Draining the batteries

Check the specific gravity in the truck batteries . A bad cell in one of the batteries will do that . On GM' s you need to install the 40a fuse for the charge line to camper , is it installed ? Have the truck batteries behaved properly in the past ? An isolated or continuous duty solenoid would be a good idea .

mikakuja wrote:
Interesting problem.... Have you tried unplugging the camper from the truck to see if the issue is in fact caused by the camper??
It doesn't make sense to me that the camper batteries are remaining fully charged and the truck is dead unless there is a wiring issue.
If there is ignition relay that shuts the power off to the 7 pin connector there would only be one way I could imagine the camper draining the truck batteries without draining the camper batteries... Is there is a battery switch somewhere in the camper that is wired to allow the camper to use only the trucks power while the camper batteries are shut off??
If there is constant power to the 7 pin connector (with no ignition relay) the camper should draw from both systems and the 200 watts of solar should be more than enough to keep everything charged.

Cannot see the camper draining the truck either. I also would say unplug truck and camper and let it sit and see what happens. Could be a huge phantom draw in the truck.

Interesting problem.... Have you tried unplugging the camper from the truck to see if the issue is in fact caused by the camper??
It doesn't make sense to me that the camper batteries are remaining fully charged and the truck is dead unless there is a wiring issue.
If there is no ignition relay that shuts the power off to the 7 pin connector there would only be one way I could imagine the camper draining the truck batteries without draining the camper batteries... Is there is a battery switch somewhere in the camper that is wired to allow the camper to use only the trucks power while the camper batteries are shut off??
If there is constant power to the 7 pin connector (with no ignition relay) the camper should draw from both systems and the 200 watts of solar should be more than enough to keep everything charged.

There was no isolator in either my 2006 GMC truck or my Outfitter camper, and yes, if the truck sat for over a week it didn't want to start. I had an isolator installed, which solved this problem. Tom McCloud

When I got my 2016 RAM and went to have the camper put on, they checked to see if the RAM had and issolater.
Nope, so I had them put one in.

Otherwise, what happens when you pull the power cord from truck to camper... maybe it defaults to the Truck, dunno, but I would think if camper wasn't connected to the truck during that time, it might go to the camper batteries..

Just thinking out loud here... also, just in case, an inverter will draw power if on, might check that for power loss...

Hope that helps a little...