While charging…
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Rip that group. Check all welds would be my first step.
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Thx, I guess I won’t be riding today…
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Im guessing loose nickel
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Hey guys. Just wanted to link this in case anyone was interested.
It’s for sale: $350 plus shipping
I usually just add as many welds to each cell that I can unless there’s very obviously a set of welds that’s loose. More efficient imo and if one set of welds is weak, there are often others in the group.
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This could just be a BMS issue. I’m fighting with an 18S BMS on a specific setup doing this same thing to me which charging.
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Yeah i just had the same thing with a brand new 10s10p with an LLT wired for discharge. I just ripped the bms and suspect group and replaced them both
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LLTs have been spotless for me so far, I really hope it stays that way.
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Yeah i really don’t know what the problem was, but was easier just to replace the potential problems rather than troubleshoot
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I was out for a ride to see what it would do under load and it sagged from 47.5V to 42V triggered the mismatch alarm (0.23) on my metr pro. BMS is wired for charge only. I’m also using battery modules so it could be a loose bus bar or something. I’m going get a kweld and use nickel. Question… can I use my cells from this battery to rebuild using nickel providing the cells are good I plan to check the IR of each cell before doing so.
Shouldn’t be an issue as long as you leave the cells in the same groups. Additionally, the IR measurements should be taken w a grain of salt as your mutlimeter won’t accurately measure it. The only thing that the measurement will really tell you is if one cell’s IR is significantly different than the others, that cell might be faulty or at least problematic and possibly unsuitable for a high current discharge.
Stated differently, it’s not a deal breaker if your cells are measuring ‘out of spec’ as long as they’re all similar IR. You should measure each cell multiple times as well and make sure you’re getting relatively consistent results.
Kweld is a good choice 
I’d also recommend springing for some pre-cut nickel. Makes the job MUCH easier.
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Thx bruh, This helps me a lot.
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Arcing…maybe, why, how? I bet one of the cells is loose inside the module. That screw looks like it’s sitting higher than the rest. Is it safe to tighten it back down, Will I short it with the allen key? Maybe it’s better to just spend my time ordering a kweld, pre cut strips and a PCB from @DuckBatterySystems.
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If it’s arcing the screw is loose and you need to tighten it, assuming there is nothing in the way inside the cell holder. Are those nese modules? I have seen now several instances where these things have a poor connection to the cells inside.
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Yes NESE cells. I’ve seen the arcing problem as well.
When applying a load to the battery should the amp draw be uniform across all P groups?
Yes.
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I got a smart bms from llt and it has to wires for a power switch. Do I have to wire a switch in or can I just ignore those wires? Thanks