I am running into some issue with my e-bike 10.4 ah - 48-volts battery (My battery pack is made of Samsung 26F). My e-bike has a sine wave dual voltage ( 36volts /48 volts) controller rated at 25 amp max discharge current. Lately, I was riding my e-bike and I notice on the display, the voltage was going up and down (48 volts, 30 volts, 20 volts). The power shut off afterward, I was not able to power my e-bike again. My cells are in a hailong case also known as Shark Case or Down Tube Case, the battery meter gage still light up. I open the battery when I arrived home and checked to see if the battery has a short circuit or a wire was cut or has melted. Everything looks good. when the charger is plug in it works fine. I concluded the issue was with the BMS. I ordered another BMS ( http://www.ebay.com/itm/35A-BMS-PCB-boa ... 2749.l2649
I installed the new BMS Sunday, after completion I tested the battery with e-bike and the controller power on. I then disconnected the battery and decided to add some heat shrink to the tip of the 14 wires connecting to the cells of my battery for more safety. I then tested the BMS again, the display of my ebike will light up quickly and turn off.I remioved the heat shrink and tested the battery agin, I was still having the same issue. I then used a voltemeter to test the cells of my pack the cells are ok . I measured the voltage of the cells at the pin of the 14 wire (The part that is plugged into the BMS) everything check up ok. When I charge the battery it charges ok with the new BMS, the light of the battery meter gage light up to show how much power is left in the battery. When I plug the battery into the stand on my ebike I can hear a sparkle. However, when I try to power my ebike the display will light again and turn off quickly. The battery charge OK with the new BMS (fully charged the battery is 54.6volt, when unplug for a while the battery voltage goes down to 53.8 volts due to BMS balancing the cells). I replaced the 14 small wire conecting to the BMS since the some of the wire on the old one were loose on the part where the pin that connect to the BMS is. Upon completion of the installing the new 14 wires connecting to my cells. I checked the voltage of each wires to make sure it is correctly sending the current. everything check ok.
I plug the bolck holding the wires into the BMS, then connected the battery to my ebike. I am still having the same issue. My will ebike display will power on brief (about 2 second and turn off) like it did before. The cells of my battery pack are spot wielded, I already checked the spot wield and there is no damage.
I initially thought my controller could be the issue. Therefore, I used my back up controller Sinwave dual voltage (36volts / 48 volts - 26amp max current discharge) and the stock controller (The stock controller that came with ebike is not compatible with my Sinewave controller display, it used three led light on the throttle to indicate power and the battery gave level) that came with my conversion kit (the stock controller is 48 volt controller - 26 amp max discharge current). I still have the same issue. I replaced the positive and negative wire of my pack just in case, I am still having the same issue. I have a 36 volts battery as back up and it work fine with my controllers (My 48 volts battery is my main battery pack ).
I am now thinking the new BMS might be defective or maybe I miss out on something. You suggestion are welcomed.