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DannoXYZ DannoXYZ is offline
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Join Date: Feb 2003
Location: SF East Bay
Posts: 1,856
Quote:
Originally Posted by Jfrahm View Post
The alternator can also cause a drain if some of the diodes are bad. Does anyone know what the acceptable current draw from the alternator (key off) is?

-Joel.
i guess it comes down to how often you drive car and battery's capacity. I've seen figures from 55 to 73-ah, so let's take 64-ah as a ballpark figure. And assuming you drive the car at least once a week. And we don't want to drain the battery more than halfway. Let's do some math:

7-days = 168 hrs
max-drain = 32 ah

Max drain-rate = 32 ah / 168 h = 0.190 amps flow

So you can measure up to 190 mA of flow in order not to drain battery halfway in a week. I usually measure about 20-50mA flow at rest on car with no problems. I'm not exactly sure on that halfway mark, i'm sure if battery is in good condition, you can have it drained more than that and it'll still start car.
Old 01-21-2017, 04:47 PM
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