Any mod needed to ensure camper won't drain truck battery?

[dogbreath650]

I usually disconnect the plug from the camper to my truck when parked but just in case I don't for some reason I was wondering if it could drain the truck battery. In my older truck I seem to recall having a mod done to make sure this wouldn't happen. Is something along these lines still recommended with the newer trucks? Thanks...

 

[AH64ID]

If you’re going to leave the truck connected then a voltage sensing really is a good idea. I’d tap into the 12+ wire for the 7-pin under hood.

Blue sea makes a nice automatic charging relay that would work well.

https://www.bluesea.com/products/7601/m-Series__Automatic_Charging_Relay_-_12_24V_DC_65A

 

[jabartram]

Add a second battery

 

[AH64ID]

Add a second batteryView attachment 51317

Do you mean a 3rd? He already has two…

But just adding a 2nd battery doesn’t do anything for the 7-pin drain unless you wire in a VSR.

 

[CdnHO]

If you’re going to leave the truck connected then a voltage sensing really is a good idea. I’d tap into the 12+ wire for the 7-pin under hood.

Blue sea makes a nice automatic charging relay that would work well.

https://www.bluesea.com/products/7601/m-Series__Automatic_Charging_Relay_-_12_24V_DC_65A

If there is an isolated battery charge line in the trailer, you can also connect it there.

 

[AH64ID]

If there is an isolated battery charge line in the trailer, you can also connect it there.

With voltage loss they are reported to not work as well in the camper.

 

[CdnHO]

With voltage loss they are reported to not work as well in the camper.

Good point. But if it works, it saves you from hacking into the truck wiring. I don't have a schematic but i don't believe there is a separate wire coming from the battery for the 7-pin. I think it is powered through the fuse panel. Easy to wire the device to the trailer battery if there is a separate wire to test it.

 

[H3LZSN1P3R]

You could easily take the trailer 12v+ pin wire at the front of the truck and make it go to a relay thats only triggered when the ignition is on

But really unless you are running the furnace 24/7 and every light for a full night you wont drain your batteries in the truck