[Lab] regenerative braking

[Richard Guy Briggs]

On Wed, Sep 14, 2011 at 05:59:59PM -0400, Sam Roesch wrote:
> >
> > > The reason I dont' think it will work is that it's based on bad
> > > driving in the first place.
> > I do agree strongly with you here.
> 
> While I agree that it might be based on bad driving habits, and that it
> would be more efficient for people to drive better- it doesn't subtract from
> that fact that many people do have bad driving habits. Thus the technology
> may be appropriate for retail to the general public.

Many battery technologies are unhappy about very fast charging and will
probably dump power to avoid being charged too fast if you are braking
hard while regenerative braking.  Alternately, it could charge something
else to temporarily store that power, but something that can take a
faster charge is likely to be less efficient in storing and retrieving
that charge.  Again, it comes down to driver habits to avoid wasting
energy.

Then again, why do so many people haul around 20 times their weight to
propell themselves?  Why not use an electric assist velomobile that is
half their weight?  Add regenerative braking to that.

> On Wed, Sep 14, 2011 at 10:46 AM, Richard Guy Briggs <rgb at tricolour.net>wrote:
> > On Mon, Sep 12, 2011 at 05:06:23PM -0400, Darcy Whyte wrote:
> > > I'm figuring that it will only work in some strange circumstances for
> > cars
> > > (like if you live on a mountain).
> > >
> > > http://incandescent.ca/a-case-for-regenerative-braking/
> > >
> > > What do you think?
> >
> > It has some potential.  Solar cars in the North American rayces use
> > regenerative braking in their systems since there are enough starts,
> > stops, hills and speed limits that make it worthwhile.  The Australian
> > rayce doesn't need it since there is one traffic light in the 3000 km
> > course route between Darwin and Adelaide, in Alice Springs, and there
> > are very few hills of any note, so the regenerative braking parts are
> > extra weight and complexity that work against the efficiency of a solar
> > car.
> >
> > > The reason I dont' think it will work is that it's based on bad
> > > driving in the first place.
> >
> > I do agree strongly with you here.
> >
> > > For instance when I see a red light (or anticipate it), I get off the
> > > gas and start coasting. I arrive at the light just when it's green. So
> > > I never piled on the gas to get to the red light, then hit the break,
> > > then had to get back up to speed. If you're driving properly in the
> > > first place you're not going to waste enough energy to recover.
> >
> > Danish transplant to Australia adventurer Hans Tholstrup did many tests
> > of this theory including circumnavigation of the continent of Australia
> > and managed to demonstrate that driver behaviour had a very significant
> > effect on energy economy and pollution.
> >
> > > To make it work for me, I'd have to intentionally accelerate towards a
> > > red light so I could then use the brakes.
> >
> > I mostly agree with you, but I do see some use.
> >
> > I recall an article in IEEE Spectrum about 20 years ago about an
> > electro-mechanical battery consisting of a carbon-fibre flywheel running
> > on magnetic bearings in a vacuum at a speed of several hundred thousand
> > RPM.  There were two clamped together to avoid gyroscopic effects.  The
> > reason for the carbon fibre and high rotational speed is to get the
> > energy density up with total mass down.  I probably still have the
> > article here somewhere...
> >
> >        slainte mhath, RGB

	slainte mhath, RGB

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