leakage current in 12 volt alternator system

55 50 Ron · Oct 28, 2012

I measured 3.5 milliamps battery drain on the Farmall 400 gas 12 volt system with alternator that I just finished the new wire harness install. Engine not running and everything off. Is that acceptable? I haven't done any searching to see where that current is going.

Ron

rhtx55 · Oct 28, 2012

Check the current draw at the hot terminal on the alternator with the key off.

Bob M · Oct 28, 2012

3.5 ma leakage through the alternator when shut down is not much. To put it into perspective, the standby current drain for current production automobiles is typically 10 - 20 ma.

I would not be concerned.

Janicholson · Oct 28, 2012

I agree with Bob, at 150ma I would worry. Jim

Brownie 450 · Oct 29, 2012

As RHTX says--check the main terminal draw, then each of the other terminals also. You can isolate where the draw is.
If it's in one of the small terminals [1 or 2], the regulator is probably needing replaced.

realolman · Oct 29, 2012

(quoted from post at 16:49:52 10/28/12) I measured 3.5 milliamps battery drain on the Farmall 400 gas 12 volt system with alternator that I just finished the new wire harness install. Engine not running and everything off. Is that acceptable? I haven't done any searching to see where that current is going.

Ron

I have a feeling that if you can measure 3.5 mA , you can probably figure out what ever needs figuring out :wink:

Berth 29 opinions · Oct 30, 2012

With that small amount, it could just be a normal parasitic draw from the alternator or some other component. You can locate it by unplugging or disconnecting parts.
When working on Pontiacs, we could measure a normal parasitic draw with a meter, but would not light a 12 volt test light.

leakage current in 12 volt alternator system

55 50 Ron

Well-known Member

rhtx55

Member

Bob M

Well-known Member

Janicholson

Well-known Member

Brownie 450

Member

realolman

Member

Berth 29 opinions

Member

Similar threads