'22 3500 HD dually unknown parasitic draw. Common issues?

[snlsmith]

A couple weeks ago I tried to use the remote to start my truck and I just heard a click. Tried to start with the pushbutton and same thing. Threw it on the tender overnight and started fine so figured it was just low. Three days later same thing and measured the battery at 10.6v. Back on the tender, same thing, started fine the next day. Fast forward a week and when I opened the door the auto-extending running board didn't pop out. This time measure at 7.8v (may have just jacked the battery this time). After being on the tender for a few hours, opened the door and the step came out. Closed the door and stayed to watch the lights. Every light (overhead, back seat cargo LEDs in the seats, bed) as well as the dash turned off, so no lights staying on that I could see. I also have nothing plugged into the front/rear/armrest USB ports, AC outlet, or DC outlet on the dash above the radio.

Battery tender was green this morning showing a full charge, so going to disconnect the negative cable and hook up a multimeter to start testing, but would be nice if I had something specific to check first.

Possibly a coincidence, but last night I remembered that during our last trip a month ago, the USB outlets by the rear seat AC vents did not work. The cable itself was good as we just moved it to a USB port on the dash and the phone started charging. If you know exactly what fuse that is it would be appreciated as the fuse descriptions are not very clear.

 

[AH64ID]

Your factory batteries are probably shot. They often don’t last 3 years, and so me they have drained that low multiple times it’s definitely time to replace them.

Are you keeping a key fob in the truck?

Battery tenders are a good idea for longer battery life if you don’t drive the truck every few days, all the electronics/computers wreak havoc on the cheap batteries available today.

F66 is labeled as the USB rear fuse in my ‘22 owners manual.

 

[snlsmith]

Your factory batteries are probably shot. They often don’t last 3 years, and so me they have drained that low multiple times it’s definitely time to replace them.

Are you keeping a key fob in the truck?

Battery tenders are a good idea for longer battery life if you don’t drive the truck every few days, all the electronics/computers wreak havoc on the cheap batteries available today.

F66 is labeled as the USB rear fuse in my ‘22 owners manual.

1. It the battery from Ram any different than the one that shipped from the factory? Or should I buy elsewhere.

2. No FOB in the truck

3. Usually not on one, but probably will be in the future

4. Will check it out this afternoon. I did check the fuses and several failed the push test and seated in better. Didn't want to open the door again to re-waken the computer, so will check this afternoon to see if it was fixed.

UPDATE: Battery tender light was green, but batteries were only at 11.1v, so yeah, they are shot. Got out my clamp on meter and rear 4 amps at the neg post on the drivers side battery. Really confused at how high it was, but then remembered I had gone on the cab to double check the no-power status of the rear power ports. From what I have seen on some vids, that would have woken up the computer and it needs about 45 min for it to fully shut back down. Went back out a bit later and reading 1.2amps. Left it off the tender to check draw down, and this morning it was at 10.8v, so about .3v over 10-11 hours.

Going to pick up two new batteries today, but still have to figure out what is causing the draw.

BONUS: Supposed to be hooking up the 5th Wheel tomorrow to head to the track for my weekend races.