Electric buses
 

wrote:
On Thu, 16 Jul 2015 20:19:19 +0000 (UTC)
Recliner wrote:
Paul Corfield wrote:
I suspect that at some point there will have to be a London trial
which involves a pantograph based charging facility or facilities.
Several manufacturers offer that option so it would make sense to test
it even though there will be issues as to where you can install such
kit.

Is that a single wire tram-style pan, or two wires, trolley-bus style? If
one wire, how is the bus earthed while being charged?

Google siemens electric truck. It'll probably be a similar setup to that.

So, two pantographs?

Electric buses
 

wrote:
On Fri, 17 Jul 2015 07:38:29 +0000 (UTC)
Recliner wrote:
More relevant was the Rolls Royce Phantom which I quoted. Its batteries are
probably as big as a bus's.

I doubt it. On the youtube video of one of the BYD buses it says the
batteries weigh 3 tons.

Yup, the car battery was 'only' 2/3 of a tonne:

From
http://www.autocar.co.uk/car-review/...-phantom-102ex

The 71kWh battery pack is made up of a NCM
(Lithium-Nickel-Cobalt-Manganese-Oxide) pouch cells. There’s a total of 96
cells weighing 640kg, 90kg more than the combined weight of the
conventional engine and transmission.

Three separate 3kW charger units are fitted to the battery pack and it
takes 20 hours to recharge the huge battery. Using a three-phase electrical
supply it takes eight hours for a full charge.

The 102EX also features induction charging, using an induction pad mounted
under the floor. Positioning the car over a transmitter pad, installed in
the road surface allows the battery to be recharged across a gap of 150mm.

This giant battery pack drives a pair of electric motors, which are mounted
on the rear subframe, and housed inside water jackets, themselves chilled
by coolant piped down from the radiator.

The motors drive a single ratio transmission with an integrated
differential. Each motor is rated at 145kW but, more importantly, together
they also deliver a whopping 590lb ft of torque from standstill. Although
the power from the motors is 48kW down on the equivalent power from the
V12, the torque peak is 59lb ft, or 11 percent, up.

Electric buses
 

On 2015-07-17 07:25:44 +0000, Roland Perry said:

The problem is for the driver (getting wet).

Diddums. Might he shrink?

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

Electric buses
 

On 2015-07-17 08:26:24 +0000, y said:

Why hasn't Wrightbus come up with an offering? Seems to me they've been
caught napping over this.

They have, indeed they were first in the UK; the Milton Keynes ones are
Streetlite-derived. Though I think the electrical equipment is from
another company.

I guess the Chinese may have been cheaper?

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

Electric buses
 

Neil Williams wrote:
On 2015-07-17 08:26:24 +0000, y said:

Why hasn't Wrightbus come up with an offering? Seems to me they've been
caught napping over this.

They have, indeed they were first in the UK; the Milton Keynes ones are
Streetlite-derived. Though I think the electrical equipment is from another company.

Presumably that's the point? Wrightbus is a bus assembler, but the point
of these trials is to test electric power trains in the real world. It's
companies like Siemens who make those, not the companies that fabricate
bodies.


I guess the Chinese may have been cheaper?

Almost certainly. The Chinese are very keen on electric vehicles, given the
terrible smog levels in the major Chinese cities, and so will be mass
producing these buses.

Electric buses
 

In message
-septem
ber.org, at 08:40:18 on Fri, 17 Jul 2015, Recliner
remarked:

Three separate 3kW charger units are fitted to the battery pack and it
takes 20 hours to recharge the huge battery. Using a three-phase electrical
supply it takes eight hours for a full charge.

Hmm. 90 amps on three-phase. What people often forget is that the
National Grid is on record as saying that these kinds of additional
power draw are unsustainable for anything more than a fraction of
vehicles.

(And it's not just the main grid, but also the local supplies and
substations).
--
Roland Perry

Electric buses
 

On Fri, 17 Jul 2015 08:37:03 +0000 (UTC)
Recliner wrote:
wrote:
On Thu, 16 Jul 2015 20:19:19 +0000 (UTC)
Recliner wrote:
Paul Corfield wrote:
I suspect that at some point there will have to be a London trial
which involves a pantograph based charging facility or facilities.
Several manufacturers offer that option so it would make sense to test
it even though there will be issues as to where you can install such
kit.

Is that a single wire tram-style pan, or two wires, trolley-bus style? If
one wire, how is the bus earthed while being charged?

Google siemens electric truck. It'll probably be a similar setup to that.

So, two pantographs?

I can't think of another way unless they have some strap dangling down from
under the vehicle that contacts a metal pad.

--
Spud

Electric buses
 

On Fri, 17 Jul 2015 08:40:18 +0000 (UTC)
Recliner wrote:
The motors drive a single ratio transmission with an integrated
differential. Each motor is rated at 145kW but, more importantly, together
they also deliver a whopping 590lb ft of torque from standstill. Although
the power from the motors is 48kW down on the equivalent power from the
V12, the torque peak is 59lb ft, or 11 percent, up.

I don't know why the articles bother quoting torque since the amount of torque
that reaches the wheels - which is what matters - depends on the gearing ratios
as well as the motor.

--
Spud

Electric buses
 

On Fri, 17 Jul 2015 10:18:05 +0100, Roland Perry
wrote:

In message
-septem
ber.org, at 08:40:18 on Fri, 17 Jul 2015, Recliner
remarked:

Three separate 3kW charger units are fitted to the battery pack and it
takes 20 hours to recharge the huge battery. Using a three-phase electrical
supply it takes eight hours for a full charge.

Hmm. 90 amps on three-phase. What people often forget is that the
National Grid is on record as saying that these kinds of additional
power draw are unsustainable for anything more than a fraction of
vehicles.

(And it's not just the main grid, but also the local supplies and
substations).

Yes, it's scary. Imagine how much more current the bus charger will
draw. And then multiply it by the number of buses on the route,
several of which may be being charged simultaneously.

And then consider how small the grid's safety margin will be next
winter. And how much of that 'clean' power still comes from fossil
fuels...

Electric buses
 

On Fri, 17 Jul 2015 10:22:02 +0000 (UTC), y wrote:

On Fri, 17 Jul 2015 08:40:18 +0000 (UTC)
Recliner wrote:
The motors drive a single ratio transmission with an integrated
differential. Each motor is rated at 145kW but, more importantly, together
they also deliver a whopping 590lb ft of torque from standstill. Although
the power from the motors is 48kW down on the equivalent power from the
V12, the torque peak is 59lb ft, or 11 percent, up.

I don't know why the articles bother quoting torque since the amount of torque
that reaches the wheels - which is what matters - depends on the gearing ratios
as well as the motor.

The gearbox needs fewer ratio because of the high starting torque.
Most EVs only have a one or two-speed gear box.