Mastuna wrote:
But heavier after.

It depends on the car.

But even in the worst case scenario, if the battery car ends up 300 kg
heavier than the ICE car (that's 20%), it still consumes less energy
than the ICE car because its thermodynamic efficiency is so much
higher.

Even if the electricity used to charge a battery car were 100% derived
from oil power plants, it would still use less oil per km than an
equivalent ICE car. Modern combined-cycle thermal power plants are 60%
efficient. Electricity transmission is 95% efficient. Charging/
uncharging about 80% and the electric motor about 95%. And don't
forget that reforming crude oil into petrol takes a lot of energy too,
while power plants are able to burn the heavier oil fractions
directly.

which plays havoc with the unsprung weight, giving considerably worse
ride and handling, and requiring heavier duty suspension.

That's a good point. Do you know how much an in-wheel motor wheel on
the Mitsubishi Colt weighs compared to a normal wheel? Would be an
interesting figure to obtain. Each motor is rated at 20 kW. I guess
that's why Mitsubishi only put them on the rear wheels where the
handling is less affected.

I am not sure how much of a difference unsprung weight really makes. I
have driven the same car, an Audi A3, with alloy wheels and steel
wheels and I haven't noticed any difference whatsoever. Made me think
that perhaps alloy wheels are just a marketing scam. Or maybe I didn't
drive it fast enough ;-)

It makes a great deal of difference in a racing or rally car, but its
not teh be all and end all of car performance. Ona smooth road it makes
almost NO difference. Anyway the motors in the wheels are very light,
scarceley more than the swing axle on a traditional design , and of
course the statement that it needs heavier duty suspension is more or
less ********: that is function of the car SPRUNG weight, by and large.



the transmission, the exhaust system and the cooling system, saving
even more weight. All this freed up weight and space can be taken up by
batteries.
...and then some...

Typical electric cars have 300-500 kg of batteries, even if they don't
weigh more than ICE cars overall.
If they have 300-500kg of batteries, before including the weight of the
motors and cabling, then they will inevitably weigh more than an
equivalent ICE cars, because an entire ICE drivetrain weighs less than
that.

They don't just replace the drivetrain. They replace most of the
engine assembly, the exhaust system, and the water cooling system.

the starter motor, the alternator, the regulator,the starter battery,
the fuel injection system, the distributor, the fuel pump, the oil
filters, the gearbox..its perfectly possible to get to - apart from
probably an electric cooling fan or two - only four moving parts - the
wheels/motors themselves. Plus a few suspension and steering joints.

...

Thirdly, electric cars have regenerative braking and don't suffer from
idling losses in city traffic, making them more efficient still.
Stop-Start in city traffic is hardly unusual in ICE cars.

True, hybrids do negate that advantage.

Indeed. And the chemistry of those batteries, in manufacture and
disposal, is sooooo environmentally friendly.

That's a difficult comparison to make, because both ICE cars and
battery cars are recycled very efficiently these days. Batteries
contain valuable metals, so it is unlikely that they will simply be
thrown away at the end of their life cycle. Not unlike catalytic
coverters. Are the toxic emissions (dicounting CO2) from manufacturing
500 kg of Li-ion batteries worse than the emissions from burning
10,000 L of petrol in an ICE? Hard to tell.

Anyhow, I think that the main advantages of battery cars will be
economic, not environmental, once batteries are mass produced at high
volume and low price. If the current downward trend in battery prices
continues, they may well replace the ICE.

They almost certainly will. Like nuclear power stations, they are teh
only technology sufficiently mature and economical to have a hope of
doing the job.