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Recliner[_3_] · December 9th 16, 03:15 PM posted to uk.transport.london

On Fri, 9 Dec 2016 16:06:54 +0000, Basil Jet
wrote:

On 2016\12\09 13:57, Recliner wrote:
On Thu, 8 Dec 2016 14:42:44 +0000 (UTC), d wrote:

I noticed some brand new (66 plate) single decker pure electric buses around
Waterloo today. They look very nice (apart from the huge battery pack on the
roof) and certainly have a good turn of acceleration off the line. I notice
however that their unladed weight is 12 tons which is more than a lot of
double deckers, presumably because of the battery. I wonder how efficient that
actually makes them when you calculate it all the way back to the power
station?

I suspect that the box on the roof isn't the heavy battery pack. The
whole back half of the bus has a high floor, and given the absence of
a diesel engine, I think that's where the batteries live. It means
that there are only a couple of step-free seats; the others are all in
the high back end.

They presumably have regenerative braking, so the weight won't make
too much difference to the efficiency. But it explains why there won't
be any double-deck battery buses.

This can't be right! Pushing a bus that's twice as heavy through the
streets has to use twice the energy, and regen braking won't change that
equation.

The energy cost is mainly to accelerate the bus, and much of that is
recovered with regen brakes. The rolling resistance is not only
relatively small, but these inner city buses don't spend much time
coasting along.