[cockney steve]

The cynic in me says that every auto-factor in the country keeps L.A. batteries in stock. 50 years ago, I had an alarm-system on the company car. It was operated by a key-switch fitted to the external body-panels. There is no obvious reason (other than cost) why the dashboard "reset" could not be so- fitted.

[Jim Jones]

@Jim Jones there must be something possible more cleverly than having to lump a poxy 12V battery around. It is not as though that needs a lot of power anyway, no heavy diesel to crank.

A Li-ion battery would be better, smaller, lighter, agreed. Maybe even use solar to keep it topped up.

[skydriller]

Maybe even use solar to keep it topped up.

Thats Another thing I dont get... EVs have bonnets and roofs. Why do none of them have solar panels as a feature of the design??

[Rob P]

I understand that it is perfectly possible, but even at the height of summer they would only add a few miles to the available range so are hardly worth the expense and weight of fitting them.

Some brands do have the option of solar panels to recharge the 12v.

Rob P

[riverrock]

Because the amount of energy brought in by a solar panel able to fit on a car roof would be negligible compared to the energy contained in the traction batteries.

The electronics and transformer (up to 400V) in my Zoe are designed to be most efficient when getting 32A / 240V ( over 90% charging efficiency). At 10A/240V it's down to 70%. It uses more than 250W keeping its systems running and if battery cooling required, HVAC uses at least 1KW.
You might get 500W from a roof covering solar panel? So that would be 250W going into the battery ( assuming no cooling). So it would need 160hrs of sunlight to fill the battery - so what, 13 days with 12hrs of sunlight? Then the have the extra weight to carry along.

[stevelup]

That's because that particular system was engineered for that sweetspot.

You'd have a different inverter that was optimised for the input voltage from solar - no reason that couldn't be >90% efficient and I doubt the batteries would need active cooling at such low charge rates.

But the rest of your point remains - even with the whole roof covered, you're not going to get much.

[skydriller]

I only asked because I recall school projects involving solar powered vehicles. And that was 30years ago, so surely the tech must have evolved, yet we dont see solar panels on vehicles today.

[Flyin'Dutch']

I only asked because I recall school projects involving solar powered vehicles. And that was 30years ago, so surely the tech must have evolved, yet we dont see solar panels on vehicles today.

Those vehicles - IIRC were extremely flimsy and light and going at only just more than pedestrian pace.

[Colonel Panic]

IIRC the Audi A8 (back in 2008?) used to have solar panels above the sunshine roof which were enough to keep the cabin cool if nothing else. Seemed like a very sensible option to me.

[Paul_Sengupta]

[Flyin'Dutch']

Backt to our meteorology classes for the PPL, the earth is hit by about 2kW of solar energy per square meter.

That is why there are no cars with solar panels which extend range in a meaningful manner.

[eltonioni]

Backt to our meteorology classes for the PPL, the earth is hit by about 2kW of solar energy per square meter.

You remember that! Next you'll be telling us that you know all the different clouds.

[Flyin'Dutch']

At our gliding site we considered building a home thermal and did some calculations......

[Paul_Sengupta]

Backt to our meteorology classes for the PPL, the earth is hit by about 2kW of solar energy per square meter.

Is that at 52 North or whatever?

[TravellerBob]

When I complete this latest assignment my next car will be a Tesla.

That is all.