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From: paul@hpldola.HP.COM (Paul Bame)
Newsgroups: sci.electronics
Subject: Re: Electronic Car Brakes
Message-ID: <10960036@hpldola.HP.COM>
Date: 25 Sep 90 16:13:45 GMT
References: <8581@ncar.ucar.edu>
Organization: HP Elec. Design Div. -ColoSpgs
Lines: 32

> / hpldola:sci.electronics / stebbins@sisler.ucr.edu (john stebbins) / 10:12 pm  Sep 23, 1990 /
> In article <8581@ncar.ucar.edu>, cook@stout.atd.ucar.edu (Forrest Cook) writes:
> |> 
> |>>[lots of interesting stuff about electric cars and relative efficiencies]
[deleted]
> |> .
> |> How about electric car designs that brake by using the motor to charge back
> |> into the batteries?  Such a system could probably save several tens
> of percents
> |> in efficiency, especially for city drivers.
[deleted]

> There are a couple of problems you didn't address.  First is batteries
> charge slower by a factor of 10 or more than they discharge.  Second
> is that most people break much faster than they accelerate.  This compounds
> the first problem.  I haven't calculated the amount of energy that is 
> involved here so this may be absurd, but I was thinking that a whopping big 
> capacitor may take care of part of this problem and have the side 
> benifit of giving you more readily available energy for your next
> acceleration.  The phisical size of such a capacitor may be larger than
> the proposed vehicle for all I know.  Its just a thought.

> John Stebbins
> stebbins@ucrmath.ucr.edu
> ----------

Some experimental city busses use flywheel energy storage and supposedly
use regenerative braking to great advantage.  I can't remember references
but it seems like probably a Popular Science article several years ago.

			-Paul "Spice is the Variety of Life"
			paul@hpldola.hp.com	N0KCL