Slow battery drain ?
 

After several hours of looking through battery and electrical posts I'm need to ask for help.:confused:

2002 7.3. If the truck sits without being started fro ten days the batteries drain to where the truck will not start. They are not dead, I do not lose memory in the radio, interior lights work, etc.

Starting with a fully charged battery it drains 1/10 a volt per day, on day ten each battery will be at 11.6 volts. With every thing off the amp draw will settle to .3 after about 30 seconds. I assume this is computer and radio memory. Currently the batteries have been unhooked for 3 days and have held their charge. We went trough the process of removing one fuse at a time and found no circuits that would change the .3 amp draw except for computer/radio.

Is .3 amps the normal draw? If so, is this a normal occurance and should I just drive the truck more often. Are there curcuits that I still need to check?

All suggestions are appreciated.

Jim

Subscribing....interested in what the culprit will be

Almost a half amp? Seems high to me. Can you pop out your radio and see if that helps? Maybe your radio is freakin out. Easy enough of a test and your can rule out the radio then. I would think it should be in the milliamp range when the truck is off. I will run out and see if i can remember how to use my Fluke in the Amp setting and see what mine is running..

Edit: Just remembered something. I had a car a few years ago that did this. And the little light that is under the hood(when you open hood) was staying on. I went out one night for a smoke and standing next the the car i saw the glare off the driveway. The car battery would die after 3 or 4 days.. I pulled the wire and the problem went away.

Jim,
I had the same problem with my truck a while back. It ended up being the radio. It was drawing enough to drain 2 brand new Motorcraft batteries in about 8-10 days. I went through the same exercise you did. Pulled fuses till I found it, measured the drain etc. Megawatt guided me through it. I replaced the radio and haven't had a problem since.

Another thought. Did you try disconnecting your alternator?

Similar experience, my mom's old Expedition was eating her battery and it was the glovebox door light that was the culprit. Bad switch.

I got the FLuke out.. It shot to 1.3 amps for 3 seconds then It dropped to .216. (computer/radio initializing ?) No Hood light. I haven't had a battery problem. That know of. I Have the battery tenders on and batteries disconnected for winter storage but it sat a lot last fall and she fired right up after sitting a month. So unless i have a new problem that i am unaware of your .3 is a good number. Wierd. How hold are your batteries?

I have a similar problem. My batteries will drain in about 3 days in the winter and 7 in the summer if I do not drive it. I've checked the alt and replaced batteries twice. I'm still trying to find that gremlin under the hood.

The batteries are less than 2 years old and hold up under load test. Thought maybe a short so that is why they are unhooked now. I put a new alternator on after this started and it changed nothing.

I'm begining to think something energizes itself.....sometimes.}>

Thanks for all the input.

Jim

do you have an auto starter. my guess would have been the alt. easy to check, take the wires off and watch the amp draw. are the batts the same cca? do you have an aftermarket alarm?
try unplugging the radio as suggested above. when you are load testing the batts are they both unhooked from the truck and each other?

Nothing aftermarket except the Edge tuner. Batteries unhooked and matched set.

Haven't attempted the radio yet the shops full and its cold outside.

Jim

good luck with the radio. ill test my system tommorrow if i dont get called into work. just for a referance.
cheers

This post is old but I think the problem is solved. It's been a couple of months with no problems since we found a slightly loose connection on the new starter. I don't know if we had enough voltage drop that when the batteries were a little low it wouldn't start or what. Seems as though it is always the little things that get ya.

Thanks for all the help.

Jim

Glad u got it solved. I'm still having the problem after pulling fuses 1 by 1 and testing, and I still can't find the draw. I also put in new alt as well.

I'm having a similar issue with my '06 F250. I am getting a .45 amp draw even after the interior light delay times out. Everything off and all aftermarket equipment disconnected. Took it to the dealer and the tech thinks I may have a bad guage cluster ($423.00) but needs to confirm that with the ford engineering team as the interior light time delay and battery saver modules are apparently built into the cluster but detailed schematics of that component aren't available to the tech. I will post the results. By the way, the battery drain stopped when I pulled the fuse for the instrument panel.