BBS01B not working - help

[PASJames]

My BBS01B (250 W 36V #1710090097) stopped working.
-Battery is charged and reads 41 volts at connectors between battery and mid drive unit.
-C965 display is blank-not working.
-Unplugged, inspected and carefully replugged all external connections
-On day the motor stopped working, I was riding normally and lost power and display. I noticed some moisture clouding beneath display glass that same morning which quickly dissipated. Bike never ridden or stored in rain and never sprayed down with a hose, but has been stored for a few months in a slightly damp shed in dry Southern California.
-Have not split motor unit to check connections there. Motor has less than 100 hours and has never been opened for service
-I bought and installed the kit new from China - no other owner.

Please suggest troubleshooting steps.

 

[amberwolf]

Is this a different one than a couple years ago?
https://endless-sphere.com/forums/viewtopic.php?f=28&t=92653&p=1355006#p1355006

If not, then though it's unlikely whatever originally caused the problem with the speed sensor power supply could've completely failed something else in thr controller. That wouldn't necessarily explain the display not turning on, though, as that is powered off the battery voltage itself that comes from the controller.


So, the question is, does teh battery read that 41v with everything still connected? Or is it only with the battery unplugged from the system (and reads lower, possibly near zero, when it is connected)?

If the former, then it's not likley the battery.

If the latter, the BMS of the battery has shut it's output off, and the voltage seen when not loaded is leakage.

 

[PASJames]

Thank you for responding. Yes. This is the same unit which I got help with on this forum when I had to abandon the faulty hall sensor and replace it
with a simple reed sensor. It has been working fine since that time.

The 41V from the battery was tested at the larger gauge red and white power input connectors between the battery and the motor. I did this while they were connected. Separately, I am getting no voltage readings at the 7 pin connector which exits the motor and feeds the display, brake disconnects, etc.

 

[amberwolf]

Separately, I am getting no voltage readings at the 7 pin connector which exits the motor and feeds the display, brake disconnects, etc.

Then that indicates taht most likely no power is getting from that battery input connection to the rest of the system.

The most likely thing is a wire broken off the controller side connector, past the point where the measurement was verified to be ok (41v).

 

[PASJames]

The bike has been very gently used. There is certainly no obvious pinching or scuffing of the power cable from the battery all the way to where it enters the motor unit. What is the possibility that the wire is loose or disconnected inside of the motor unit and before it enters the plastic seal pool of the controller? Are you saying that even if the controller is bad, I should still see voltage at the 7 pin connector going to the display?

 

[amberwolf]

I don't know about this specific controller, but most of them simply pass battery voltage thru to that connector, which then goes to the display, which then when turned on passes it back to the controller to turn it on.

If you get no voltage of any kind on any of the wires to the display, then something is preventing voltage from getting to the connector. That's probably a failure of connection between battery and controller.


Based on your testing so far, it sounds like the problem is on the controler side of the actual connector, if you're able to read voltage on the battery side. If you can't read any voltage on the controller side somewhere, then the problem is between where you can read the voltage and where you can't.


It could be corrrosion or some other issue in the connector itself, but most of the time electrical problems of any kind are in wires, or the connection points between the wires and the connector or the circuit board, if there is one.

 

[PASJames]

Thank you. I think I will open the motor case and check the controller wires and their connections next.

 

[PASJames]

amberwolf
Thank you for past assistance with this problem. I ordered a new controller and speed sensor from GreenBikeKit. It took four and one half months to arrive. After installing the new controller and sensor, carefully checking all connections and load testing the fully charged battery, it still did not work. Not wanting to wait forever for another shipment from China, I ordered a new C961 display from bafangusadirect.com which is located near me in Orange County, CA. the delivery took two days. I Installed it and everything works fine. It was probably the display all along. Note in my original post about the appearance of clouding/dampness inside the C965 display despite no exposure to water that I was aware of. I think I will split the case on the old display and try to find evidence of corrosion. Will report here if I find that.

 

[kcuf]

internet search

"dump bafang display"

all bbsxx users

should carry simple jumper

know how to use it