What is causing my Kelly to regen?

[veloman]

I'm using an older KDHA brushed Kelly controller on my emoto. I have all the settings for regen on OFF. Yet, when the bike is moving and I roll back on the hall throttle, I get regen. This is really annoying, especially at stop signs.

The issue is that the controller seems to interpret a throttle voltage as regen when the speed of the bike is higher than the corrosponding throttle voltage.

So let's say I am riding a steady speed of 20mph. I release the throttle, then when I roll the throttle back on, at say 10 or 15mph (or any speed above 2mph) the controller does regen at a very partial throttle position. I can actually hold the throttle there and the regen will stay on until I come to a stop. But normally I want to accelerate and so after coasting, I roll on the throttle, get regen deceleration for a split second, and then I accelerate as the throttle is applied further.

Any ideas how to stop this from happening? I've been changing the settings in the controller, but nothing stops it. Maybe a resistor on the voltage line of the throttle?

 

[Willow]

If you roll back the throttle to 10% say, after coming back from a higher speed, it will want to set the speed of the motor back to 10% - which will in effect make the motor regen until it reaches that point. I don't think you can stop this from happening, you just have to get used to it...

 

[veloman]

I've never experienced anything like this on all my builds, some included brush motors too. On my BLDC hub motors running a throttle speed that is less than the motor speed just means less wattage goes into the motor (as if it's doing no-load).

 

[Alan B]

This probably comes from synchronous control of the FETs, it would not happen if a diode were being used for the recirculating current, but for higher efficiency they use a FET which effectively enables "slip regen". I would think they would have code to recognize this reverse current flow and shut down the FETs, perhaps there is a feature you can enable to do this.

A diode to prevent energy from going back to the battery might stop it, but the resulting unloaded voltage may rise to a dangerous level and cause a failure.

 

[veloman]

A few months ago I asked them for help on this and they refused, saying they don't support older models.

 

[veloman]

Has anyone had this problem on a Kelly brushed controller? I have a smaller new controller I put on my wife's scooter, and that operates smooth as ever.