If one of the cells is missing, the bestech wont turn on. But maybe something happen to one of the cells under load, when you ride.
What are your current limits at. If youāre drawing too much for the cells you could be experiencing insane voltage sag
Ill report back once homeā¦ Really appreciate the help here guys. If the balance connectors werenāt on well, the bms wonāt turn on, but wouldnāt that mean my entire system wonāt turn on?
Sorry to disappear like that. Family stuff blah blah lol. So I removed the BMS and charged my pack to 90%. It sort of charged more than that and the first group of cells were at 4.31 V. My battery guy us replacing the first group right now. Iām getting it back tomorrow. Would I be able to hook my 42 v battery charger to my vesc and use as a power source to look at my settings or is that a bad idea? @Jinra
Also, does the Regen setting affect how much it well the board brakes?
@Jinra, got my battery back, all is hooked up minus BMS. Gonna test tomorrow. Hereās my VESC setup:
Any help and insight will be greatly appreciated.
Be careful overcharging cells like that. Li-ion is a sensitive chemistry that does not like to be overcharged and it can damage the cell and shorten itās cycle life.
Battery regen affects the high speed braking response, motor min affects low to mid-high braking. If those settings are for a single VESC you can go up to +4A per parallel cell, though with how regen works you can afford to go a bit higher as well for better braking.
Ok. So you figure the battery min is probably ok, but Iām overcharging? By that do you mean battery max and motor min/max? Iām pretty sure thatās what happened. Screwed up a group of cells from over taxing. Would definitely like to avoid this happening. What parameters would you input? Thanks
youāre settings are okay from what i see. Youāll need the bms to prevent overcharging on your parallel groups.
When youāre speaking of overcharging, are you referring to when Iām riding and using the brakes? Or when Iām actually charging the battery? I have a smart charger. I can select 80, 90, and 100% charge. And itās voltage is specific for 10s Li ion. Donāt get me wrong, I plan on having a BMS one way or another, not sure if my bestech is toast or not. Have another coming. But Iām not certain where it really comes in handy stillā¦
When youāre charging the battery. You mentioned that one group was at 4.31v which is very bad for the cell. Youāll like never overcharge from regen as the energy you get back is minimal.
True. So strange it did that. To me, that seemed to be more to do with the cells in that group being bad. But I just donāt know enough yet about battery charging and BMS circuitry to be sure. Thanks for your help man. Appreciated.
If you had a BMS attached it wouldāve stopped that parallel group from going over 4.2~v
But how come just the one bank? All others where at 3.9 V? That said, it is the pack that that the main negative lead comes off of.
it could be that a cell in the paralllel group became detached meaning that group is charging faster than the others due to less mAh.
Very possible. Looks like 3 of the batteries started venting at some point. Still leaves me wondering whatās going on? Iāll have it all back together to test ride tonight. If that hitchy feeling is gone then Iāll have to assume my BMS was screwed up? No point in drawing conclusions until Iāve given her a bit of a test drive.
Did you finally diagnose the problem? Iām having the same issues! Is it a faulty bms? Or a problem with some of the batteries? Thank you
Damn dude, that was a while ago! From what I remember, that batt caused a few problems initially. Had the battery repaired (bad cell in first p group), but didnāt bother with the bms for a while. That worked great but obviously not safe. Next season used a different bms and had no further issues. So it could be a battery issue (most likely) or a bricked bms. How long you been using it for? Who built it?