5kw 150a

[Keith LaFetra]

My bike vibrates a bit at low speed after riding hard like 5 mins. Anyone know why this would be? When it cools off it gets nice and smooth again

 

[E-HP]

Absent any details about your controller or motor, seems like it would be temperature related. Wild guess, it's due to high motor temperature affecting the hall sensors.

 

[Keith LaFetra]

Absent any details about your controller or motor, seems like it would be temperature related. Wild guess, it's due to high motor temperature affecting the hall sensors.

I don't know too much. 150 amp sabvaton and 5kw nb power. Motor. Running 59 ah all together with 3 separate 72v molicell batteries.

 

[E-HP]

I don't know too much. 150 amp sabvaton and 5kw nb power. Motor. Running 59 ah all together with 3 separate 72v molicell batteries.

When it happens, stop and feel the motor and controller to see if either are hot. The Sabvoton 72150 has over-temperature protection, so maybe that's kicking in.

 

[Keith LaFetra]

When it happens, stop and feel the motor and controller to see if either are hot. The Sabvoton 72150 has over-temperature protection, so maybe that's kicking in.

I'll check that out today. I changed dc current from 100 to 150 and it seems a little better. Is that possible?

 

[amberwolf]

DC Current is probably Battery current. Increasing that increases the power available to the controller, which will increase overheating problems if that's what is causing it.

The normal cause of vibrations is a motor/controller timing problem, which is usually caused by hall sensor signal problems.

They can overheat and begin failing to switch correctly; it's common enough. The way to fix this is to not overheat them, either by lowering power usage to the point where the motor can shed heat at least as fast as it is generating it, modifying the motor for better cooling (lots of threads about various ways to do that) or changing the system's properties (wheel size or motor winding (kV)) to match the actual speed vs power usage. (For instance, if you are spinning a motor slower than it's full speed while also using full power means it's wasting a lot of that power as heat inside it).

If it is resolved by increasing battery current available to the controller, then I don't know what is causing it, other than some strange controller firmware design. :/

 

[Keith LaFetra]

DC Current is probably Battery current. Increasing that increases the power available to the controller, which will increase overheating problems if that's what is causing it.

The normal cause of vibrations is a motor/controller timing problem, which is usually caused by hall sensor signal problems.

They can overheat and begin failing to switch correctly; it's common enough. The way to fix this is to not overheat them, either by lowering power usage to the point where the motor can shed heat at least as fast as it is generating it, modifying the motor for better cooling (lots of threads about various ways to do that) or changing the system's properties (wheel size or motor winding (kV)) to match the actual speed vs power usage. (For instance, if you are spinning a motor slower than it's full speed while also using full power means it's wasting a lot of that power as heat inside it).

If it is resolved by increasing battery current available to the controller, then I don't know what is causing it, other than some strange controller firmware design. :/

Thanks so much for explaining that! I did change the wheel size down to 16 and I believe that's whe. It started but that seems to be the closest to speed accuracy. I'm going to try messing with that a bit. Thanks for taking the time to explain that to me!