# How can I install a regenerative brake that operates separately from the controller??



## MechEngineerMike (Mar 31, 2013)

How can I install a regenerative brake on my EV that operates separately from the drive controller?

I converted a motorcycle into an EV and used a motor controller that is not capable of regenerative braking. What i'm looking for is off the shelf products that I can wire it to bypass the controller and charge the batteries at a controlled voltage. 

I've got a pretty good idea on the theory of using the motor as a generator, but I cant find components rated for the power (~20A+ at low speeds) that will be generated. I was thinking I could wire my left hand brake to a contactor that disconnects the controller from the motor. Another contactor would then connect the motor to a voltage regulator (output to 54V for my 48V pack, or 13.5V for each battery). The regen circuit would have a large diode to prevent the batteries from powering the motor at low speeds. With this setup, the regen would automatically deactivate at speeds too low to generate 54V, and the current wouldn't be too high if i didn't activate the system at high speeds. 
Im good at integrating electronic devices but not designing them from scratch. Like i said, i want to make this with mostly off the shelf stuff. Certainly somebody somewhere has done this before... Any ideas?

system specs
(4) 80 Ahr AGM batteries
8 kW PMDC motor, handles 200 Amps continuous.


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