Need info and insight on 5th wheel regen braking

[DrivenByNothing]

Ok, so I'm fed up with getting out of class at 5:45 pm and creeping in traffic. I said I wasn't going to touch the Saturn and that's kinda still true. However, I want to add an auxiliary system that uses regenerative braking. The system must be removable if need be as well as be cheap and simple to construct and maintain.

Here's a simple idea I came up with:

(created with anim8or b/c it's quick and easy)

The idea above consists of using a lever to raise/lower the motor when needed (ie decelerating toward traffic).

I sent this to Paul (trebuchet) and he immediately replied with www.99mpg.com

I'm don't know nearly as much about this stuff as I'd like to and I'm hoping you guys can help. First, I know that a simple motor in reverse can generate power. This is what I'm banking on because it would make this whole thing nice and compact.

-Is there a specific breed of motor that does this? I figure I can just switch the terminals rather than the direction of rotation. That can probably be done via relays/solenoids.

-How much horsepower/torque should the motor be rated for if I'm only going to be using it to creep in traffic (maybe get up to speed at a later date, but I assume that will cost more $$)?

-How about capacitors instead of batteries? Is the technology there and the cost low enough for this to make sense?

-What are some of the benefits of using batteries/capacitors?

Any other suggestions?

Thanks,
Matt

[JanGeo]

You need a 2 quadrant controller for drive and regen and a PM brush motor with a lot of gear reduction to drive the wheel and either a big bank of ultracaps which hold about 5% of what a simular battery will hold or a big cheep lead battery or two or three. If you gear it for about 10mph max speed then you will have enough torque to move the car slowly when stuck in traffic

[kamesama980]

both caps and batterries :-p

caps are good for short term oomf, batteries provide a little longer go and hold charge a lot onger.

[FritzR]

How about a flywheel battery. Might want to wait a couple of years for the price to go down

http://www.ntu.edu.sg/home5/PG01898441/flywheel.htm

[JanGeo]

Caps are going to cost thousands of dollars - a few cheep Car batteries about $30 each. The controller is going to be the limiting factor for current surge and you probably will not need full power all the time or for long unless climbing a hill and then you will run out of battery power pretty quick anyway as well as overheat the motor so better to use it on level ground. Battery cycle limits will quickly be reached if used under heavy conditions - that is what the ICE is for - you want to be using the electric drive when you don't need a lot of power which is when the ICE is a waste of fuel to keep it running. A couple of hundred amps short term maybe 100 continuous would be what a small motor can handle. Any motor bigger will be heavy to very heavy and require more power with higher voltages and more expensive controllers. A simple setup would be to run on 12 or 24 volts with contactors direct to a motor without variable speed to the electric motor and when regen is needed like going down a hill traveling at a slightly higher speed will generate higher motor voltage feeding back to the battery and simply charge it, with the voltage regulated with a little brake use to control car/tire speed.