Any reason that would make the battery drop from 12.5 to 12.2 in two days? I'll take the battery back to auto parts store and see what they say.
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HELP. Battery question
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Originally posted by jdvorwe View PostAny reason that would make the battery drop from 12.5 to 12.2 in two days? I'll take the battery back to auto parts store and see what they say.The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL
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Originally posted by jlevie View PostExcessive current draw when the car is off, or a bad battery.
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The current drawn from the battery when the car is off is referred to as the parasitic load. It will normally be in the range of 30-60ma. Improperly installed aftermarket electronics are the most common cause of excessive parasitic draw, but faults in the few circuits that are powered when the car is off is possible.
To check for excessive parasitic draw one disconnects the battery ground cable, uses a jumper cable from the ground cable to the battery to power up the car, connects the meter set for current measurement between the ground post and ground cable, and then removes the jumper for the current measurement. The jumper cable prevents the meter from seeing the starting surge as the car powers up. With all doors and the trunk closed if the current draw is more than it should be, remove one fuse at a time to find the offending circuit. Then trouble shoot that circuit. In most cases you will find the fault that way, but there are a few things that aren't fused, like the alternator.
A fuse that is blowing indicates that the circuit powered by that fuse is drawing too much current.
When chasing electrical problems the wiring diagrams for the car are a big help. See http://wedophones.com/BMWManualsLead.htmThe car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL
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Originally posted by jdvorwe View PostI just thought of something, I have actually been disconnecting the battery when not using the car or testing it. Would that make any difference?The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, AL
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