2014 Gem

Interesting, I thought a 2002 would not run over 94v. Even with spoof.

96V is the cutoff, absolutely confirmed. Thats why I was charging to 95.9V

Bms is fine for you. I love it. But, once things are dialed not needed?
See how it goes on yours.

Im not a pro by any sense, but I do try understand and retain as much as possible. For someone looking for a more plug and play install, that would be good. Pre balance the cells and put the board together. 28 cells fits really nice under the rear seat. There should be no need for anything else.

This looks interestingā€¦

https://evparts.com.au/ev-power-bms/bms-cell-modules/lfp-voltage-balance-board.html

Same thing. Neater package. 1/2 the current.
Price is good.
Might be the way to go.

Says itā€™s only suitable for 12v systems though. Would be perfect if we could find one rated higher.

Thatā€™s odd. Shunt balancers work locally. They donā€™t see the pack voltage.
Iā€™ve used these. The led comes on when cell reaches 3.6v. When they all come on at the same time, you know everything is perfect.
image

Ok, getting some better numbersā€¦

I noticed towards the end of the charge one battery started climbing rapidly. Got to 3.9v and I shut it off. It did drop back quickly to normal 3.35v. Is that normal or something to keep monitoring? High voltage protection is set to 4.19v

Thats what your looking for. Drain that cell untill it no longer goes high. Stop before it goes over 3.7v.
Once you can finish charge with none over 3.7 youā€™re good to go .
On the other end stop when a cell goes under 3volts.
Thats all the range you can get. There is no reason it should not take 60ah to refill it.
Im hoping most of the cells are still ok.

I think Iā€™ll let you use a shunt balance board. Makes it easy.
Charge untill a few leds come on. Wait for them to go out. Charge again. Repeat untill all the leds come on at once.

Oh, crap. I just read 4.1v. Heck no! 3.7v absolute maximum. Anything over that is killing the cells.I set mine at 3.65v

I believe that in power supply mode thru the bms, it will charge, balance, charge, balance until all are full.
In charge mode it wonā€™t restart.

Defiantly no good with the restart in power supply and Life mode. When that one cell gets too high it shuts down the charger and it says connection brake. I think thatā€™s why Iā€™m never getting full charge.

Thatā€™s what it needs to do to protect battery. You will need to drain the high cell and restart charge or charge the low ones to catch up.
Once all are charged it will stay in balance.

You think it would be wise to bottom balance?

Thatā€™s the dilemma.
Canā€™t do both top and bottom. I bottom balance and charge until the lowest capacity battery is full. That will be > 60ah and all the pack can deliver.
A bms will try to top balance and get them out of step. With a bms, you are committed to top balancing.
Either way is valid.
There are many anecdotal experiences online using LiFePo4 for years with no bms and bottom balanced cells.
The pros use a bms.
Iā€™m worried that you may tire of this soon? :frowning:
I ship batteries bottom balanced and about 10ah added. I hesitate to have you change horses, now.
Are you up for it?
Add to the mix that a couple batteries may be damaged. You should have any weak ones culled by now though. :slight_smile:

Not getting tired, but just when I think Iā€™m getting somewhere another wrench in the works. Frustrating.

I reached out to that company in Australia and explained my setup. I like those shunt boards.

I think I have a good idea of what cells are acting funny at this point.

Actually I may be getting some similar ones in.
I might have read that they balance stand-alone.

I wonā€™t know what it is until I get it.
4 pallets from a defunct EV company.

  1. 18 chargers, Elite Power Systems. One is out of box, 17 in original boxes. It is 86V, 29 amp output.

  2. 41 of the Elite Energy Management Boxes.

  3. 13 Current Sensors LEM.

  4. 241 of the Elite Power 4-cell Sense Boards EMS-4SB-V7 (Black Coating)

  5. 624 of the Elite Power 4- cell Sense Boards (Green)

  6. Elite Power Systems programming device and display

  7. 270 Blue Boxes of ā€œFLX24CHBMS 24 Cell BMSā€.

New toys!

I spent the day fitting the new roof rack, and went for a quick spin. The two funky batteries seem good for now. I charged then backed them down to the packs average and let the bms equalize.

I also turned down the controlled acceleration and min field current. The batteries were about 3.25, when accelerating they donā€™t sag as much, but sill hover a little below three. They do spring right back to 3.2ish while coasting.

What should battery remaining capacity and total circulation capacity be set to?

It wonā€™t make any difference for you. The remaining capacity sets the current reading, and tracks usage.
It only works with the ammeter.
You can use it to measure charge if you reset it.
The full load current can go through the 300a bms, but it will trip out during hard acceleration. unless you tame the controller current.
Iā€™m going to disconnect mine. Every time Iā€™m in a hurry it trips.