltage drops (as the charger must lower its voltage to keep the current
from increasing). In this case, thermal runaway may not be possible, as
the the battery will heat up to some equalibrium temperature where heat
is being lost to the environment at the same rate as it is being
generated. This situation occurs only if the current limit is low
enough, which your 2A limit may be.
> The interconnects are probably the best place to measure temp,
> traditionally. However we do have this little problem with the
> interconnects heating up because there are a pair of clampers
> happily... well clamping on either side. Maybe I should move
> the sensors between the batteries or something?
Maybe. You might have to stick a reference sensor or three in the pack
first to try to determine if there is a location that better tracks the
battery temperature than the interconnects do these days.
> This could be a problem. Plus it's now +90 degrees outside,
> and last year the MC would trip out on over-temp at 40
> degrees C. I do have a hard overtemp in there at 50 degrees
> C now, so at least it can't get too mad at me.
You aren't doing your batteries any favours by raising the over-temp
limit above 40C... Most battery manufacturers don't recommend charging
above 40C and/or qualify their temperature compensation recommendations
with a footnote stating that they only apply within a certain temp range
(usually because above 35-40C something different may need to be done).
You may need to look at providing some sort of forced cooling airflow to
the battery box(es). Even 90F is only 32C, so if you can get some air
flowing through the box to carry at least some of the battery and
clamper heat out you might save yourself some grief. Be aware that you
need to ensure that the cooling air flows through in such a way as to
not introduce large temperature variations between modules near the
inlet vs those near the outlet.
Cheers,
Roger.
--- End Message ---
--- Begin Message ---
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Christopher Zach
> Sent: Monday, June 19, 2006 2:44 PM
> To: [email protected]
> Subject: Re: Odd lee reg issue on charging
>
> Roger Stockton wrote:
>
>> What is the temp compensation factor (V/cell/degree C/F)?
>
> Something like .1mv per cell per degree C, always compensate based on the
> highest temp sensor in the pack. With a count of 150 cells per string, it
> adds up.
The Hawker Genesis Literature I have says 18mv per batt per C from 25C.
http://www.enersysreservepower.com/documents/US_GPL_SG_001_0303.pdf
>
>> You've stated the answer: pack was nice and cool and behaved as
>> expected. Right after charging with the MC, it was hot, and so while
>> you couldn't get thermal runaway with the constant current Dolphin,
>> you also couldn't get the batteries up to the voltage you expected.
>
> Well, could I get thermal runaway on some cells? Can a battery that is being
> held at a max of 14.7 still run away if it gets hot?
Yep
>
> I should read up on exactly what thermal runaway is. With clampers on top of
> the battery putting heat into the battery it might be getting a bit more
> complex than normal.
>
>> Does the Dolphin blindly run 2A until some timeout, or does it shut
>> off when it reaches the target voltage (390V)? Is it temp compensated?
>
> Yes. The Dolphin is pretty stupid. I only use it every once in a while to
> make sure things are topping up.
Hawker literature says 2 amps will not charge these batteries, but will only
prevent self-discharge. (from 20% DoD.
I'd assume it's possible that from 10% or less a slow charge will occur) The
literature I refer to in this paragraph
is for the Odyssey, not the Genesis, but these batteries are REALLY similar.
>
> Now that I don't need to go to 390 ever again (thank you clampers :-) I
> intend to change the top value down to something like 367.5 or so.
>
> However my record of completely screwing up Dolphin 68HC711 chips is now two
> in a row. The problem is though you can program EEPROM through the
> DOL7 program, it won't let you change it if the chip is in fault state.
> Thus it's easy to make a mistake and wind up with a chip that will not allow
> the Dolphin to get to ready. Think chicken, egg.
>
> My solution on this BTW is to spend $10 at Mouser, $60 over at
> expresspcb.com, and an evening drawing up a PCB that will allow me to pop a
> 68HC711 chip into a socket, trip it into maintenance mode, and allow me to
> upload a bootstrap program that can allow changes to EEPROM.
> Then I just need to map the memory of a good chip vs a blown one, and fix
> the two I sank. Will post on that once it works.
