BBS 01B 350w won’t turn on while unplugged.

Hi all, I have searched the forum and haven’t seen anything related to this- after charging the battery, I unplug the charger and press the start button, the screen stays blank as if there is no power. If I plug the charger in and press the start button, it starts up as normal showing 100% battery power but the screen goes blank and system shuts down as soon as I unplug the battery charger. The unit is 3 years old and is my daily commute 32kms round trip. I have contacted the supplier, whose only answer is to take it off the bike and ship it to them for testing which will be quite expensive and time consuming. Could it be the controller? Any input really appreciated. Thanks, Pete.
I have contacted the supplier

My first guess is the BMS has developed a problem. Check the input voltage and output voltage of the BMS, both with the charger plugged in and the charger not plugged in. You didn't say anything about the battery/BMS system so the first question is whether or not you even have access to test these voltages, etc.

agreed; the battery is most likley either not charging at all, or if it has a bms, it has shutdown it's output to protect the pack from overdischarge due to cells that are too low in voltage.

if it is not charging it could be for the same reason--cells that have dropped so low in voltage that the bms has turned off charging to prevent a potential fire due to damaged cells.

in the first case (bms shutdown output), sometimes just leaving it on the charger at least overnight, sometimes for days, may fix this enough to allow you to at least turn on the bike.


but if there is a battery problem, you'll need to post some pics so we can help you figure out how to open the battery to begin diagnostics; you'll need a voltmeter when you get that far.


another separate possiblity is that if the charging input is directly connected to the controller, and the battery inptut and output are also connected there, the battery could simply be disconnected from the system, either at it's main plug or internally (blown fuse, etc).

it is more likely that the charger plugs into the battery case, and the wires inside go to the bms input, which then passes thru electronics to the output, which then passes to the discharge connector of the battery, which goes to the controller/rest of bike. if it's done this way (the most likely way), then it implies all the connections and fuses are fine.

Thank you, I have no way of testing it but I do have a spare. Cheers

Thanks amberwolf and rassy, I appreciate your input very much. You have given me a lot to think about.
From memory, the battery had a life expectancy of 1000 charges, it would be getting very close to that. If individual cells are starting to fail, it may be time for a new battery.
I can’t complain, the bike paid for itself in 6 months with just the savings I made from not having to pay for parking at work.
I don’t have much experience with electronics but will ask around locally and see if I can find someone that can do the tests that you suggested. Thanks again!