Regenerative Brakes for Cars

Especialy Bikes and other Alternative Cars

Some existing energy present in a moving vehicle can be stored when slowing or stopping and used again to accelerate. The storage system needs to be able to accommodate large amounts of energy in a short time and should not add excessive additional weight.

In an electric car or electric assisted bike, the motor and battery can be turned to some degree of regenerative use with the addition of some simple switches and or electronics. Most batteries can not accept large amounts of energy over a short time, so this is best for gentle braking during long slow descents. Electrical generation and battery storage are also not terribly efficient. ~40% at best.

Mechanical systems can be very efficient and can potentially accept large amounts of energy almost instantly. The issue here is added weight. Flywheels, springs, and pressure vessels are all heavy and possibly dangerous. It may be possible to use part of the frame as a spring or the lifted weight of the rider to avoid this drawback.

See also:

• http://www.ihpva.org/HParchive/PDF/31-v9n3-1991.pdf "In Search of the Massless Flywheel by John S. Allen
• http://www.halfbakery.com/idea/Regenerative_20Brake_20Bike Discussion, links.
• http://patft.uspto.gov/... US Patent #4,744,577 Mechanical Power Storage
• http://www.bionx.ca/en/advantages.html Electric bike with regenerative brakes.
• http://ecl.web.psi.ch/Publications/cap_pub/koetzcarlen.pdf Principles and applications of electrochemical capacitors

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