>
>> I'm going to assume that it shuts off when it hits 390V, but is not
>> temp compensated, so it did not adjust its voltage target downwards
>> appropriately for the hot pack.
>
> Right.
>
>> Aren't your battery temperatures also measured at the interconnects?
>> The issue you appear to be having is that the clampers are dumping
>> their waste heat into the battery temp sensors (or conversely, you are
>> sensing clamper heatsink temp, not necessarily battery temp).
>
> Yes. The interconnects are probably the best place to measure temp,
> traditionally. However we do have this little problem with the interconnects
> heating up because there are a pair of clampers happily...
> well clamping on either side. Maybe I should move the sensors between the
> batteries or something?
>
> It does however let me know the clampers are working.
>
>> Given the behaviour of the pack with the Dolphin, it seems that the
>> batteries really are getting hot, so while the interconnect temp may
>> not accurately reflect the battery temp, the heat being dumped into
>> the interconnects is making it into the batteries.
>
> *nod* Possible.
>
>> I would expect that the largest issue you have is that the new heat
>> from the clampers is being dumped inside the battery boxes, and is
>> heating up the batteries.
>
> This could be a problem. Plus it's now +90 degrees outside, and last year
> the MC would trip out on over-temp at 40 degrees C. I do have a hard
> overtemp in there at 50 degrees C now, so at least it can't get too
> mad at me.
>
>> I would suggest that if you can't get the clampers out of the boxes,
>> you may want to try charging in 2 phases, shutting off the MC (if you
>> can't program it to insert a rest phase) after it hits the 340V
>> threshold, and allowing the batteries at least a few hours to cool a
>> bit before resuming the MC so it can complete.
>
> Hm. I could do this, however it's going to increase the charge time a good
> bit. Another option is to "do nothing" and keep rolling with what I have. If
> it truly takes only a few minutes to get to 390 volts when the batteries are
> cold, and the E-meter is accurate in it's Ah in and out (and always coming
> up a bit positive) then maybe I don't have a problem per se.
>
>> With the Dolphin you may have greater issues. Due to its low current
>> nature, it may tend to keep the clampers active longer (at the lower
>> charge rate, the pack voltage will rise more slowly and so will spend
>> longer in the range where the clampers are active before the batteries
>> reach full and the termination criteria are met), which will allow
>> more time for the heat from the clampers to 'soak' into the batteries
>> and affect their behaviour.
>
> *nod* Even on the Magnecharger I do try to keep the clampers active as much
> as possible by reducing the charge current once the pack gets to 350. This
> results in a quick charge to 80% or so full, but a long drawn-out runup for
> the remaining amount.
>
> Hm.....
Hawker Lit and EVDL past posts has indicated that the Genesis family absoutely
needs a high inrush current.
The Genesis manual says there is no need to limit the inrush current, the
Odyssey manual says that a high inrush is
highly encouraged.
from http://www.odysseyfactory.com/odycharg_a.htm
(B) Selecting a chargers current output
Maximum current
The pure lead technology of the ODYSSEY® battery does not require a limit on
the maximum output current as long as the
chargers output voltage is within the limits described in Table II. Remember
that when a fixed voltage is applied to
the battery, the output (charge) current will automatically drop as the battery
charges up. Even inrush currents as
high as four times the battery capacity do not pose a danger to a healthy
ODYSSEY® battery, provided constant voltage
charging is used.
Minimum current
The minimum acceptable charger current depends on how the battery is used. For
repeated deep discharges of the
ODYSSEY® the minimum inrush current should not be less than the rated capacity
of the batteries. For example, if a
PC545 battery, rated at 13Ah, is being used, the inrush must not be less than
about 13A.
Rapid charging of ODYSSEY® batteries
The pure lead-tin technology of ODYSSEY® batteries lends itself extremely well
to rapid charging. The graph below
shows the exceptional fast charge characteristics of the ODYSSEY® when it is
charged at a constant 14.7V, at three
levels of inrush current. This voltage level of 14.7V is very similar to the
output of a modern automotive alternator.
>
> Chris
>
Stay Charged!
