Battery drain

[Andrewb83]

Hey im having trouble with the charging system in my 72 5.7l c10. Basically something in my truck is draining the battery. I put a new battery in twice and both times the battery is dead within 24 hrs. Is far as I know there are no accessories such as lights, and there is no radio. I' be got new battery cables and everything looks ok, but I'm think it coul be the alternator. When I went to take off the alternator I realized I have 2 belts but no idea how to get them off, there isn't the standard pulley that you put 1/4" wrench into and it frees up the belt. Thank again for the help

Andrew
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[Andrewb83]

Tensioner pulley there's no tensioner pulley...couldn't think of the word at the the moment
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[motornut]

In 72, you were the tensioner lol

350 Alt?most have long bolt under it,through a long sleeve
might be one on the back,
but a slider/ajuster is the one on the front of the top bracket

Alt cases and brackets vary and case backs can be turned if needed

[Andrewb83]

Oo lord this will be a fun FIRST then. Thanks
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[Andrewb83]

Got the alternator checked it fine. Anybody have any other ideas why could be draining the battery. I heard the starter could be the problem. Guess ill check that out hit any other ideas would be swell.
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[hwyix]

See how much draw your truck is pulling down with the engine off and key out of the car. ( 50ma ish is normal, new cars (clocks, alarms, memory savers, draw a little more current. see below for typical draws )

While doing the current draw test:

Pull one fuse at a time wait 30 seconds ish and see if the multimeter changes.
If so, your current draw is on that circuit. If there is still a draw and it stops
when you disconnect the alternator there is a very good chance that a diode is bad.


I did some tests on my 1994 rx7 (no stereo, no clock, no alarm) to see what normal was. I thought you might find this use full when tracking down your draw.

50ma key off (doors closed, nothing on,etc...)
450ma key off one dome light on
830ma key off two dome lights on
4460ma key on (everything off)
4810ma key on / one dome light on
14430ma key on / brake light
10300ma key off / brake light
20640ma key off / high beam
17390ma key off / low beam
15500ma key on / heater blower on high
7900ma key on / window all the way and still holding the button in the up postion

[utee05]

How did your troubleshooting go? I am running into a similar issue with my battery draining. Alternator works fine and I just replaced my starter so it will be fun to try and trace back to where the drain is.

[devinder8788]

i had the same problem with my 86 the battery always died took it to my mechanic he changed the belt that went to my Alternator and never had the problem again been bout 5 months

[utee05]

That is a good tip. Check the belts. I know I swapped out my belts cause the ones on mine were pretty bad.