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Old November 27th 03, 07:33 PM
Jim Adney
 
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On Wed, 26 Nov 2003 01:03:11 -0500 "Bruce W...1"
wrote:

Now two weeks later I check the battery. Its voltage is 12.7V. The
charger circuit measures 13.7V. And I measured the drain, from the
alarm and radio, it is 10mA.


That means that there is 100 Ohms between the PS and the battery. It's
likely that this is the resistance of the meter that you used to
measure the 10mA, and that the actual current without the current
meter was more.

But I still don't understand how you could read 13.7V at the PS and
12.7V at the battery unless there is a significant resistance between
the two. Note that this resistance could be in the ground leg, too.

OTOH, holding the battery voltage at 12.7 will be just fine for long
term storage. Higher voltages will keep it topped up at full charge,
but they also do some long term damage and convert water to hydrogen
and oxygen via hydrolysis.

You're really better off at the lower voltage, and 12.7V is just fine.

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Jim Adney
Madison, WI 53711 USA
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