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Old 12-22-2010, 05:55 PM
Ronbo Ronbo is offline
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Battery voltage changes very little between a charged and discharged state. DMM and electronic gauges have very high input impeadances (around 10M ohms) at this resistance your multimeter is putting a load of 1.2uA (1.2 millionths of an amp). After a battery is charged it takes a little time for the electrolyte to "settle down" to a "at rest" voltage of around 12.5V, a discharged battery with, say, 10% capacity (A/hrs) will still read around 12V or more.

This is why 40yrs ago when the cost of a few feet of wire was not a factor on actually seeing what the charging system was doing, cars had ampmeters. The dash lights (or headlights) will tell you what the volts are.

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