My e-bike stopped working yesterday, and I am not able to tur the display on. Measuring voltage on the battery cables I get 0V. One theory is that the controller is bad leading to a short circuit. Disconnecting the battery and measuring on the cables to the engine/controller I am getting 0,3 ohm, does that make sense?
Problems with Bafang motor - what should the resistance be?
- Thread starter Dessmo
- Start date
The standard failures are MOSFET in the controller and hall sensor in the motor. There are standard tests for these, needing only a multimeter.
Troubleshooting - Learn
One of the things about meshing complex electrical and mechanical systems together is that occasionally things can go wrong! We've seen more than our fair share of ebike issues come and go over the years - from shot ball bearings, seized freewheels and stripped threads to defective hall sensors...
Try those tests. Then you need a proper voltage from the battery. If you get 0V an internal fuse may have blown.
If one is seeing 0v then it is a battery issue, the internal fuse has blown hence 0V reading.
Pic of battery please ?
If one looks carefully one may find a grommet port hiding a fuse holder on the exterior of the battery , if so then a fuse is excessible . If not the battery will have to be opened to access the fuse holder.
Pic of battery please ?
If one looks carefully one may find a grommet port hiding a fuse holder on the exterior of the battery , if so then a fuse is excessible . If not the battery will have to be opened to access the fuse holder.
Thanks, I will look into that.The standard failures are MOSFET in the controller and hall sensor in the motor. There are standard tests for these, needing only a multimeter.
Troubleshooting - Learn
One of the things about meshing complex electrical and mechanical systems together is that occasionally things can go wrong! We've seen more than our fair share of ebike issues come and go over the years - from shot ball bearings, seized freewheels and stripped threads to defective hall sensors...ebikes.ca
Try those tests. Then you need a proper voltage from the battery. If you get 0V an internal fuse may have blown.
Thanks, the battery is brand new. The strange this is that I can measure 42V on the battery, but as soon as I connect it to the motor it falls to zero. So I think there is a short circuit in the controller or somewhere else in the motor.
The display works independently and will switch on as long as it's receiving battery voltage, so if it doesn't switch on, it's not receiving battery voltage.
If your battery switches off as soon as you connect to the controller, you most likely have blown MOSFETs in the controller. You can confirm that by rotating the motor backwards, where you'd get high resististance to turning, or you can measure the resistance between each motor phase wire and the battery positive on the controller with everything disconnected from the controller, then repeat with the three readings to the battery negative wire. each group of three should be the same as each other and in the range 3k to 24k - often around 7k.
Thanks a lot, can you replace the MOFSET or do you have to replace the whole controller.
You check mechanical resistance to turning, not electrical resistance. Just turn the wheel backwards and feel how difficult it is to turn. With a blown MOSFET, you have to push hard.
Don't think about solutions until you know the cause.