Jim Gambony wrote:
> If you connect an ohm meter between the + terminal and the + battery
> cable, all you'll do is either burn out the fuse in the meter, or burn
> out the meter itself!
No, this is fully acceptable behaviour. Just don't
start the car!
The meter will have the ability to measure current up
to a level way above what any slow-leak-short will have. For
example, his .128A leak kills the battery in a week, and
my handheld meter here reads up to 25A. In other words
unless his slow leak kills the battery in a few minutes,
the meter is well within spec.
> With the engine/ignition/all accessories off, there should be no
> electrical draw on the battery. In that case, you would see an open
> circuit between the +battery cable and ground. An open circuit will
> register infinite resistance (ie, no current can flow!)
Well, the problem with this method is that you are
trying to find a leak in a circuit at a different voltage
than the operating voltage.
Many things, including light bulbs, semiconductors are not
linear. Note that semiconductors in this statement can be real
or virtual caused by strange corrosion chemistry.
While in the real world, it'll probably work, it's not
generally recommended troubleshooting behaviour. Imagine
if for example your voltage regulator was shorted and
adjusted wrong, or your solenoid was malfunctioning,
and so on. It might take 12V to cause something to happen
that makes it start to leak. Also very likely to be
true if it turns out to be an internal fault in
an electronic radio.
--
Trevor Boicey
Ottawa, Canada
tboicey@brit.ca
http://www.brit.ca/~tboicey/
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