My Bafang Ultra G510 Motor Is Burned Up (Fried)

[ArtieP]

I am wondering if this has happened to anyone else, and what may have gone wrong with my motor.
I purchased it from CNE Bikes in August of 2018, and It only has 629 miles on it. It just suddenly quit running toward the end of a 28 mile ride.
I am using a 52 volt battery pack on it. Do you think that is too many volts for this motor? I was assured that the motor will run fine with this battery pack. The controller is a 48volt controller.

Here are a few pictures:








I am also wondering about a connector that was not attached to the controller when I took the gear side cover Off. I could find nowhere on the controller that this connector could possibly attach to. It is the colored wires with the black connector attached to them. Does anyone know what this connector is for and what it does? Could this be the cause of the overheating problem I had?

The connector is pictured on the lower right side of these two pictures:




I bought two of these motors at the same time and I am using the other one for my wife's bike. It only has 320 miles on it. I rode hers for several miles, to see how hot it would get and I found that It did get fairly warm.

I know I can buy another new motor, but I am very hesitant to plunk down another $600.00 until I can find out what went wrong with this one, and find a solution for the overheating problem with this Bafang Ultra motor.
I really would appreciate it if anyone could help or give their opinion and advice for this problem.

 

[Voltron]

This is just guessing, don't know that exact motor, but that sure looks like a Hall wires connector, with the white wire probably being speed signal. I'm not sure the motor would even run without Halls working, does it fit any plugs on the controller, even though the board side might be white, and maybe came unplugged pulling the cover?

Edit--- I of course could be totally wrong, and it could be dual mode controller than still runs sensorless, and the white wire is a temp sensor not doing it's job, but would still need to plug in somewhere?

 

[Voltron]

Re the overheating, the voltage won't make the motor overheat, it's the total power i.e. high amps at that voltage. Have you been changing gears so the motor isn't subtly bogging down on hills and slowly cooking?

I ask as it's a powerful motor, and can keep grinding even though it would be happier at higher rpm, esp up a hill where loads are high but air cooling effect is low.

 

[ArtieP]

Thanks for your reply Voltron.
I checked very carefully to find a place to plug in that connector but there is none.
I am using a Rolhoff 14 speed IGH and I try to be careful not to bog down the motor. I usually always pedal the bike (I can use the exercise) trying to keep a steady, good speed cadence and I hardly ever use the throttle.

 

[FlyingFinn]

There is a good reason why that wire can’t be plugged anywhere. Previously Bafang made motors that had the hall sensor on rotor. Mid-production they changed to the current design where the hall sensor is a magnet in the end of the rotor shaft. That’s why they were left with an excess hall sensor and wires.

Apparently your motor doesn’t have a temperature sensor. Later models have features that prevent this from happening. For eg. my 2019 motor will start to reduce amps after a certain temperature. This has happened to me once and it may reduce the power as heavily that SPORT5 feels like ECO1. So clearly it works.

If you decide to fix it there is shops that will re-wire your magnets. Your motor is busted but not ruined.

 

[ArtieP]

Thanks FlyingFinn for your response. Can you tell me what shop or shops would be able to re wire the magnets?
It has occurred to me that my wife's motor probably has the same problem since I purchased them at the same time. I am going to remove it and find out.

 

[FlyingFinn]

Thanks FlyingFinn for your response. Can you tell me what shop or shops would be able to re wire the magnets?
It has occurred to me that my wife's motor probably has the same problem since I purchased them at the same time. I am going to remove it and find out.

I have no clue where you could find those shops other than that they do exist. ”Stator re-winding” to google and you may find a professional close to you.

You should tape/glue a small temp sensor in the left hand side outside cover of your motor and wire a small lcd screen showing the temps to your handlebar. These can be found from AliExpress as low as $1.