It’s been a while since I’ve torn down a battery pack! The last one I tore down was a BionX 9.6AH 36v pack, back in June. I’ve been busy since then, and have rebuilt a few packs, but I haven’t played with anything new.
This is a companion discussion topic for the original entry at https://www.sevarg.net/2016/01/10/trek-valencia-ride-bionx-battery-pack_9/
Very nice to find this on the net. I have recently bought two of these bikes in very tidy condition, however, one of the battery packs was dead and wouldn’t take charge. I opened the case with the same difficulty you describe, and then resurrected the battery pack by gently feeding the battery direct from a home built variable transformer charger. After gently teasing the voltage up to about 25v over an hour or more, I was able to plug in it’s proper charger which then began charging the battery. It charged for about 4 hours then shut down with the green light on. The battery now sat at 45.7v, I left it to settle overnight and it still read a healthy 43.5 v all the next day, so I re-assembled the pack and tried it on the bike. The system wouldn’t light up so decided to look at the electronic board inside the pack. Examination showed that D19 on the underside of the board has exploded. This diode is straight across the motor feed pos & neg. Do you know if this is a zenner or not please? I doibt if this is the only issue, but I can confirm that the bike works ok if I swap the other bike battery on to it. Also, the battery cells look ok under the black outer shrink wrap and they are holding charge, so I am convinced that it is just the electronic board that has failed. Do you know where I might get either a new or used identical bike battery, or just another board?
Make sure that’s not dropping… that’s a pretty major draw on the pack to drop that far overnight. Lithium should just stay where you leave it off the charger.
I have no idea what that diode is, sorry. And I’ve no idea where any of those boards can be found. I don’t have any left.
Thanks for the reply. I found the reason for the pack being totally flat when we first had it, whatever has popped on the board somehow switched on the bike lights. That wasn’t apparent until I had hot charge back in the cells in its dismantled state. The battery pack is holding good charge now, so I am confident that all I need is a new board (if I can source one) it’s a big world out there, so there likely will be one kicking around somewhere. I found two other blown chips on the board, so it’s well chuffed.