Battery Drain
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5th Wheeling
Joined: Apr 2009
Posts: 45
Likes: 0
From: Charlotte NC
Battery Drain
Does anyone have any idea what would cause a suddden battery drain? I have a 94 f250. The battery charges up fine and holds a charge until I put it back in the truck, then overnight it is dead. Any suggestions are much appreciated!
Posting Guru
Joined: Dec 2008
Posts: 1,226
Likes: 5
From: Rusty, Maine
Take a multimeter and measure the amp draw with the Key OFF. To do this put the meter to DC Amps and put your meter leeds in the correct sockets. Hook up your positive cable to the battery and put your meter in series with the negative cable and the negative post on the battery. While you have the meter hooked up start pulling fuses untill the meter goes to zero. Remember to have the key Off.
This will allow you to narrow your seach to 1 circuit. Then you can go from there.
This will allow you to narrow your seach to 1 circuit. Then you can go from there.
Post Fiend
Joined: Apr 2004
Posts: 6,473
Likes: 4
From: Lafayette, IN
What's the voltage on the battery with the truck off and running? Also, pop the vent caps off the battery and measure the voltage between each two adjacent cells (1-2, 2-3, ...5-6) and tell us the 6 numbers you get for those.
This is an easier/quicker check and should be done before the other one mentioned to make sure the battery is good first before you start looking for parasitic drains in the truck's wiring.
Jason
This is an easier/quicker check and should be done before the other one mentioned to make sure the battery is good first before you start looking for parasitic drains in the truck's wiring.
Jason
Post Fiend
Joined: Apr 2004
Posts: 6,473
Likes: 4
From: Lafayette, IN
Not to be argumentative, but an amp draw test requires the removal of a battery cable, which can be easy (or a major PITA), but checking the voltage of a battery and its cells doesn't require anything other than the voltmeter. Maybe a pocket knife to pop the vent caps off. Plus, the battery itself is a much more likely candidate for a problem. In hundreds of thousands of miles of driving, I've never had a parasitic drain, but I have replaced quite a few batteries--every 3-7 years, depending on the vehicle and battery.
Jason
Jason
Senior User
Joined: Mar 2009
Posts: 470
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From: Washington County, Penna
ok my truck does have a draw, the battery is brand new and has done perfect in my ranger ( its a 65-n, which is called for by the 250) but i put it in my 250 yesterday to move it around, it started perfect, left the battery in it overnight and today its dead as can be, my question is do i have to remove a battery cable to do the test as described by bigblueox?? if so would it be the negative i assume i would disconnect
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Posting Guru
Joined: Dec 2008
Posts: 1,226
Likes: 5
From: Rusty, Maine
You can do it on the positive or the negative but the negative is safer. And yes you have to take the cable off because the meter has to be in series in order to read amperage. They do make a inductive style clamp meter for measuring DC amps but they're pretty expensive for how much you would use it.
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Post Fiend
Joined: Apr 2004
Posts: 6,473
Likes: 4
From: Lafayette, IN
What voltages did you get on each of the cells? I had a fairly new battery that showed every sign of a draw--until I checked the voltages on individual cells and found a short internal to the battery.
Jason
Jason
