Weird BBS02 power loss problem, solved :)

[Fordulike]

Got caught out in the mother of all rainfalls today. I usually head for cover in these instances, but I wasn't near any and the bike got a drenching. Heading home, the power was intermittently cutting out, then it finally cut out totally. The display was still on, but the battery symbol was flashing.

Thinking it could be water ingress in either the Bafang or the battery, I switched everything off and pedalled back.
Phew, with me wet through and no power, it was friggin hard work

Anyway, dried the bike off at home with the wife's hairdryer. Got little hair myself, so big thanks to her

Battery checked and all fine.The problem still existed, with the error code 04 on the display and battery symbol flashing. After Googling code 04, it showed 'throttle no homing'. Strange, as I have never had a throttle connected.

After some head scratching, I found the problem. As I haven't connected a throttle, I just leave the connector wrapped around the handlebars with the end dangling. A sneaky little drop of water had got into the connector head and was shorting the pins. This was confusing the Bafang and causing the error code.



A lesson learnt the hard way

 

[Deleted member 4366]

You were lucky. My friend got water in his throttle and so he experience intermittent cut-outs. It must have compromised the 5v, which messed up the hall signals. He tried to carry on, but then the magic smoke appeared from the mosfets.

You have to take care with cut-outs. Never try and give a motor power when it's cutting out. Often, it's not the power to the motor that's been cut. The controller is trying to feed full power into what's effectively a jammed motor. If anything interferes with the controller's timing, like a bad connection to a hall or phase wire, the motor can't turn so the controller blows.

 

[D C]

Does that mean that a motor without hall sensors is less likely to be a problem?

Dave.

 

[Deleted member 4366]

Everything has advantages and disadvantages. I'd always use a hall sensor motor, given the choice. You just have to make sure that you have good connections and keep the water out of your electrics.

 

[Fordulike]

Yep, totally agree with d8veh, it was my fault for not capping that unused connector.

 

[Nealh]

A bit of glued heat shrink doe the trick on any end feeds.

 

[mountainsport]

Got caught out in the mother of all rainfalls today. I usually head for cover in these instances, but I wasn't near any and the bike got a drenching. Heading home, the power was intermittently cutting out, then it finally cut out totally. The display was still on, but the battery symbol was flashing.

Thinking it could be water ingress in either the Bafang or the battery, I switched everything off and pedalled back.
Phew, with me wet through and no power, it was friggin hard work

Anyway, dried the bike off at home with the wife's hairdryer. Got little hair myself, so big thanks to her

Battery checked and all fine.The problem still existed, with the error code 04 on the display and battery symbol flashing. After Googling code 04, it showed 'throttle no homing'. Strange, as I have never had a throttle connected.

After some head scratching, I found the problem. As I haven't connected a throttle, I just leave the connector wrapped around the handlebars with the end dangling. A sneaky little drop of water had got into the connector head and was shorting the pins. This was confusing the Bafang and causing the error code.

View attachment 20136

A lesson learnt the hard way

A fraction of the time fault codes can throw you off slightly, but down to your good observation and persistence you were able to narrow down the main cause. good on you and thanks for sharing.

MS.