Hump
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--- Begin Message ---
Kwh ? na >>> wh :
36V X 2,3Ah = 83 Wh...add ~ 12 in parallel and now you have...1 kwh
which give a spectacular 1800$/kwh, i prefer Kokam price finaly :^)
cordialement,
Philippe
Et si le pot d'échappement sortait au centre du volant ?
quel carburant choisiriez-vous ?
http://vehiculeselectriques.free.fr
Forum de discussion sur les véhicules électriques
http://vehiculeselectriques.free.fr/Forum/index.php
----- Original Message -----
From: "Kaido Kert" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, June 19, 2006 5:07 PM
Subject: 36v li-ion batteries on sale
> first, hello to everyone on the list, im new :)
>
> i thought that many of you might be interested, deWalt has brought a
> new li-ion powered product line on market which is interesting because
> replacement batteries are available too ;)
> http://www.internationaltool.com/dewalt36v.htm
> $150 for 36V battery, i have no idea how many KWhs.
> the technology inside is a123systems nanotech-enhanced li-ion cells,
> which they claim are capable of 5min recharge.
> http://www.a123systems.com/html/tech/power.html
> deWalt version recharges over an hour though with their stock charger
>
> does anyone have details on how much KWhs those contain ?
>
> -kert
>
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--- Begin Message ---
Cor van de Water wrote:
When replacing that completely with an electronic setup, the DOT approval
will usually be required or else you will not be able to register the
vehicle.
Thanks for the reply. Not having done a conversion and jumped through the
certification hoops, such an issue had failed to occurred to me. I have yet
to abandon the idea of diverting regen to ultra caps then feeding the juice
back through the system (wave of hand) somehow.
The possibility of blowing away a working Curtis controller discourages
experimentation.
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Just some future thinking here for after I get my EV on the road. All this
talk of regen lately has gotten me thinking that I'd like to add it to my
car. The snag is that I've got that worst of EV situations: a 5.5 mile
downhill stint right at the start of my daily commute each morning. One
suggestion, from Lee Hart, was to just add dynamic braking with a resistor
across the armature--but I'd like to really recover that energy and use it,
rather than burning it up as heat.
So what are some options? I have a TS Li-ion pack. Could I just charge it
to 80% each week night, capture the downhill regen each morning, then do a
full 100% equalization charge on the weekend?
Other suggestions?
Thanks.
Bill Dennis
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nikki wrote:
> What I'd really like to do is to hack the C5 so that it worked in
> pedal mode above 15mph (at which point it would be human powered so
> still exempt). Can't do anything about that of course until I get one :)
There are lots of recumbent bikes and trikes that would make far more
practical human/battery hybrids than the C5.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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I have been looking for a low-cost route to AC powered vehicle for a
while. As i dont have much experience in high-power electronis i wanted
a ready-made power board that could run a small motor out of the box. So
i found this:
a dedicated motor control MCU ST7FMC with 3KW power board development kit
http://www.st.com/stonline/stappl/press/news/year2006/p1762.htm
entire kit for around 60 bucks.
Is there a reason why this could not power a e-scooter with a small
2-2KW motor ?
What would be the main obstacles of scaling it up to around 20KW ?
In short, my question is why has AC inverter traditionally been
considered "expensive" when DSP/MCU vendors like ST, TI, Freescale,
Microchip etc sell ready-made full vector ACIM motor control kits with
full software ?
Is scaling the power stage up fundamentally hard ?
-kert
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--- Begin Message ---
So, to avoid the hazards inherent when a simple missed shift could
grenade one's motor (if you don't have a Zilla), could we use a basic
off-the-shelf rev limiter to drop out the main contactor instead of an
ignition coil?
The Pertronix Digital Rev limiter appears to have settings from 0-9
cylinders (though I've been unable to confirm that all ten switch
points are active, there were Google hits for three and five cylinder
users). So would EV use be as simple as setting it to one cylinder,
and running the yellow wire across an inductive sensor on the motor
shaft?
http://www.cbsperformance.com/catalogs/pertronix/pertronix45.shtml
Here's a page with the wiring diagram.
http://www.hillmanimages.com/912/c60-050617.html
Jay
www.karmanneclectric.blogspot.com
________________________________________________________________________
Check out AOL.com today. Breaking news, video search, pictures, email
and IM. All on demand. Always Free.
