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Old 07-31-2008, 12:20 PM   #1 (permalink)
Efficiency freak
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Join Date: Mar 2008
Location: Berlin, Germany
Posts: 58

Frugolf - '96 VW Golf wagon
90 day: 40.36 mpg (US)
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Do-it-yourself regenerative braking?

Often I just can't avoid hitting the brakes and coming to a stop. To make significant progress on my fuel economy I'd like to look into regenerative braking.

Regardless of energy storage method, how do you get the power from and to the pavement?
Mike's E-wheel at Is it too late? - MIMA Honda Insight Modified Integrated Motor Assist Tour De Sol is technically beautiful and seems to work well, but it's quite complicated.

It's hard to attach drive components to the sprung components (tires, wheels, driveshafts). Seems as if one needs to tap into the transmission or starter gear or something, where you can firmly attach the regenerative components to the engine. But on the engine side won't work if you're EOCing and braking.

How about a second alternator somehow connected to the regular alternator belt and charging an auxiliary deep-cycle battery? Don't know if the belt is up to the job, though, especially when using the energy. (I know, why not go completely electric?)

How about a compressed air bottle as the storage medium, powered by an air motor that is either open (regular driving), pumping into the bottle (braking) or being driven by the compressed air (accelerating). Basically, hook a small Craftsman air compressor to the alternator belt or something. Many trucks etc. use air starters (but they've got the pneumatics on board anyway for the air brakes). But again, both of the above systems can't charge (regenerate) when the engine is off.

The system starts charging when the brake light switch is on and starts discharging either when you press the gas, or, only as a "start rolling and bump start from a stop" assist when you press the gas and the engine is not running.

What ideas do you guys have?


You ever notice that birds pulse & glide, too?
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