On Feb 14, 10:11*am, Karl Townsend
wrote:
It should be no more than 14.2 volts. * If it is than that is the reason
the battery is failing.

John, it is below that, I have a voltmeter on my dash.

I wouldn't trust an in-dash voltmeter to be that accurate.

ditto. if you haven't got 14.2 to 14.4 at a decent rpm, your charging
system has a problem. That would kill battery life.

I recently diagnosed the charging system on my car. The
manuals and such (I have a few) weren't much help
beyond what-wire-connects-where, but there were some
very odd indications.

You can charge a battery, give it a known discharge,
and see if it is holding enough energy. My battery was OK.

You can monitor the charge voltage to see if the normal
operation causes the correct charging voltages (in the
13 to 14.5 range). This, was inconsistent. Tightening
wires and replacing one cable seemed to fix it.

But almost nothing else; there was no easy way to
test the generator ex-situ, or any clear indications
what the voltage regulator was doing except as part
of the full assembly of components.

So, there was no clear determination of what to replace.
The generator came with a helpful little pamphlet that
said 'replace the voltage regulator at the same time',
and it's a common recommendation to replace the
battery after any charging problems. So, I'm thinking
a 'professional' would replace battery, regulator, generator
all at the same time. Whether they need it or not.
Without ever diagnosing to the individual faulty part.

That's just bad engineering.

My problem was an intermittent short inside the generator,
which clobbered the battery charge four times in
the space of a year (but usually worked when the
meter was attached).