"John Rumm" wrote in message
o.uk...
On 17/10/2012 13:56, The Natural Philosopher wrote:
Dave Plowman (News) wrote:
In article ,
tony sayer wrote:
But 80% of the energy in that tank is wasted. So go back and do some
sums.

Why don't you give us some realistic realisable sums instead?..

Dribble do sums? He thinks a battery car 100% efficient. Bit like his
brain...

In actual fact a battery car with regeneration added in is sort of
about 100% compared to a fuel car without which is probably in the
25%-35% range.

He's a bit out, but not by much.

Even with regen, you are going to lose heat from the motor, and each time
you convert to and from chemical energy for battery storage (there is
where a capacitor for collecting regen would be better).

Supercapacitors take in electrical energy and give it back out as electrical
energy with no state change. 98% efficient. R&D to a combination battery
and Supercaps is underway.

However its worth mentioning that most cars peak braking power tends to
exceed their motive power by several times. Hence the motors won't have
the power to capture all the regen energy on heavy braking, and you will
need to rely on the normal brakes thus wasting that energy.

Magnetic brakes work well on aircraft. Hybrids rarely have their pads
changed as they rarely are used.