Lithium battery in a 2002

I bought a LI battery from Inwo last fall. Volt (I think) 72V package with a BMS. This was something he had on the shelf and delivered as is. I understood. Everything worked at first on the bench but then I got some opens in the BMS ribbon cable connector on the larger half of the pack. Any tips on fixing this?

My thought is to bypass the ribbon and attempt to connect wires to the copper connectors between the cells. I am just not sure how since they are pretty thin. Also there is a thing in the ribbon cable for each cell. Does anyone know what that is?

Car runs well on the pack, but I did not mess with it much in the fall. Time got short.

One more thing, I need advice on mounting this pack in the car? It can’t ride around on the passenger floor forever.

Soon I will get the car our of the winter shed, pull the hundreds of pounds of Lead, and start playing around with this ~4kWh pack. I want the BMS to work to control the charging. Trying to use the charger in the car but it needs the BMS control.

Remind me what you got. Pictures of battery and bms will help.

Where are you located? You sound like you could use some inspirational help.
Or at least someone to come over and help drink your beer.

Sounds like a Volt battery. Even if I sold as-is, I won’t let you hanging.
Bigger half. 16s and a 6s maybe?

@Inwo - What about this? Does this sound familiar?
Is the little thing possibly a Fuse?(in which case it may point to issues downstream)

Everything worked at first on the bench but then I got some opens in the BMS ribbon cable connector on the larger half of the pack. Any tips on fixing this?

My thought is to bypass the ribbon and attempt to connect wires to the copper connectors between the cells. I am just not sure how since they are pretty thin. Also there is a thing in the ribbon cable for each cell. Does anyone know what that is?

Possibly. the 16s modules have internal 1/2a fuses. A chargery bms is 1.2a balance.

Yep they are 22s Volt cells. I just soldered new wires to the fuses on the ribbon cable and the BMS now works. It was raining so all I did was back it out and back in. The BMS indicated around 3.5 to 3.6 volts per cell. I set the Zivan Charger to Trojan F setting nominal 85.6 volts. It charged to almost 86 volts at 9.7 amps then backed down to 3.8 amps and reached 87 something before I stopped it. I think it would have reached 88 volts. Good news is this should charge enough for me to have enough range for my use. Bad news it the T2 controller code -16 overvoltage.

I guess I need a voltage spoof for this 22 cell battery to stay under 86 volts and not so much I drop to 69 volts. I think 6 to 8 volts drop would be the right range. I could build or buy one. I would need to know what pins to modify and what size and manufacturer pins are in the plugs.

If there is a MM magnet available to let the speed roll up about 20% to 50% higher I would like to get one.

The MM will adjust in 15 steps up to double speed limit.
Send $150 for both spoof and MM.

I would build a 4v spoof

OK, I built a 8 volt drop for a spoof on pin 1 and everything works well. Zivan Charger on “F” for high voltage trojan will get cells to 91 volts. Some balancing occurs near the top. Cells are balanced to within 0.012 to 0.040 volts depending on where in the cycle they are. We will see if this closes up with a few cycles but it works as is. I drove around town yesterday from 100% to 75% charge. Went as far as I will ever go in a single trip. Factory dash gauge was at 100% the whole trip but dropped to 95% as I pulled in my driveway. The car easily reaches 28 mph except on hills. Now goes 23 uphill where it used to do 19 on lead. I think that is at the limit of the motor or controller. Annoying thing that is worse now with Lithium is the pedal to the floor on any sort of downhill the controller alternates between mild acceleration and full regeneration braking in a 10 second cycle. It did this on lead batteries too. It does the control smoother if I let off the Pedal slightly, but I lose a precious mph or two. I am monitoring the batteries with the display for the BMS, but I will probably remove it after a few cycles and let the BMS do its job on its own. Then I will just use the display as a service tool every few cycles. If the Dash gauge gives me some reasonable warning of low charge I would likely not even need the BMS at all when I get further into this. but it does give peace of mind at this point. The BMS does drain the battery slightly at rest. Without the BMS and with the battery switch off the pack does not seem to discharge at all. I installed a bypass switch on my Spoof, so if the controller cuts out on low voltage I should be able to activate a reserve to get home. I have to do more driving to test this function and discover how the bottom end of the charge behaves.

Quick Summary
22 cell 55ah Chevy Volt from INWO (one off, not a regular product)
BMS including display from INWO (one off, not a regular product)
2002 4 seater GEM car
Stock 5Hp motor (Original ?)
Stock T2 controller
Stock Zivan Charger with Trojan / Gel rebuild sticker for “C” and “F”.
Home Built 8 volt spoof on Pin 1 of 23 pin plug

I plan to add a MM speed spoof to see if the top end behavior improves on hills. If it does not help, I might get into T2 programming but that opens up a new bucket of fish.

BTW my one trip without the heavy batteries did not show a big difference in the ride quality. It still sucks. It just does not seem worse. I have all 55ah of batteries under the hood. I did keep the long battery wires in series as I kept the factory battery disconnect in the circuit. Years ago I had mounted the switch through the panel where the charge plugs in so I can switch it off with the seat in place. With the wires already there I thought a disconnect switch away from the business end of the installation might be a good safety practice.

So this is as close to stock 2002 GEM can be and still run 90 volts of lithium. I think no matter what, the additional voltage provided by 22s Lithium ion or 24s LiFePo, or 7s 12 volt lead batteries, is a worthwhile modification to these cars to make them run to at least close to the minimal promise of the original manufacturer’ sales brochure. I think the stock build met the manufacturer’s real original goal (which was to meet a quota for number of Zero emissions vehicles built).

If you read this far, here is the ironic purpose I use this car for the most. I drive to the gas station to get real gas for the boat and the lawn mower.

It really sounds like you are bouncing off the speed limiter on the flats and especially obvious going downhill. You should have installed the MM long ago. It probably won’t help on uphill performance since it is not a power adder.

Depending on how you set it, it may not go into regen at all, so watch the speed going downhill. Over revving the motor might fly it apart.

If anyone wants to copy this. Buy a 16s Volt or Spark module and a 6s Gen1 Volt module.
22s is a great configuration.

Sounds like it is working well. Suggestion, you are charging the cells too high. If you limit them to 4.0v they well last 50% longer or more. Gm limited the maximum cell voltage to about 4.0v to increase longevity and increase safety

I will set the Zivan back to the Gell setting and see where it ends up. The “Hot” Trojan setting charged higher than I thought it would. Label says 85.3 volts, That is about where the charge shifted from 10 amp bulk to 3.8 amp till it finished. Topping out at 88 volts might be adequate for my driving around here. But the BMS balancing does not occur at these lower voltages. Maybe I can access its settings, but that will take more research.

Zivan profiles are burned onto an eeprom. When I wanted settings changed I had to drive out to electric conversions in Sacramento and buy a chip with new programming and swap them. I think it was like $30 cash and I kept both chips. No way to plug into the charger and reprogram it as far as I know.

Now that I think about it, I never did try to read one of the chips on my programmer before I gave them to Rodney. I can’t recall why exactly, maybe I was having problems with the software at the time or I did and that hard disk crashed.