12s lithium balance charger project.
5 amp 4.2 volt.
Modular repairable design.
Only 8" X 11" X 2".
Passive balancing project.
As I’m not smart enough to do the math, this is a “see what happens” project.
Put 10 ohms across each cell while charging.
Charging with 2.2a bulk charger.
My idea is that high cells will dump more power thru shunt resistor. Low cells will dump less.
~200ma thru each resistor. ~1/10 the charging current.
Not efficient I know. But will it work?
Interesting.
I use the Mini-BMS boards on my GEM LiFePO4 cells. Similar passive balancing concept but the bms board applies the shunt resistor to the cell only as it is approaching (but not yet) peak. This allows the other cells to catch up (that don’t have the shunt resistor “enabled”). These bms boards have worked excellent in keeping my lithium cells balanced.
The other advantage of using some bms board (over a resistor) is that you can set it up to shut off the charger automatically when a cell reaches peak.
I use CALB cells in my GEM but Mini-BMS makes bms boards for Leaf/Volt cells too for about $13 each.
RWD
Most of my projects are just for fun.
I run 24s in my gem. Looking for cost effective solutions.
This is 18s LTO in my scooter.
It’s never been balanced, just abused. This test will tell me how much current it takes to catch up.
Cell chargers are working pretty good.
Down side is that they taper down to 1/2a toward the end. Extending the time it takes for top balance.
Resistors work like cheap bms systems. Helps keep balance, but as they only conduct a few ma, can’t bring balance back from “bad”.
I’ve tested, and am in the process of have circuit boards made. 1 to 12 cells.
Adjustable from any voltage 2v to > 10v.
Hope is that it can be plugged into bms/monitor port and discharge each cell to set-point. Ie. bottom balance.
Or it can be left plugged in and batteries can be charged with bulk charger. Each cell will bypass at set-point to top balance.
Bulk charger turns off independently at it’s own programmed limit.
Such as QuiQ with lithium profiles.
As it is completely independent and self powered, it’s easy to connect. No external interlocks or wiring.
Every thing will work the same with or without it.
Leave it on or use once a month to balance pack.
Use two for up to 24 cells. Lifepo, LTO, or Li-ion.
Balances from 1 to 5 amps. More if needed.
Board, as of now, is about 3.5" square.
Usually take a couple weeks to get them built.
Then looking for guinea pigs! 
For the anti-bms crowd. This is not a bms. It is a high current shunt balancer.
In theory it would work on lead!
12 X 20t pots
12 X led (on when bypassing)
I’m down to try one out. Currently my charging with a standard delta q had kept my cells with in range. But it would be nice to keep them closer in voltage. I’ll take not of my cell ranges and post them here.
Have a bunch of these coming to monitor cells.
Only does 6s each. Need two per balance board.
4pcs to monitor 20-24s.
Only about $10 each.
I’m betting they’re fine.
Making some progress on testing, before boards are done.
Have one mocked up. Moving it from cell to cell set at 4v.
Discharge mode. @ 1.5amp. Bringing each cell to 4.00v.
Led goes out when finished.
Clothes pin holds thermocouple.
Other leads monitor voltage and current of each component.
Testing shows ~ 6hrs to lower charge ~ .06 volts.
Overnight should balance all but severe cases.
Grant, will that work for you?
It can be scaled up easily. Faster dump means more heat.
Also bms cables may not like more than a couple amps.
Boards are in.
Hmmm
Look pretty naked.
How does your DQ programmer work for you? Thinking of getting one.
Rodney
Perfect!
Let me know your plans.
Our DQ guy has chargers ready to go for $250.
Just populated 1 of 12 regulators. Missing some parts yet.
I believe this will be something that every lithium user will want.
Once a month, plug it in overnight, to balance pack.
If I stay with it.:eek:
Testing 2 of 12 shunt balancers on 12s LTO 60ah pack.
Have all the parts. Next step, connect all 12.
I can get a better picture of plywood battery if interested.
3 of these makes >72volts ~ 100lbs 60ah
< $700
Altairnano LTO = Safest Lith. chem. That’s what they use in airplanes.
Are you saying you can supply an entire package for 700 bucks? Get set to be trampled.
No, I’m just trying to get some attention. 
Yes, I would sell 36s for less than $700.
I would offer my experience in making a useful battery.
It needs a container of some sort.
My testing is done with plywood.
Next to Chevy volt battery.
Top showing tab connections with alum. backing and pop rivets.
A full box of 12 60ah pouches.
36s = 54-99 volts.
Any charger setting will work.
Charge at 300amps if you like. <15 minutes :eek:
Whether it is suitable only as a hobby battery project or a 20year solution depends on skill mounting and connecting.
Dave,
just looked up the specs on the manufactures website , these things are animals .
15 minute charges , 16,000 cycles . wow.
are these used cells ? have they tested well ? would like to see the connectors you are using .
They are engineering samples.
All have worked great so far. Even the trashed ones with obvious issues take charge, after sitting dead for a year.
A few hundred left.
I have a few completed 10s 60ah that are new, marked B-stock.
Have 6s (12v) and 8s smaller factory packs. About 12ah. And a few hundred pouches.
Had a bunch of 360ah. They sold right away.
I quit this 12s project after 12 pouches. It is less than ideal. Used some oddly machined alum. scrap, for backing plates. They had holes in the right place, for pop-rivets.
Cleaned tabs with ss brush. Coated with anti-ox. Riveted with a terminal for BMS.
The smaller tabs I just rivet with alum. washers. Some solder them. Tough job with aluminum.
Welding is best choice. I’m not there yet.
If I could find a good welder, could make packs for people.
Hello INWO,
I have acquired some Chevy volt battery packs and am anxious to try them in my 2005 GEM E4. Do you know where I can get a Controller manual? I see that you have been able to reprogram the controller. Can you supply info? I’m also very interested in your voltage spoof.
My DQ charger is not programmable (according to DQ). I’d be very interested in your DQ Guy’s chargers. Are these programmable? What equipment is required?
Thanks, Ed.
[quote=On the Fritz;32321]Hello INWO,
I have acquired some Chevy volt battery packs and am anxious to try them in my 2005 GEM E4. Do you know where I can get a Controller manual? I see that you have been able to reprogram the controller. Can you supply info? I’m also very interested in your voltage spoof.
My DQ charger is not programmable (according to DQ). I’d be very interested in your DQ Guy’s chargers. Are these programmable? What equipment is required?
Thanks, Ed.[/quote]
ED,
you well be very happy when you do this . a couple of things . your DQ is programmable but DQ wont do it . there is a guy in Portland that does them , about $75 . the 2005 controller is the least programmable of all years (t3) everyone that has tried has had some success but not as much as other years . Houseboater just finished doing one , check with him.
that said these motors do respond very well to the higher voltages of lithium so with this and the large weight reduction you well see some big improvements . to my knowledge no one has done a t3 lithium conversion , so I well be following yours with interest . start a new thread so we all can follow it . your going to love it when its done .