Another Chevy Volt Lithium thread

GEM Forum
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This description, and the SuperPower diagram made me realize that the S1 terminal, which I thought had been re used to power a cigarette lighter had to be the problem. Indeed I went out and hooked it up to the S1 terminal, and everything started working again. Lights, wiper motor, etc. I could swear that this was hooked up to the cigarette lighter, and I even labelled it as such, but I must have been mistaken.

Thanks for all your help, as usual. I’m now back to a 100% functional and awesome gem car.

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OK, I wanted to get back to the installation, since the last half of this thread has been troubleshooting my BMS, and my 12v system.

I indeed had fried my BMS by placing the disconnect between the two batteries. But by the time I figured this out, I had a bunch of travel I had to do for work, and then I lost interest for a few weeks once I was back. In the meantime, I still wanted to use the car, so I hooked up an old cell phone wall wart trickle charger to bring cell 13 back in line with the rest of the cells. It took a few hours, but worked great. I put a fan on the charger to keep it under 100*

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I also had to enable the DQ charger so it would work without the BMS. Per Daves instructions above I jumpered pin 1 to pin 2 on the DQ charger pigtail.

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I mounted my shunt using some Anti static UHMW bar stock from McMaster Carr. I used the same UHMW material to make my new battery hold down. I used some cut down 2x4’s to wedge the battery packs into my under seat battery trays.

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Getting my BMS repaired was super easy. I just sent it to Dave, and he fixed it for a reasonable price VERY quickly. I contacted the manufacturer in china, and while friendly, they weren’t able to help me directly, and just told me to have Dave do it. Once I got the BMS back, I changed my wiring so the disconnect was on the B+ side, and not in between the two batteries. My batteries are now hooked up like this:

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I ended up putting two lead acid batteries up front to help with ride comfort, but man did this thing turn easy without them, so I will likely want to do something about suspension at some point. Even with the extra ballast up front, and normal cargo weight (me, 2 dogs, and a bed full of tools and gear), this thing is FAST. I’ve started keeping it in turf mode so that I’m not peeling out everywhere. I can accelerate up my steep hills no problem.

I still need to mount my BMS display. I had previously run some wire with RJ11 jacks on each end so I could put my display on my dash, but realized it actually uses RJ9 jacks. After that I will consider the lithium install a completed success.

1 Like
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Why he used rj9 is a mystery. It was my suggestion to design it using rj, but there are no decent rj-9 cables available. Rj-45 would have been ideal.
Evaluating the factory supplied cables find several ohms end to end. Dissecting it shows but a single strand on some.

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Where can you get the voltage spoof?

85

@inwo will sell it to you

86

So… I went out of the country for a month or so.

Came back to this. Any reason it would say its in “Discharge” mode? That 1.2A draw seems bad for a car just sitting still with everything shut off.

And how F*d are my new batteries? :frowning: I tried turning the BMS off, and then on again, Charger won’t kick on, and start charging… Too low of voltage?

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Damaged for sure. 50/50 If not swelled.
If amp draw is real, not good. It should return to zero with a battery lead disconnected.

I would slow charge asap. Use whatever you can find. A 12v trickle charger across sets of four?
If you have the Chargery charger, it can be set to 1 amp.

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I had the 1.2 amp draw thing before I left. Restarting the BMS (switch to “EXT”, then back to “Batt”) “fixed it”, and it was OK after that… or so I thought :slight_smile:

OK, So if I need to charge each cell individually, I can’t babysit it like I did in the past with the cell phone charger. I need something I can set and forget. Preferably something not ridiculously expensive (100, 200, or less preferably). Suggestions? I do not have a chargery charger. I have the Delta Q.

argh

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Something between 30 and 50v. It won’t take long to get the bottom 16s up to 3v. 48v.
Sooner the better. Meanwhile stop the drain. Disconnect a battery lead a unplug the bms.
I have a dozen things here, but nothing will get there asap.
Nothing I can think of in a normal home. How about 4 12v maintainers? Do you have a harbor freight near you?

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that difference in discharge voltage is strange . its not your dc to dc converter . is it your bms only pulling power from some of the cells ?

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Yes, bms is powered from the first 16 cells.
It’s a tiny amount that is normally only apparent in a dead battery.
It would take a couple months for bms to drain 3.6v to dead.

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Using a 12v/2A automotive battery charger spread across 4 cells at a time, I was able to get all cells except one up to 3.3V or higher. I have one cell that won’t go above 2.7V even after 2 or 3 times the length on the charger that the others took. Would using my 5v/2A wall wart cell phone charger hooked up to this single cell help here? (same setup I used before when the BMS drained down a single cell)

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Worth a shot. If that doesn’t bring it back nothing will.

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Update - I was indeed able to bring this battery pack back by individually charging cells, and the batteries appear to be healthy. However, I continue to have the same problem with the batteries getting drawn down. I’ve decided to give that problem its own thread: