The back of the envelope claims that a 1000 lb. vehicle with a constant
deceleration of .01 g (essentially rolling resistance at 10 mph on level
ground displaces ~200 Watts.

>  500km driving range with 4 standard car accumulators (12V)...In series..=
..

So a bit over 4 AH draw, for 30 hours...

Given new 100 AH "standard car accumulators" it's not possible. And that's
at 16 Km/Hr, under perfect conditions, with a 100% efficient motor.

Real "standard car accumulators" are quickly ruined by deep discharge,
but maybe your friend is getting a good deal on them... :)

Note that my assumptions are pretty optimistic - Your friends' car, loaded =
as
specified, is surely heavier, has much higher rolling resistance, & operate=
s in
uneven terrain at higher speeds than 16 Km/Hr.

Seems unlikely. Sorry about the gringo units.

 Jack
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