Hi folks. My motor is single phase brushed rated @250watt/24volts, battery is 36v/4ah, and motor controller is 20amps. I'm considering adding a supercapacitor bank with about a 5000mah capacity and 40 volts (4v, 1100F per capacitor) in parallel with the battery. Next, I want to use the controller as a braking system by reversing polarity to/from it and send its back EMF into the capacitor bank. After inspection, I learned that the positive terminals on the controller are bonded; so, I only need to switch the negatives with a simple DPDT switch. I then am thinking I could adjust the motor controller's duty cycle with the accelerator just like a brake lever and apply it to decelerate at a desired amount. I suspect a DCDC voltage regulator might be required to ensure healthy voltage charge from the Back EMF, but maybe not?

Is this a realistic plan on how to apply regenerative braking with the controller; or, am I only going to blow it up.

Anyways, I'm very new to all this. All I have is a B.S. in EE and only familiar with power/construction/etc.

Thanks...

 

I'll need to figure out a way to keep the capacitor empty by not allowing the battery to discharge into it...

 

Some MOSFETs can be used to steer current where you want it to go.

A comparison of battery-charger topologies for portable applications, By Alvaro Aguilar https://www.ti.com/lit/an/slyt769/s...55831&ref_url=https%3A%2F%2Fwww.google.com%2F

 

If the controller does not presently provide a braking function, adding it will be a "big deal". So instead use a relay to switch the motor power to the capacitor bank when you operate the brakes. That will provide adequate isolation. Using that power recovered from braking might just include a diode between the battery pack and tghe capacitor bank, or, to be more efficient, a switching "boost inverter" to charge the battery from the capacitor bank to recover a lot more power.

 

I also encourage you to follow Mr Bill’s suggestion.

 

The big challenge with regenerative braking is during HARD braking, where for a short time the motor is over-driven and producing much more power than i was designed for. A battery can not accept charge like that, but up to some level a capacitor bank can accept charge much faster. Then, with a step-up/step-down switcher it can deliver that charge to the battery at a rate that it can accept. But creating such a supply is quite a challenge, because it needs to operate over a very wide input voltage range so that it can recover most of the charge from the capacitor bank. So it will probably be more than a $50 markup above the purchase price.