Posted this earlier but I figured I’d give it its own topic to get the proper help.
So I decided to upgrade to 30q to combat voltage sag. I just switched the cells and re-wired the bms. When I first plugged the battery into the speed controller it came on and ran fine. Now this morning after charging the cells, when turning the board on , the esc beeps to show power then the whole board shuts off. The only thing different from when I tested last night is I crammed the battery case cover back on. The only thing I could think of happening was some sort of solder joint inside the battery broke when I stuck the case cover back on. The weird thing is my multimeter still shows 37 V so if the battery was messed up why is it still showing voltage? If the esc was messed up why would it start up then shut back off?
If anyone cares I fixed this. When snapping the case back together, a plastic piece was pulling off one of my terminal connections. It’s strange that the multimeter was still reading voltage.
It’s all about the sag. The old batteries would have significant loss after just a few seconds of going uphill. Now I can blast up but it will still suddenly slow after going full throttle uphill for about 30 sec. Havent tried the range yet. This is the dual hub version btw with a replaced esc to the dual sine sold by diyeboard.
No. If I do that the board will cut off all together. This is different. It just slips when I do long brakes like going slow down a hill. This is at all battery levels.
Yeah so the battery rattled the connections loose again. It’s because I was trying to do all the soldering/ spot welding without taking the bms out of the case. The wires are cut to extend to the terminals and not a bit closer. Ideally I’d be able to find a small 8 pin bms wire to have more to work with when I put this back together again. May just have to get rid of the case because of the cramped space.
So maybe someone can tell me what is going wrong. Ever since I switched to the 30q cells the board will work fine then about 30 min in it just cuts off entirely. If I push it I can hear the esc beep to try to power back on but the battery won’t supply it with power. After a couple of hours it will start to work again. This all started after switching to the 30Q cells. I’m new to this. Is the stock batteries bms somehow responsible? Any other ideas would be greatly appreciated. All the solder spots are good. It seems to happen right after getting recharged all the way but that may just be a coincidence.
So instead of a pin connector, the balance wires are glued onto the bms chip. I think the reason it was cutting out is because a couple of the wires were coming loose.
Besides running in a slower speed mode that draws less current no. Your other option is to use cells win higher CDR. The higher the CDR,l (in relativity to the current being drawn by the board) the lower the voltage sag.