--- End Message ---
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[EMAIL PROTECTED] wrote:
> So, to avoid the hazards inherent when a simple missed shift
> could grenade one's motor (if you don't have a Zilla), could
> we use a basic off-the-shelf rev limiter to drop out the main
> contactor instead of an ignition coil?
Yes and no. You don't want to drop out the main contactor as the first
response to an overrev situation. Randy <mailto:[EMAIL PROTECTED]> at
Canadian Electric Vehicles (<http://www.canev.com>) uses/sells an ISSPRO
2-stage rev-limiter; I believe he uses the first setpoint to connect a
resistor across the potbox to reduce the throttle command significantly,
and the second setpoint to drop out the main contactor/controller KSI,
or otherwise shut down the motor if the RPM continues to rise despite
the throttle command reduction.
> The Pertronix Digital Rev limiter appears to have settings from 0-9
> cylinders (though I've been unable to confirm that all ten switch
> points are active, there were Google hits for three and five cylinder
> users). So would EV use be as simple as setting it to one cylinder,
> and running the yellow wire across an inductive sensor on the motor
> shaft?
Not typically. It depends on the speed sensor arrangement you use, but
most people tend to emulate a 4-cyl engine, which sends 2
pulses/revolution to the tach/rev-limiter.
> http://www.cbsperformance.com/catalogs/pertronix/pertronix45.shtml
I'm not sure that this particular unit would be well-suited for EV use
as the description states that it suppresses/steals ignition pulses to
control the engine speed. This would seem to be more difficult to adapt
to EV use than the ISSPRO's dry contact output(s).
Cheers,
Roger.
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--- Begin Message ---
[EMAIL PROTECTED] wrote:
>
> I am considering mounting a motor directly to a differential. that is, no
> drive shaft, just mount the motor to the front of the differential housing.
> Remove the yoke and fabricate a coupling to the motor and an adapter to bolt
> the motor to the differential housing. Maybe keep the yoke to simplify
> preload but couple the motor directly to the yoke - no drive shaft.
> Any comments on this idea?
This will work. It's widely done in all types of EVs, from golf carts to
railroad locomotives. The motor doesn't care. The main drawback is high
unsprung weight (poorer handling).
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Ben wrote:
It doesn't specify how regen is controlled. THis seems to be the kicker
for DC systems. Do I really want to engage maximum regen by tapping on the
brake. (Or think about sliding a potentiometer to lessen or increase
regen).
I like the way Solectria does it. The top half of the travel on the
accelerator is regen, the further you press it down the less regen
you get. In the middle there is no regen at all passing the middle
puts the motor under power, increasing to full throttle when fully
depressed. It takes a couple of minutes to get used to, then it
becomes instinctive. As you roll up to a light, you just lift a
little to slow down some, lift a off completely for max regen. With
some practice it becomes almost a one pedal car. I ended up using
the standard brakes only to hold it still once stopped.
Another idea would be to use kind of a slide yoke arrangement on the
connection to the master cylinder pushrod, to allow the pedal to move
a couple of inches before contacting the push rod. A pot box could
be connected to the pedal so as you depressed the pedal the regen
would ramp up and then the conventional brakes would come in.
Here's a crazy concept. for truck's only, how about slipping a belt around
the driveshaft to an alternator. Thus, 2nd, 3rd, or 4th gear would provide
different amounts of regen
No, the drive shaft speed in relation to the vehicle speed would be
the same in each gear. By driving the regen alternator from the
motor shaft you could get more regen by down shifting to increase the
alternator speed. You can also vary the amount of regen by changing
the field voltage to the alternator.
For my purposes I would think a low setting that feels like
compression braking on an ICE whenever you lift off the accelerator,
and full regen (which probably wouldn't be all that strong anyway
with an alternator) when ever you step on the brake pedal. Add a
dash mounted switch to completely shut it down if you want, and a
circuit to keep the battery from over charging.
Thanks,
Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
In medio stat virtus - Virtue is in the moderate, not the extreme
position. (Horace)
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