EV Discussion thread

Reed_Richards

I'm just saying that we would not want to live in single-glazed houses with thin metal walls which had no or minimal wall insulation.  In ICE cars insulation doesn't matter because they are heated with waste heat from the engine but in an EV it does. So don't they need to be better-insulated; much better than at present?  

QrizB

For an EV charged using SVT-priced electricity, it would make financial sense to heat it using one of those blown-air diesel combustion heaters. A litre of diesel contains about 10kWh of heat, so 15p a kWh or so. Might mess up your carbon footprint, though!

On a typical EV tariff, or even a good E7, electric heating will be cheaper.

Some EVs have heat pumps for heating. If these achieve a reasonable COP they'll be cheaper than diesel so long as you're not paying public charging prices.

EricMears

If reduced miles/kWh in cold weather really bothers you and you think the heating system is to blame then the answers pretty obvious : turn off heating, dress more warmly and use the heated seats to give a little more comfort.

Re the Rapid chargers costing more than petrol,  avoid them.  Hopefully bulk of charging will be done at home for under 10ppu so the occasional rapid charge won't affect your average cost/mile too much but that can be mitigated by using a charger for around 60ppu rather than an 85+ ppu network.  For those who have to charge away from home a lot,  take out subscription(s) to get a discounted rate.

Martyn1981

Reed_Richards said:

I'm just saying that we would not want to live in single-glazed houses with thin metal walls which had no or minimal wall insulation.  In ICE cars insulation doesn't matter because they are heated with waste heat from the engine but in an EV it does. So don't they need to be better-insulated; much better than at present?  

Maybe, especially if the insultaion helps with sound, since not having the drone and general NVH of an ICE, means that BEV occupants are more conscious of road/tyre and wind noise.

Some BEV's have laminated glass in the side windows, but again I think that's more for noise than heat insulation.

Also worth remembering that in the summer, a BEV is far more efficient at cooling, whether it has a heptpump or not. Since it's using the battery leccy, rather than generating its own, from the already inefficient ICE, which could lead to leccy generation efficiency of just 10-20%. You could of course open the windows, but I seem to recall that modern A/C is more efficient for fuel burn, than the aero impacts of windows - so a BEV with its own leccy, would certainly be more efficient using A/C than windows (speed dependent).

Reed_Richards

EricMears said:

If reduced miles/kWh in cold weather really bothers you and you think the heating system is to blame then the answers pretty obvious : turn off heating, dress more warmly and use the heated seats to give a little more comfort.

Just as, if the cost of heating your house in winter really bothers you then the answer is equally obvious, turn off heating, dress more warmly and use a heated throw to give a little more comfort.

What I'm saying is: "Why have dual standards for your house and for your car"?  

Martyn1981

Grumpy_chap said:

Martyn1981 said:

In this example, there are currently too many EV spaces (20%), which is upsetting ICE owners, and I can get that with parking limited. Spare spaces will encourage EV ownership, or at least reduce fears, so I guess it's a no-win situation, at the moment for LA's.

In our area, there are EV charge sockets being installed to lampposts.  Apparently, the Council is not able to designate the spaces as EV only, so these are available to all.  Most of the streets are back-to-back parked cars.  I have never seen anyone actually plugged into the lamppost chargers.

In other streets, there are fast chargers with the spaces designated as EV spaces.  The chargers seem to be out of order so no-one parks there at all whether EV or ICE.

I think that's where Trojan Energy may have one of the better ideas, by installing a charge point next to each space. Reduced cost, as the EV owner buys and stores the 'lance' which plugs into the pavement. No restrictions on parking, ICE, EV, or EV charging.

Hopefully, having charge points outside your house and nearby, will encourage locals, sitting on the fence, to make the leap to a PEV.

TROJAN ENERGY
SERVING COMMUNITIES, PRESERVING STREETS

QrizB

Martyn1981 said:

Also worth remembering that in the summer, a BEV is far more efficient at cooling, whether it has a heptpump or not. Since it's using the battery leccy, rather than generating its own, from the already inefficient ICE, which could lead to leccy generation efficiency of just 10-20%.

I might be misunderstanding you, but conventional ICE AC compressors are belt-driven from the ICE, so there's no additional electrical conversion involved.

So ICE > compressor not ICE > alternator > electric motor > compressor.

Grumpy_chap

Reed_Richards said:

I'm just saying that we would not want to live in single-glazed houses with thin metal walls which had no or minimal wall insulation.  In ICE cars insulation doesn't matter because they are heated with waste heat from the engine but in an EV it does. So don't they need to be better-insulated; much better than at present?  

I'm wondering.
Better insulation and double glazing would reduce the heating load.
The counter would be the energy to transport that extra weight.
I don't know which of the two would have greatest impact on miles / kWh.

QrizB

Grumpy_chap said:

Better insulation and double glazing would reduce the heating load.
The counter would be the energy to transport that extra weight.

Caravan windows are double glazed (plastic) and weigh less than single-glazed glass ones. (I see you can buy double glazed glass van windows, but with two layers of 4mm gass they're going to be heavier than single glazed ones.)

As for isulation, if we model a car cabin as being a cuboid 4m x 2m x 2m (big even for a SUV) it will have a surface area (including windows!) of 40 square metres. To cover that with 50mm of insulation will take 2 cubic metres of stuff. A typical insulation board is about 30kg/m3, so if you add 2m3 to the vehicle you're looking at adding 60kg.

Grumpy_chap

QrizB said:

Grumpy_chap said:

Better insulation and double glazing would reduce the heating load.
The counter would be the energy to transport that extra weight.

Caravan windows are double glazed (plastic) and weigh less than single-glazed glass ones. (I see you can buy double glazed glass van windows, but with two layers of 4mm gass they're going to be heavier than single glazed ones.)

As for isulation, if we model a car cabin as being a cuboid 4m x 2m x 2m (big even for a SUV) it will have a surface area (including windows!) of 40 square metres. To cover that with 50mm of insulation will take 2 cubic metres of stuff. A typical insulation board is about 30kg/m3, so if you add 2m3 to the vehicle you're looking at adding 60kg.

So, carrying an extra passenger all the time for the insulation.
I can't see plastic windows being favoured - not least for the way they would get scratched.