Freshblood

Thanks. I discharged the battery today down to auto switch-off. I proceeded to charge and the charger switched off automatically at 48.9V, which was the same as with previous BMS. The charger is pushing 54.8V(checked) So from complete discharge the BMS should be able to balance the charge. Is it possible that a discharged cell could be too low to be even considered in BMS??

Thanks for all the replies. Let's assume I soldered these points correctly and in the correct order, it might be that the range of balancing is out of wack and cannot normalize. The reason I am saying this is due to the fact that the previous BMS worked for 50 charges perfectly and then suddenly not. I resoldered the new BMS in the similar fashion. I discharged the battery today for the first time and charged again. The charger fired up and charged the pack up to 48.9V, switched off automatically and then leaked to 48V. So the same problem as before. The cells are all still good (I believe) as the problem happened rather instantly. Could some of the cell be too low to start charging at all? Like for example of the cell has dropped below 3.4V? It is a 13S4P battery by the way. The cell voltages are all over the place for example it would be S1=4.2, S2=3.8, S3=3.6, S4=4.2, S5=4, S6=4, S7=3.5, S8=3.6, S9=3.8, S10=3.8, S11=4.2, S12=4, S13=3.6.

My battery use to work and charge properly for about 50 charges over the last year. I have done about 1200kms on this battery so it has done well. Then at some stage I realized I only got half the power out of the battery and then progressively down to about 25% within a couple of charges. I did not understand as the charger would automatically switch off when full charge is reached. I proceeded to check battery at full charge and it only showed 47.9V and it should be 54.8V. That said, I checked each cell and found that some was 4.2V some 3.8V some 3.6 and so on. All over the place. I believed the BMS blew so I bought a new one. I installed but the charger does not want to charge the battery now at all. It guess it still see one of the cells at 4.2V so does not want to engage. How to now charge this battery if it does not even want to start? I checked the charger is still providing 54.8V of potential. Thanks

Hi all, Long story short, I have to reprogram my BBS02 as I stupidly built a 37V 10s6p battery instead of a 48V 13s4p battery. I wanted range instead of grunt force but did not check drive specs before :O Reason for 4p is due to space limitation. Anywho, I think I might opt for one of those programming cables rather than rebuilding. Anybody got one of those lying around I could use/buy? Need it once only I think. any advice or assistance will be appreciated.