austrian_painter
New Member
A PowerTube 750 wouldn't charge anymore. Neither in the bike nor directly at the charger. No signs of life. No LED lights, nothing at all. The bike also wouldn't start. No LEDs, nothing. Completely dead. The dealer declared the battery completely dead and insurance paid for a new one. They just left the broken one lying there. At some point, my colleague asked me to take a look at it... Opened the battery, removed all screws, those long ones... then with a rubber hammer and a bit too much force... Measured all cells... they all had something between 36 and 41 volts. So completely unbalanced. That's why the BMS probably refused service. Then I set my lab transformer to 42 volts and directly connected it to the main plus and minus BEHIND the BMS and charged the cells "blindly". The ampere display on the lab transformer kept dropping further and further, which told me that the battery was charging and slowly getting full. In between, measured the cells individually again. At the end, they were all at about 41.5 volts. Then I reassembled the battery and VOILA, it immediately started working again. It properly charged and started immediately in the bike. Just wanted to share my experience with you. Maybe it'll help someone someday. Greetings.
