Steve,
Well, maybe Theo's analogy was a wee bit of a hyperbole Steve, but your
explanation doesn't wash either. First off, I also had a problem with my
ammeter overheating; it was just the connections on the back weren't tight,
so a little bit of resistance causes a lot of heat when you're drawing 20-30
amperes. Let's say there's one ohm of resistance - that's 400-900 watts!!
Obviously, even 1/10 ohm is a problem. But, any resistance in the ammeter
just reduces the current from the alternator, so the connector there should
get cooler if anything. That is, unless there's heat conducted from the
ammeter back through the wire to the alternator terminal. This doesn't sound
likely. What might better explain what happened is the heat caused the
ammeter to short to ground, and of course that would cause the alternator
output wire to heat up. Then when you bypass the ammeter, the short goes
away and the problem is solved. Now, this may seem like an academic issue
insofar as either way, it's the ammeter that's the culprit. But for guys
like Theo that try to solve problems logically, there's a big difference. By
the way, an ammeter is just a voltmeter hooked across a very small resistor.
The resistor is the 'big wire' and the voltmeter is the 'little wire', so
very little current is really going through the little wire. Also, with the
ammeter removed, your lights, air conditioner, etc. should work a lot better
since there's less voltage drop across the ammeter.
I completely agree with substituting a voltmeter for the ammeter because
it's more informative to know what the voltage of the system is under
various conditions. It should normally be about 14.3V with the engine
running and the battery fully charged. If it drops below about 13V, for
example, it means your battery is probably going bad.
Bob
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