Hi, one of my new 48v 200ah batteries shut off and won’t restart. I was checking the screens on all of the batteries and just after I checked one of them, 52v charging at 28amps, the screen shut off. There was no power at either terminal but the connections inside showed 50.2v. The voltage has slipped down a bit over the last few days to 49v and it still won’t start. I’m assuming I have a BMS problem. What is the best and easiest way to test it? Also to charge it up could I bypass the BMS and connect directly to the inside terminals and watch it while it charges? I’ don’t want the voltage to drop down to the point where the cells are damaged. All cells test between 2.8 and 3.0v. All suggestions will be greatly appreciated. the dog
Hi, sorry we cannot help without knowing what type or brand battery you are using?
Hi, Sorry, I guess my brain stopped! They are Turli Lifepo4 200ah 48v batteries. Turli is a Chinese company 2years old selling through Alibaba, the salesperson was super helpful and there were no communication problems with him. The BMS allows for 100amp charge/discharge. They have a screen that displays volts, state of charge, amps charging/discharging, BMS status, BMS faults, over voltage/under voltage events, cell temperature, cell voltage, battery overall temperature. I just happened to be checking the batteries one morning and had just checked this one, it showed 52v and was charging at 22amps and the screen went dark and all the lights on it went out just after I checked it so I know it wasn’t at low voltage shutoff or over/under charging.
It sounds like your 48v 200ah solar battery might be having a BMS issue, causing a shut-off despite showing voltage. To test, try disconnecting the BMS and connecting a charger directly to the terminals, monitoring closely to prevent overcharging or damage to cells. Check the voltage regularly, ensuring it doesn’t drop too low. If the cells remain between 2.8 and 3.0v, it’s a good sign. But remember, safety first—avoid overcharging. If unsure, seeking professional help or contacting the manufacturer might be wise.