Battery keeps draining
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5th Wheeling
Joined: Sep 2018
Posts: 48
Likes: 0
From: Southeast KS
Battery keeps draining
I purchased the 82 F250 at end of September and put a brand new battery in it, since there was not one in it. A week and a half ago it started going dead on me overnight. I had it tested and they said it was bad. They swapped out batteries a week ago. I have driven it around and not been a problem until Monday afternoon I got home and jumped in the truck to go somewhere and it was dead. I charged it up and drove it yesterday to work and then home afterwards. Started up fine. Was dead this morning. I got it started and drove to work today and had to jump it to get home. I disconnected the second battery that sits under and behind the cab to see if I can figure out what might be draining the main battery. I will get this battery tested to make sure it is not bad. Any ideas. The charging gage shows it is putting out a strong charge to the battery.
Tuned
Joined: May 2013
Posts: 396
Likes: 5
From: Ottawa, Canada
Verify you have good clean grounds between engine battery and body.
Get out a multimeter and try some of the following. 1. Disconnect the battery and check the amperage going to the truck with the key off. If you get a reading pull fuses one at a time and see if you can find the issue. (Make sure a good fuse is in the multimeter)
2. With the truck running put the multimeter on AC voltage and check the battery terminals. Should be about zero or the alternator may have a bad diode.
With the truck running you should have 14+ volts. After it shuts off and sits for a while a full battery should be around 12.6.
Get out a multimeter and try some of the following. 1. Disconnect the battery and check the amperage going to the truck with the key off. If you get a reading pull fuses one at a time and see if you can find the issue. (Make sure a good fuse is in the multimeter)
2. With the truck running put the multimeter on AC voltage and check the battery terminals. Should be about zero or the alternator may have a bad diode.
With the truck running you should have 14+ volts. After it shuts off and sits for a while a full battery should be around 12.6.
Lead Driver
Joined: Apr 2002
Posts: 5,339
Likes: 1,248
Another check for shorts...with key off remove the negative terminal and test for DC voltage between the battery terminal and ground. Should be zero. If you have voltage it indicates a short.
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5th Wheeling
Joined: Sep 2018
Posts: 48
Likes: 0
From: Southeast KS
It was ordered that way because he had a camper on the truck. There is a silver box on the firewall that is supposed to protect the battery system with an accessory or auxiliary battery..
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Moderator
Joined: Jan 2001
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From: Virginia
Here is a easy to test for a drain on the battery. If the testlight lights up, you have a drain. You can go around and pull fuses to see if the light goes out, if that doesn't work then you can take the wires off the alternator and see if the light goes out. Make sure you shut the door, the domelight will be a drain and cause the light to light up.
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