Battery drain
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New User
Joined: Nov 2002
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Battery drain
This may not be the correct forum but a question anyway. Are there any common problems that would drain the batterys? When the truck sits for more than two days the truck will not start without a jump.
When testing with test light inline on the negative side, the fuse that controls the under hood light, dome light, map light and glove box light seem to cause a decrease when pulled. I completely disconnected the under hood light with no change. Are there any more refined testing methods on FTE?
When testing with test light inline on the negative side, the fuse that controls the under hood light, dome light, map light and glove box light seem to cause a decrease when pulled. I completely disconnected the under hood light with no change. Are there any more refined testing methods on FTE?
Cargo Master
Joined: Jun 2003
Posts: 3,292
Likes: 6
From: Ardenvoir, Washington
You can try an digital ohm meter between the "disconnected" battery cable (plus side) and the ground side of the battery. should have no reading with the key off, if normal.. If you have a reading, example like 5 ohms, start pulling each fuse until the meter goes no reading .. Pull the plus side cable of the 2nd battery while you are testing..Also pull the hood bulb..
But, first before pulling batteries cables, I would check your voltage at a idle at the batteries.. should be around 14.4 volt if your alternator is working properly..
Another test i would do also is to check both batteries with a hydrometer to see if any battery cells are bad.. Napa sell one for around $20.. easy to use..
But, first before pulling batteries cables, I would check your voltage at a idle at the batteries.. should be around 14.4 volt if your alternator is working properly..
Another test i would do also is to check both batteries with a hydrometer to see if any battery cells are bad.. Napa sell one for around $20.. easy to use..
Cargo Master
Joined: Jun 2003
Posts: 3,292
Likes: 6
From: Ardenvoir, Washington
I suppose you could use a amp meter also.. but checking the resistance of the circuit will also show you if something is working that should Not be, with the key off..
Example: If you leave the hood buld in place, you will get a 2.4 ohm reading.. Pull it and the meter has no reading.. by using the method I described in Post #2..
Example: If you leave the hood buld in place, you will get a 2.4 ohm reading.. Pull it and the meter has no reading.. by using the method I described in Post #2..
Lead Driver
Joined: Jun 2003
Posts: 8,298
Likes: 24
From: Damon (South East Texas)
This may not be the correct forum but a question anyway. Are there any common problems that would drain the batterys? When the truck sits for more than two days the truck will not start without a jump.
When testing with test light inline on the negative side, the fuse that controls the under hood light, dome light, map light and glove box light seem to cause a decrease when pulled. I completely disconnected the under hood light with no change. Are there any more refined testing methods on FTE?
When testing with test light inline on the negative side, the fuse that controls the under hood light, dome light, map light and glove box light seem to cause a decrease when pulled. I completely disconnected the under hood light with no change. Are there any more refined testing methods on FTE?
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New User
Joined: Nov 2002
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Thanks to all that have replied so far. I was just out doing some more checking. I had the digital ampmeter hooked inline with the negatives disconnected and was getting a reading of .017milamps. I pulled the #15 fuse under the dash and the reading went to zero. 15 is the GEM, PCM, ABS module and brake shift interlock speed control. Now I am really stuck! Anyone no where to go from here? Please don't say dealer. Thank you all for the help so far.
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Freshman User
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I am by far no electrician but I believe the #15 fuse under the dash should be pulling some current, one of them is I cant remember right off hand which one. I would say alternator is your problem, mine did the same thing. It would charge fine but as soon as you turned it off it would drain the batteries. The guy at DB electrical told me they got a bad batch of regulators and that was causing my problem.
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Lead Driver
Joined: Jun 2003
Posts: 8,298
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From: Damon (South East Texas)
I am by far no electrician but I believe the #15 fuse under the dash should be pulling some current, one of them is I cant remember right off hand which one. I would say alternator is your problem, mine did the same thing. It would charge fine but as soon as you turned it off it would drain the batteries. The guy at DB electrical told me they got a bad batch of regulators and that was causing my problem.
I thought. It could have been the regulator, because when I took the cable "on & off" the post on the alternator a few times the draw stopped. I also noticed the case was warm even after setting all day. When did you talk with them? I may need to get in touch with them about mine. I put the stock one back on and no more current draw.
Freshman User
Joined: Nov 2006
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Yes I replaced it with another DB unit. The guy at DB said they got a bad batch of regulators, several people were having the same problem. He rebuilt me one with a Ford regulator in it and it has worked fine so far. I would definitely give them a call. I got the bad one in January. I'm on my third DB alternator within a years time.
Lead Driver
Joined: Jun 2003
Posts: 8,298
Likes: 24
From: Damon (South East Texas)
Yes I replaced it with another DB unit. The guy at DB said they got a bad batch of regulators, several people were having the same problem. He rebuilt me one with a Ford regulator in it and it has worked fine so far. I would definitely give them a call. I got the bad one in January. I'm on my third DB alternator within a years time.
Posting Guru
Joined: Jul 2006
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Thanks to all that have replied so far. I was just out doing some more checking. I had the digital ampmeter hooked inline with the negatives disconnected and was getting a reading of .017milamps. I pulled the #15 fuse under the dash and the reading went to zero. 15 is the GEM, PCM, ABS module and brake shift interlock speed control. Now I am really stuck! Anyone no where to go from here? Please don't say dealer. Thank you all for the help so far.
1500/.017 = 88235 hrs. This how long it would take to pull both 750 amp batteries to zero with a discharge rate of .017 ma.
What this means based on this information is you do not have a short. I suspect one of the batteries has a bad cell and needs replacing. Replace both and based on the .017 ma draw I think you will be ok, given your alternator is working properly.
Hotshot
Joined: Feb 2007
Posts: 10,499
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From: Sterling Heights,Mi
1500/.017 = 88235 hrs. This how long it would take to pull both 750 amp batteries to zero with a discharge rate of .017 ma.
What this means based on this information is you do not have a short. I suspect one of the batteries has a bad cell and needs replacing. Replace both and based on the .017 ma draw I think you will be ok, given your alternator is working properly.
What this means based on this information is you do not have a short. I suspect one of the batteries has a bad cell and needs replacing. Replace both and based on the .017 ma draw I think you will be ok, given your alternator is working properly.
