In article ,
Theo wrote:
"Dave Plowman (News)" wrote:
You'd need an awfully large charger to get voltage spikes past the very
low impedance of a car battery.

If the battery is knackered, won't that impedance increase? As an
endpoint, imagine if the battery was completely dry - it's open circuit
and so wouldn't accept any current at all, and all the current would be
put into the car electronics.

Would sulphation raise the impedance?

Yes to both. But then that is two faults. An incredibly crappy charger and
a totally knackered battery.

Properly designed car electronics should have voltage regulators (and
components) rated up to 40 volts.

Indeed. Although I wouldn't be surprised if some weren't as
tolerant as they should be (also that aftermarket radio you got from
China...)

The old chestnut that only China makes rubbish. ;-)

--
*I want it all and I want it delivered

Dave Plowman London SW
To e-mail, change noise into sound.