Typing this from my phone so hopefuy I get most typos. So about two weeks ago left work, drive maybe 10 minutes, and stopped to get gas. While filling up I left my headlights on. No big deal for 5 minutes you would think but battery only had 10 volts and wouldn't start. This is according to ultragauge and voltage was fine before I stopped for gas. Get it jumped and home and check connections at battery. Positive actually was a little loose so figured that was it. Tighten it up and good for a few days then go to start one morning and click. Take battery to get checked out and checks out ok . Connection seem ok but was possible back door wasn't closed so chauked it up to that. Well right now I am sitting in work parking lot to get a jump because after being here only 8 hours it has 9 volt according to gauge and wont start. Connection seem ok. All doors are shut so not sure why I am good for a week or more than not. First thought is loose ground but will that cause battery to discharge while just sitting there.

 

What voltages are you getting from the ultra guage while the vehicle is running?

Also try disconnecting the ultra gauge when you shut the truck off. I have heard a few rumors that the ultra gauges have caused a battery draw.

 

The ultra gauge should turn off when the car is turned off if it's in normal monitoring mode. I have been in between screens/functions, like let's say checking readiness monitors and turned off the car and had the UG stay on and drain the battery overnight.

Your problem seems more drastic.

My sisters Disco was discharging after a day of sitting. I did 2 things that fixed it.

1- hard reset buying disconnecting battery cables and jumping 10 gauge wire from positive to negative cable. (10 min)

2- stripped back 1" of 10 gauge stranded wire, opened up battery cable connectors,put wire between terminal and cable, and tighten onto post with wire inside for a tighter/better connection.

Unfortunately I did both, so not sure which one did it, but it's all good now.

 

I see 13.9 to 14.4 on average. I have the alarm set at 13v for the low and it has never gotten there. I figured the ultragauge had some pull but would think enough to cause a battery to die after sitting for 8 hours when there have been times the car has sat for 3 weeks and been fine. Like I mentioned once it literally sat for 5 minutes and was down to 10v and wouldnt start the car. I cant think of anything having that kind of pull so I figure I just have a bad ground. I have some 4 gauge wire sitting around from my car audio days so I may main ground connectors and clean up the smaller ones this weekend. Just seems that if I had a ground connection that bad I would see more issues. My clutch fan recently exploded and sent coolant everywhere so possible I just need to clean some things up so I guess thats going to be my first plan. Just seems random hows it acting

 

Dumb question:
What stereo is on the car? Stock=no problem add on not done right=dead battery.


My P38 eats batteries like candy, new battery full 100% trickle charge, let sit 3 days, DEAD. I am working on looking for a switch that is NOT turning off and draining the battery. I know it is not the UG tried that first, not the stereo (stock) BUT still hunting for it.
I am going to put an amp meter in the circuit to see what the drain is.

 

I would bet $100 you have a bad ground. I was having the EXACT SAME symptoms and found that my ground was lose. I relocated it to the acccesory bracket and have not had a problem since.

 

Anyone know what gauge the wiring is. Looks like 4 awg which I have some spare wire and terminals I can use if it is.

 

You don't have to go through all that. Just follow the ground from the negative post on the battery to where it's terminates on the frame( it might terminate somewhere else, but it's close). Then tighten it clean it off, whatever you want OR unbolt it and connect it to the acccesory bracket. Takes 5 minutes.