I wired up my standard chinese smart bms the other day to test out a couple things. I then took the system apart to clean things up and improve everything. When I hooked it up today it jumped into "short circuit protection" mode and I don't know why. I have the negative going into B- and then from C- to the negative busbar. When I probe the balance leads I start with 0 and 1 and read 3.9v and as I move the positive lead along the JST connector it goes up by just under 4v all the way to the 15th cell. I have double checked that a couple times and I keep getting the same reading.
Did the BMS fail? When I connected it earlier today I made sure there were no loads to power immediately. The victron mppt is the only thing that would power up. I do have a victron BMV shunt between the negative of the pack and the BMS. The + lead for the shunt is connected directly to the positive of the battery. That lead is fused. The BMV reads the expected voltage (59.6 for a 15s pack that is charged to 4v)
Well, I'm not sure what happened. I didn't change any wiring. I disconnected everything and then probed out the wiring to make sure I had it right. I hooked it back up and it works. That is a little bit concerning... But I'm glad it is working.
Did the BMS fail? When I connected it earlier today I made sure there were no loads to power immediately. The victron mppt is the only thing that would power up. I do have a victron BMV shunt between the negative of the pack and the BMS. The + lead for the shunt is connected directly to the positive of the battery. That lead is fused. The BMV reads the expected voltage (59.6 for a 15s pack that is charged to 4v)
Well, I'm not sure what happened. I didn't change any wiring. I disconnected everything and then probed out the wiring to make sure I had it right. I hooked it back up and it works. That is a little bit concerning... But I'm glad it is working.