Electric braking on hub motor

[periaz]

Hi guys,

I would like to know if the electric braking is a feature of controller or motor.
I have a 6" hub motor (bought on Al......ss) but my controller doesn't have this feature so I would like to buy another that has it. Do you think my motor will be compatible ?

Thanks

 

[Alan B]

It is a feature of the controller, as long as the motor doesn't have a freewheel it should be able to do regen/ebraking.

 

[periaz]

Hi !
Thanks for your help Alan

 

[cycborg]

A 6" diameter hub is almost certainly geared with a freewheel. If so, it won't be able to do regenerative braking regardless of controller. If you could post a link or photos or markings or something else to help identify the motor, we might be able to tell for sure.

Or you could check it by feel - lift the wheel and turn it by hand. If it's noticeably easier to turn forward than backward, it has a freewheel. If you can't tell, then you could disconnect the motor from the controller, short-circuit two of the motor's phase leads (the larger wires), and try again.

 

[periaz]

Ok I will test on Friday because I'm not at home at the moment.
Indeed, I don't want regenerative braking, I just want electric breaking (on the controller brake(low) and brake(high).

Thanks for your help

 

[Alan B]

I sense further confusion here.

For electric braking to work the system energy recovered must go somewhere. Most controllers use regen to do electric braking, sending this energy back to the battery. At low speeds regen becomes ineffective and reverse power to the motor is required to generate significant braking. Only sinewave controllers are generally equipped to do this, most trapezoidal controllers just quit trying to do regen at low speeds.

It is possible to send the braking energy to a loss device like a resistor. I haven't seen this done in a bicycle controller.

However the point made earlier is critical, no electric braking or regen can occur unless the motor is devoid of mechanical one-way clutching or freewheeling. A small diameter motor is likely so equipped and unlikely to be capable of regenerative or braking.

Note also that the battery system must be able to absorb the energy at a high rate that is similar to the discharge rate. Batteries and BMS systems often aren't set up for these high regenerative charge rates.

So while electric braking and regen are functions of the controller there are many other factors that must be compatible as well for it to be effective.