Like the title says, if it sits over night the battery will be about dead. The cables were replaced 6 months ago and are in good shape. I could not find and bad spots on the wires I can get to. One odd thing to note, with the key out of the switch I opened the passenger door to check the glove box light and the truck started chiming like I had opened the drivers door with the key still in the switch. Would that indicate maybe the key switch could be the issue? Thanks

 

Key switch could be worn out, I'd start by checking all the fuses and see which ones are pulling power with the truck shut off (Parasitic drain).

 

Start with the basics. Get battery tested. Don't assume good. Then voltage at battery when engine shut off. Take a significant draw to kill a battery overnight. After five minutes check amp draw down at battery.

Steve

 

Battery is tested and good. Starter was also replaced 6 months ago with the battery cables.

 

Unhook the battery overnight. Load-test it before hooking it back up in the AM. If it fails the load test it's a bad battery. If it passes the load test, hook the battery back up and see if it starts it up. If it starts right up its time to ferret out the short. Do you know how to systematically trouble the trucks circuits to find shorts?
What's the alternator output at warm idle? Put a VOM on the battery when you shut it off to see how fast the VDC drops. It will drop off from say 14.5 vdc quickly but it should level off and sit at about 12.6-13.2 for a good surface charge. That surface charge reading should stay level for days in a good battery with near zero milliamp draw.

 

Good. So you going to have to isolate the draw. When you go to start in the morning do you know what you battery voltage is?

 

Has anything been added or changed on the truck ?

 

Do you know how to read amp draw? Much faster than working with volts. Gives you real time load on battery. If you know someone with a clamp meter takes only minutes.

 

Nothing new except the starter and battery cables in October of last year. This was done out in the woods where the truck decided to not start after cutting wood for a few hours. Not the most fun I've ever had.

 

I have a Schumacker BT-100 battery tester. The battery after having sat for a couple days shows 12.8 volts and passes the load test just fine. I don't drive the truck much and after discovering I have an issue with it I have just left the battery unhooked until I get a chance to work on it. I see I posted my "nothing new" reply in the wrong spot.

 

I did the "How To Perform a Parasitic Draw Test - EricTheCarGuy" on Youtube test like he did and I get 1.2 amp draw with every thing shut off. Now to figure out what is doing that.

 

When it comes to a parasitic battery draw, or if I think I have one, I just take it to a buddy I know (powerstroke specialist, transmission specialist) and he will charge me 1 hr shop time to check the draw. Much faster than trying to figure it out myself.

Thats what I suggest.

The only reason I suggest that is so you can get it figured out quicker.

 

hard to see how that would crush a battery overnight.

 

I'm learning some new tricks with this one. The truck had been sitting for over a week when I first discovered the dead battery. I put in my spare battery and made my trip, then the truck sat overnight. It started the next day but barely. When I got back I disconnected the negative until I could spend some time figuring it out. I had never done a parasitic battery draw test before but I "think" I've traced it to the left rear of the truck. Thanks for knowing which questions to ask.

 

Superdutys are bad for this parasitic draw!. I have two dutys and both will be dead after a week if the trucks haven't been used. I had one truck checked out at shop and he said it had a "normal" draw for a duty.