Roland Perry wrote:
In message -septembe
r.org, at 08:29:47 on Mon, 20 Jul 2015, Recliner remarked:
http://www.theguardian.com/politics/...ries-london-bu
ses-add-to-boris-johnsons-problems

This confirms the observation that the Boris buses seem to run noisily on
diesel most of the time.

It's a pity that the Grauniad has angled this as a political
Wolmar-for-mayor story, though: whatever Boris's faults, technical problems
with a battery pack can hardly be blamed on him. But I wonder why the Boris
bus batteries are seemingly more troublesome than those in other hybrid
buses?

I doubt it's the batteries themselves, but it's quite plausible the
charging/discharging electronics wasn't quite right and this could have
shortened the life of the batteries (both the life each day, and the number of days).

Or I wonder if the batteries/electronics overheat, like the passengers?
Everything is squashed into quite a small volume under the rear stairs, and
maybe the ventilation is inadequate.

Maybe they just had a faulty component, which is what the story suggests:
"The battery packs are being upgraded as soon as possible and within the
warranty period, at no cost to TfL or the taxpayer.”

I'm not sure what you mean by the battery "life each day," though. These
batteries are continually charged and discharged, almost at every stop.
They're not charged overnight and used all day. Even when they were
brand-new, the buses didn't run for more than about five minutes without
the noisy four-cylinder engine firing up. So the batteries are subjected to
hundreds of charge/discharge cycles very day, which can't be good for them.