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Recliner[_3_] · December 9th 16, 04:20 PM posted to uk.transport.london

On Fri, 9 Dec 2016 14:30:45 +0000 (UTC), d wrote:

On Fri, 09 Dec 2016 13:57:45 +0000
Recliner wrote:
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

Wonder what the roof thing is then. Its pretty large , way too large to be
an aircon unit. Perhaps its braking resistors for when the regen braking can't
cope?

Yes quite likely. Could also be the aircon or cooling radiators for
the batteries, which are likely to get quite hot. There might be more
of a clue if you can see one from above; for example, you can see the
hydrogen cylinders in the open-top box on the roof of the
hydrogen-powered buses.

They're not as quiet as I expected; obviously there's no engine noise,
but the transmission has a loud gear whine.

Thats probably the noise of the motors themselves I would imagine. There's
probably little if any transmission to speak of.

There's a reduction gearbox, which probably makes more noise than the
motor(s). There may also be some sort of prop shaft and differential.