Bob 3500HD

NY to SC and back going 70-80 got 15.8 according to the truck electronics. I didn't keep track of the actual gas input.

Surprised there is nobody complaining about the gooey frame coating. I installed torquelift camper tiedown brackets and ran some wiring and it is pretty messy. Have to wipe it off the tools and scrub off my hands and arms. Maybe mine is extra gooey? Hopefully this coating does a good job preventing rust. I picked up a can of the repair spray and hit some of the areas where it was scraped off when they assembled the truck.

If you weld the adapter to the bike rack that will remove half the slop. Then maybe run some weld beads on the OD of that with some grinding so that fits snug in the 2.5 inch receiver.

If you’re not pulling from the truck battery you shouldn’t have to worry. If so, it draws from the secondary battery and leaves the primary fully charged

I'm just guessing now because the wiring harness is all a big bundle. But it would make sense that the 100A is the 100A at the other end at the secondary battery. Also, the 175A probably goes to the main fuse box. There's a heavy gauge line that hooks up there.

My 2018 2500 Ram beat me to death. My new 3500 double cab long bed with snow plow package rides like a Cadillac compared to the Ram. I guess it's relative.

To confirm what George said I checked the power lead in the 7 pin with and without the 30 amp connection off the secondary battery being connected. Just like was described, the 30 amp lug off the secondary battery supplies the power to the camper with the battery isolated with the truck off. Thanks everybody. I think this is solved.

If the starter battery is drained by my camper with the truck off I don’t see how the secondary battery can start the truck through that 100 amp fuse

Here is the fuse layout on the starter battery. The 400 amp goes to the starter. The 250 is the alternator. The others disappear into the wire harness

Nothing in the owners manual and I've searched my ass off on the web. Seems like GM would have some sort of written explanation published somewhere

There is an isolator. But it looks like it’s on the secondary battery. I’d just like to understand how the whole thing functions. For example, which battery drains

My 3500HD came with dual batteries. Trying to figure out how they function. The passenger side battery is connected to the starter and alternator (starter battery). The drivers side battery has an isolator switch on top (backup battery). I assume the backup battery is isolated with the truck off. How do the batteries drain at that point? If I run my truck camper off the truck batteries does it drain the starter battery or the backup battery? There is no information I can find anywhere on how these are wired up and function. The information I find on the web seems to be that the isolator should isolate the starter battery. It doesn't look like that on my truck.