In article ,
Roger Hayter wrote:
The only thing I would add is that it is possible to get a false
negative in test 1. The alternator can be producing a significant
charging current, sufficient to raise the voltage under test conditions,
but still unable to produce sufficient current to maintain battery
charge in ordinary driving. Especially in the dark or in Winter. To be
sure you need to actually measure how much current the altenator can
produce at highish revs, most easily with a DC clamp meter.

Or simply switch on all the normal loads like headlamps and heater etc and
check the voltage again. With the engine at a fast idle. If the alternator
can't balance the load the voltage will be low too.

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*Real men don't waste their hormones growing hair

Dave Plowman London SW
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