Battery problem

Check for voltage draw: Get a multimeter, set it on amps, unhook negative battery cable, put one lead on negative cable and the other on the negative battery terminal. If you have more than 50 milliamps you have a parasitic draw. Once that is determined, start pulling fuses until the number drops AND that is your problem circuit.

+1 on the dirty battery thing. I have seen a brand new battery on a rack have a drain across the top on a really humid day.

I use a volt meter between the neg battery post and the neg. cable.

This allows you to see a draw that is smaller than the current needed to light a test light.

When you pull the fuses one at a time to find the drain watch the meter as you put the fuses back in ONE AT A TIME.

If there are 2 or more circuits at fault this will help find them.

If a fuse is reinstalled and it shows a draw, note it and pull it back out and resume adding fuses until done.

I've had a vehicle that three different circuits were all drawing the battery down at the same time. It took 3 forevers and a week for me to figure it out!

Caman96 said:

That’s why I bought my own(load tester). I always felt like what are they gonna say at the parts store “no, we don’t need to sell you a new battery”. No offense to anyone here who works at one, it’s just I don’t know them!

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Yeah, I've considered buying one, but just haven't yet since it would not get used often.

454cid said:

Yeah, I've considered buying one, but just haven't yet since it would not get used often.

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Yeah I bought one and probably won’t use it much. It’s here if you need it!

Last year my battery would die within about 3 days. I did the voltmeter test and never saw over .040A draw.

Got tired over screwing within dead batteries and this was my solution:

Harbor Freight 4A battery tender with a 7 Pin trailer connector. This time of year the truck might sit for months at a time. I keep it plugged in, and no more dead batteries.

454cid said:

How did you avoid all the dinosaurs???

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AVOID the dinosaurs? They were the bulk of our business.

GM B and C bodies, Full-size Ford/Mercury/Lincoln, Full-size Mopars...without them, we'd have starved. God bless the dinosaurs. Even when the dinosaurs dowsized in '77, they were still pretty chunky compared to Euro vehicles with similar interior volume.

454cid said:

I've accidentally checked AC voltage because my Fluke defaults to AC, and sometimes I forget about it. What would you call excessive for AC voltage? I can't recall a number off hand.

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Oh, great. Now I gotta research. My primary electrical system tester has a red LED labeled "Ripple", that glows when it's excessive.

Wild-asp guess until I can figure out the real answer: 1/4 volt AC.

[Edit]
www.picoauto.com/library/automotive-guided-tests/alternator-ac-ripple-diode-test/

https://www.picoauto.com/library/automotive-guided-tests/alternator-ac-ripple-diode-test/

This source says 500 millivolts/ 1/2 volt AC.

I dunno. 1/2 volt AC seems like a lot to me.[/Edit]

JSlezak83 said:

Last year my battery would die within about 3 days. I did the voltmeter test and never saw over .040A draw.

Got tired over screwing within dead batteries and this was my solution:

Harbor Freight 4A battery tender with a 7 Pin trailer connector. This time of year the truck might sit for months at a time. I keep it plugged in, and no more dead batteries.

Click to expand...

Be VERY careful. This is not a good solution for two reasons:
1. Cheap Communist Chinese battery chargers can fail and set fire to your car, garage, etc.
2. Having a battery that goes dead all the time, and constantly needs to be charged is hard on the battery, and hard on the alternator. Wouldn't surprise me to find that your battery has sulfated from this use; and it's almost guaranteed that you're using-up the water supply with all the charging. IF (big IF) you can access the electrolyte reservoirs, you might wanna check them for being low.

You need to have the battery load-tested. It may be that it just won't hold a charge and should be replaced.

Schurkey said:

Oh, great. Now I gotta research. My primary electrical system tester has a red LED labeled "Ripple", that glows when it's excessive.

Wild-asp guess until I can figure out the real answer: 1/4 volt AC.

[Edit]
www.picoauto.com/library/automotive-guided-tests/alternator-ac-ripple-diode-test/

https://www.picoauto.com/library/automotive-guided-tests/alternator-ac-ripple-diode-test/

This source says 500 millivolts/ 1/2 volt AC.

I dunno. 1/2 volt AC seems like a lot to me.[/Edit]

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Thanks, I'll check my truck tomorrow... maybe the Saturn too.

Schurkey said:

Be VERY careful. This is not a good solution for two reasons:
1. Cheap Communist Chinese battery chargers can fail and set fire to your car, garage, etc.
2. Having a battery that goes dead all the time, and constantly needs to be charged is hard on the battery, and hard on the alternator. Wouldn't surprise me to find that your battery has sulfated from this use; and it's almost guaranteed that you're using-up the water supply with all the charging. IF (big IF) you can access the electrolyte reservoirs, you might wanna check them for being low.

You need to have the battery load-tested. It may be that it just won't hold a charge and should be replaced.

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If he has a legit tender, I wouldn't #2 would be an issue. Your reasoning is precisely why I'm not using my old Sears charger as much anymore.

Regarding #1, even my NOCO is made in China, I think....unless it was Vietnam.

CHECK ALL GROUNDS, AND RELOCATE THE ONES IN QUESTIONABLE PLACES.. Like the main battery ground that goes to an aluminum bracket..!!!! move it to the block or the head. Use solid copper, THICK diameter battery cables.

thers also a ground on the inside top of the passenger fenderwell. they can corrode or strip out. I welded a hardeneded bolt over the stripped out hole that the bolt originally went thru and put a larger stainless steel bolt in it and tightened it well. Theres another ground on the chassis near the back bumper. checkl and clean them all. if u still cant find the draw you can get a DC ampmeter and hook it to the battery. read the ampdraw. then start pulling fuses, one at a time, rechecking amp draw. once u find the fuse that controls the draw, you can get a wiring diagram, and run it down.

texas tough said:

CHECK ALL GROUNDS, AND RELOCATE THE ONES IN QUESTIONABLE PLACES.. Like the main battery ground that goes to an aluminum bracket..!!!! move it to the block or the head. Use solid copper, THICK diameter battery cables.

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Aluminum isn't a bad conductor if it's big enough, and a casting should be big enough. I mean, they make wire out of it. You don't find iron wire. I'd be more concerned with it being clean, and coated with some sort of protectant. Maybe use copper anti-seize on the bolt threads.

I agree, It would be a good idea to check all the grounds, as you suggest.