On Friday, 9 December 2016 21:08:01 UTC, Recliner wrote:
DRH wrote:
The Red Arrow BYD / Alexander-Dennis Enviro200EV buses have
iron-phosphate batteries at the rear and in the roof pod, which also
incorporates the aircon unit. The driveline comprises two 90kW wheel-hub
motors and water cooling system plus regenerative braking system.

There are also five BYD double-deck battery buses in (intermittent) use on route 98.

Thanks, that's interesting. Were the additional batteries in the roof pod
added to increase the range? They sound like an afterthought.

No, I think it is to balance the weight. They appear to be split 50/50 with the very back of the bus.

DRH

DRH wrote:
On Friday, 9 December 2016 21:08:01 UTC, Recliner wrote:
DRH wrote:
The Red Arrow BYD / Alexander-Dennis Enviro200EV buses have
iron-phosphate batteries at the rear and in the roof pod, which also
incorporates the aircon unit. The driveline comprises two 90kW wheel-hub
motors and water cooling system plus regenerative braking system.

There are also five BYD double-deck battery buses in (intermittent) use on route 98.

Thanks, that's interesting. Were the additional batteries in the roof pod
added to increase the range? They sound like an afterthought.

No, I think it is to balance the weight. They appear to be split 50/50
with the very back of the bus.

OK, that makes sense. They must put quite a lot of weight on what's
normally a flimsy body structure, though. Or do those buses have monocoque
bodies, with no chassis?

On 2016\12\10 08:21, DRH wrote:
On Friday, 9 December 2016 21:08:01 UTC, Recliner wrote:
DRH wrote:
The Red Arrow BYD / Alexander-Dennis Enviro200EV buses have
iron-phosphate batteries at the rear and in the roof pod, which also
incorporates the aircon unit. The driveline comprises two 90kW wheel-hub
motors and water cooling system plus regenerative braking system.

There are also five BYD double-deck battery buses in (intermittent) use on route 98.

Thanks, that's interesting. Were the additional batteries in the roof pod
added to increase the range? They sound like an afterthought.

No, I think it is to balance the weight. They appear to be split 50/50 with the very back of the bus.

Putting weight on the roof to improve the balance?

On Sat, 10 Dec 2016 11:55:48 +0000, Basil Jet
wrote:

On 2016\12\10 08:21, DRH wrote:
On Friday, 9 December 2016 21:08:01 UTC, Recliner wrote:
DRH wrote:
The Red Arrow BYD / Alexander-Dennis Enviro200EV buses have
iron-phosphate batteries at the rear and in the roof pod, which also
incorporates the aircon unit. The driveline comprises two 90kW wheel-hub
motors and water cooling system plus regenerative braking system.

There are also five BYD double-deck battery buses in (intermittent) use on route 98.

Thanks, that's interesting. Were the additional batteries in the roof pod
added to increase the range? They sound like an afterthought.

No, I think it is to balance the weight. They appear to be split 50/50 with the very back of the bus.

Putting weight on the roof to improve the balance?

Without that counterweight, there would be very little weight on the
front wheels.

On Saturday, 10 December 2016 09:37:35 UTC, Recliner wrote:
DRH wrote:
On Friday, 9 December 2016 21:08:01 UTC, Recliner wrote:
DRH wrote:
The Red Arrow BYD / Alexander-Dennis Enviro200EV buses have
iron-phosphate batteries at the rear and in the roof pod, which also
incorporates the aircon unit. The driveline comprises two 90kW wheel-hub
motors and water cooling system plus regenerative braking system.

There are also five BYD double-deck battery buses in (intermittent) use on route 98.

Thanks, that's interesting. Were the additional batteries in the roof pod
added to increase the range? They sound like an afterthought.

No, I think it is to balance the weight. They appear to be split 50/50
with the very back of the bus.

OK, that makes sense. They must put quite a lot of weight on what's
normally a flimsy body structure, though. Or do those buses have monocoque
bodies, with no chassis?

I think they have separate chassis and body. The two earlier BYD ("Build Your Dream") buses tried on the Red Arrow routes, EB1 and EB2, had bodies built by BYD itself. They had batteries in a pod on the roof and in two large cabinets over the front wheels. The new ones have a bog-standard Enviro 200MMC adapted diesel bus body, but possibly strengthened to cope with the extra weight of the batteries.

DRH

On 2016-12-10 12:30:58 +0000, Recliner said:

Without that counterweight, there would be very little weight on the
front wheels.

How, out of interest, does that differ from a normal rear-engined bus?

Neil
--
Neil Williams
Put my first name before the @ to reply.

Neil Williams wrote:
On 2016-12-10 12:30:58 +0000, Recliner said:

Without that counterweight, there would be very little weight on the
front wheels.

How, out of interest, does that differ from a normal rear-engined bus?

The batteries are several tonnes heavier than an engine+fuel tank.

On Fri, 9 Dec 2016 11:05:44 -0800 (PST)
DRH wrote:
The Red Arrow BYD / Alexander-Dennis Enviro200EV buses have iron-phosphate =
batteries at the rear and in the roof pod, which also incorporates the airc=
on unit. The driveline comprises two 90kW wheel-hub motors and water coolin=
g system plus regenerative braking system.

Wheel hub motors? They're a poor idea as they massively increase unsprung
weight. Also I'm surprised they could fit motors powerful enough in the wheels
with enough cooling for a bus tbh. Hope westminster has increased its pothole
budget.

--
Spud

On Sunday, 11 December 2016 22:53:24 UTC, Recliner wrote:
Neil Williams wrote:
On 2016-12-10 12:30:58 +0000, Recliner said:

Without that counterweight, there would be very little weight on the
front wheels.

How, out of interest, does that differ from a normal rear-engined bus?

The batteries are several tonnes heavier than an engine+fuel tank.

The 12m BYD/ADL Enviro 200EV's GVW is 18,600kg.
The near-equivalent 11.8m Enviro 200 diesel bus is 14,400kg.

Probably the bulk of the extra weight is batteries.

There are two other electric buses that were tried briefly on the Red Arrow routes and are now being transferred to route 108. These are Irizar i2e's which appear to have all the batteries in a full-length roof pod. They thus appear to be rather taller than normal single-deck buses, and have similarities to the hydrogen buses on route RV1.

Whereas the original BYDs had a pronounced but not unpleasant whine from the electric motors, the newer ones are quieter but the Irizars were very quiet indeed - an impressively smooth ride.

DRH

On Mon, 12 Dec 2016 09:39:45 +0000 (UTC), d wrote:

On Fri, 9 Dec 2016 11:05:44 -0800 (PST)
DRH wrote:
The Red Arrow BYD / Alexander-Dennis Enviro200EV buses have iron-phosphate =
batteries at the rear and in the roof pod, which also incorporates the airc=
on unit. The driveline comprises two 90kW wheel-hub motors and water coolin=
g system plus regenerative braking system.

Wheel hub motors? They're a poor idea as they massively increase unsprung
weight. Also I'm surprised they could fit motors powerful enough in the wheels
with enough cooling for a bus tbh. Hope westminster has increased its pothole
budget.

They do increase the unsprung weight, though they also save the weight
of the live axle, differential and half the prop shaft. Incidentally,
the units also include a reduction gearbox.

But these heavy buses plod along at low speeds in dense urban traffic,
so I don't think the unsprung weight will be nearly as serious a
problem as it would in a higher speed vehicle.