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Old 12-24-2015, 03:50 PM   #8 (permalink)
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Originally Posted by jjackstone View Post
Have you done any testing to show how much energy or additional range the regen provides? Always interested in that type of information. Also, other than the potentiometer and additional wiring needed, are there any other components necessary to control the amount of regen available?

I am running a Curtis 1238 controller, which is very programmable. I can program it to regen at any percentage of the full 650 amps, which allows me to use a lot more regen than with off throttle applications. Typically, off throttle regen is set around 10% of full potential, so the other 90% of available waste energy gets wasted on friction brakes. All I have is the "thumb pot" and two more wires going to the controller to allow using regen for my primary braking system.

As far as additional range, I see little advantage when driving 55mph on flat ground, since I am playing by the same rules of nature as a manufactured EV does, but the more hilly an area is and the more braking is needed, the more profound the efficiency compared to what off throttle would be. The efficiency improvement comes from two things. The first is having the vehicle maintaining a less disturbed motion", by having the vehicle "freewheel" like a ten speed bicycle or DC drive system, and this is what prevents a largely unrecognized loss of efficiency. The second thing that improves overall efficiency is harvesting every last drop of waste braking energy, which comes from never using friction brakes for anything other than holding the vehicle at traffic signals.

I still do lots of testing, and my conclusion is that off throttle regen is as useless as putting a wind turbine on the roof, or alternators on the wheels. It is possible to drive an off throttle configuration in a way that might get a small return if the driving conditions are right, but at the cost of electricity, the negligible returns would not be worth the trouble. To make any substantial use of regen, the kinetic benefits of a DC system have to be there to separate "waste" energy from "wasted"energy, and then regen needs to be used to harvest every last drop of the now isolated "waste" energy.
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