On Sat, 07 Jul 2007 21:20:34 GMT,
Olof Lagerkvist wrote:
wouldn't it be better to build a trolley-bus network with trolley buses
with regenerating brakes?

Regenerative braking depends on being able to guarantee that you can
dump the energy somewhere.

When you carry batteries with you it's not really a problem[1] - it's
reasonable to assume that your generator will maintain a good electrical
connection to the battery.

[1] Actually it is. Typically the batteries cannot take charge quickly
enough.

When you are connected to an external grid it is a bit of a problem (not
insurmountable, just difficult) because you can (and do) lose connection
from time to time. When you lose connection you also lose the brakes.

Super capacitors look promising for the future for regenerative braking
(regardless of what power source is used).

I'm wondering if we might start seeing something like this soon for
bicycles. I think that generator/motor plus supercapacitor ought to come
in at under 2kg[2] with the ability to store enough charge to stop (and
accelerate) a cyclist from 20-30mph to rest.

[2] not necessarily cheap, just possible.

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t,"
and there was light.

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