Shall we move on?

Agreed.

Thanks for the explanation about the early variable speed drives It was some time ago.

Some of the earlier AC postings read rather like the work of a young disciple, hence my attitude. Now I seem to have roused the master himself.

I've deliberately refrained from expressing an opinion either side of the IC / electric debate. I don't know enough. However, to paraphrase an earlier post.

I'm not anti green, I'm anti spin.

I set out to nail the vaguely inferred >90% overall efficiency figure, and I probably got as close as I'm going to get. IMO people are becoming confused and apathetic about the current mixture of science, hype, spin and FUD they are being deluged with from all sides. It doesn't help the cause when apparent men of science lose credibility in their own community by indulging unnecessarily in the more political arts listed.

I'll now happily bow out of this as you suggest.

(Graduated London 1964. First assignments were heat & mass balances on high temperature rotary kilns fired with finely divided coal. I really have been around for a very long time!)

Are you really a chemical engineer?

Considered using variable speeds once but had to abandon the idea. Safety regulations - the motor casings got too hot!!! (Somebody explain the implications of that to AC please)

Stop trying to side step the issue. Electric motors can be very efficient. However, the motor is only one part of the total system in an electric car and the overall efficiency is very much lees than 90%. Nearer 60% as stated

I've probably done more energy / mass balances in the real world than AC can possibly conceive of. A good place to start learning is rule one, which AC is either ignoring or has never learned :-

First define your system boundaries.

In this case the boundary is the car, not the electric motor, and the start point is the AC wall outlet as stated earlier in 'Everything's 90%'.

whereas the electric motor is not far off 100% efficient

If this thread achieves nothing else this glib statement must be debunked in the context of electric cars.

The usual electric motor is static and runs on stabilised mains power. It runs essentially at constant speed under constant known load and can be designed to be extremely efficient.

The car however must rectify the AC power source then store it. The DC output must then be converted back to a very special form of AC suitable for automotive (speed controlled) use. Only now do we get to the 'electric motor'. This is far from the standard unit described above and must operate under widely varying speed and torque conditions. It might have a 'sweet spot' and, if the design engineers are ever allowed to release the true efficiency of their composite systems, this is what will be quoted. Away from this optimum design region efficiency must fall off rapidly.

To recap:

Standard electric motors - very efficient - better than 90%

Electric cars - complex series of processes running under difficult conditions - probably less than 60% overall.