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Drain on the battery

adamforsythe

adamforsythe

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You know you have a bad draw on a battery when one of the best mechanics in the area is having trouble finding it. how many circuits in a truck can drain a battery over night? I just went over to the garage and disconnected my accessory circuit. It can't be any of the fused links right?????? Wouldn't that end up just blowing fuses?
Thanks
Adam
 
adamforsythe said:
You know you have a bad draw on a battery when one of the best mechanics in the area is having trouble finding it. how many circuits in a truck can drain a battery over night? I just went over to the garage and disconnected my accessory circuit. It can't be any of the fused links right?????? Wouldn't that end up just blowing fuses?
Thanks
Adam
Click to expand...
i had that problem when my diode blew in my alternater.but it also left my dummy lights on in the dash.so it was easily found.
 
Nope not the alt.....it charges the battery up just fine....it's only 2 years old to with less then 2,000 miles on it.
Thanks
Adam

chulisohombre said:
i had that problem when my diode blew in my alternater.but it also left my dummy lights on in the dash.so it was easily found.
Click to expand...
 
I have a drain I need to fix too...
I replaced my alt and didnt fix it....

they say disconnect battery negative...
put volt meter on amps...and put 1 lead on battery and 1 lead on neg cable...
check amperage... I dont know what it is supposed to be under.. but low...
then start pulling fuses until it goes down.. then you found the circuit....

I need to do this...:crazy:
 
just a thought has he done the whole hook up a test light to the battery and start pulling fuses to find the draw? and also is your motor carb'd cause if so if its elec choke and you didnt wire the choke properly that draws a 12volt constant that will drain your battery over night easily it happend to my buds truck just a thought..
 
Better find a new mechanic! Heavy drains are one of the easiest electrical faults to find. As said, the alt can drain when the motor is switched off even though it charges fine when running. Just rig up a volt or amp meter as Rootbreaker says and disconnect fuses, then components until the drain drops off. Do one at a time and if no difference, replace it and try the next.
 
I'm going to pick my truck up today or Monday and I'll take a look at it.
Thanks
Adam
 
25ma has been the magic # for many years. If your battery goes in 8-10 hours that should be easy to find. Disconnect - battery cable as stated above. Use a fused jumper to verify the draw won't kill the meter fuse. 10 amp fuse with my fluke. If you blow a fuse do not hook up the meter. Use a test lamp installed between the battery and - cable. When pulling fuses don't forget the circuit breakes as well.

This way you protect your tools.:D
 
25ma is the magic number. I just went through the same problem. I had a draw on my system, but mine wouldnt really show up til the truck sat for 2 weeks. I had new optimas. AFter much research the process to find the draw was easy. It was outlined in this thread already. In my case I was getting a draw of 75ma, jus enuff to kill the battery over long period.

LIke posted:

1) Disco the neg. terminal from battery

2) Put volt meter red wire on neg. battery cable

3) Put volt meter black wire on neg battery terminal

4) Put volt meter settings on AMPs. Look at numbers

5) Start pulling fuses.

When you pull a fuse and the amps drop, there is your draw. Now keep in mind if your under the dash and you have dome lights, you need to pull this fuse first. cuz you dont want anything ON while your doing this, the slightest about of current will put a draw on the system and itll make it harder to find.

What was my cause? It ended up being an Autometer TACH. I had it wired into a HOT circuit and somehow it was drawing power. I was surprised it was that. But I moved that wire over to a KEYED circuit and never had an issues since.

GOOD LUCK>
 
Something's wrong with your procedure BadMix:confused: If you pull the negative lead off the battery you break the circuit and won't have any drain. You have to have a complete circuit.

There is a doughnut type clamp that will meter amps of a wire passed through it which will work if you are not sure about running the draw through your meter.
 
Nothing wrong with my procedure. Your using the VOLT meter to complete the circuit. You are putting the volt meter between the disconnected neg. battery cable and the neg. battery terminal.
 
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I agree with the above techniques (good auto electric shops typically use the test light option). I would add two things:

1) A relay could be the problem. If you disconnect the - battery terminal, a stuck relay will become open again and you will not detect the draw. To avoid this, attach your test light's alligator clip to the battery cable and put the probe on the center of the battery post (assuming you have top post terminals). Remove the cable end, being careful not to touch the cable end on the probe. If the light is lit, there is a draw. By hooking the test light up this way, the circuit is never broken and will not "release" a stuck relay. If you have side posts, you can still do this procedure by probing the negative terminal under the side-mount cable end.

2) I have seen the best auto electricians fail to find a draw yet confirm that the battery drains over night. After replacing the battery, the problem no longer existed. Further research confirmed that the battery, although it passed load tests, was indeed internally shorted and would lose its charge in a short time.
 
I agree on both accounts. Ive never had any luck with the test light method. that is more OLE SKOOL. :D

First thing I did was check my battery when I had my issue. I thought i could be a bad cell, the auto shop did a lil more than jus a load test, they charged it completely and then put a load on it and then wanted to see what kind of recovery it had, etc. In my case it was the tach, not the battery. But I can see where the batt. could give false readings.
 
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