OT- extra battery in camper

Have a pickup camper with inverter. Plan to add a deep cycle battery in the camper, connected to inverter so pickup charges battery while driving, through the inverter cable which is powered through 7 pin connector in bumper. Can unplug at bumper at nite, so pickup battery does not draw down. Reminds me of recent issue on Tractor Transporting board, charging a winch battery on a trailer. Any issues with my plan?

use continous solinoid as from golf cart between camper batt and truck. only activated when truck is running, will prevent truck batt dead

What you want to use is a Battery Isolator. Once installed you will not have to disconnect ANYTHING. You can run the camper battery completely flat and the charge on the truck battery will NOT be affected. The truck will start and battery isolator will direct most of the charge current from the truck's alternator to the camper battery until the voltage of both batteries are equal. Then the charge of both batteries will come to full charge together. I have used them for years on a electric winch system on a couple of my truck. I have never had a dead starting battery from using the electric winch. Google Battery Isolators.

Kent

Depending on the truck, most newer trucks have a "trailer tow relay" that closes only when the engine is running to charge the trailer battery. Otherwise, the battery isolator is a good idea.

Can't help you with your electrics but if you ever wanted a pretty couple of acres to camp on for a weekend I could help with that. 110V 30 amp crows foot, water and dump station. 14' aluminum row boat if you wanna catch some bass in the creek. Best part is it's free.
6 miles So of Aitkin.
You know my number.
Jerry

1) Those 7 pin RV plugs indeed have a terminal to be used as an AUXILIARY (lights, camper battery etc) power source, if its wired to the trucks battery and camper battery, it obviously charges up the camper battery when driving.

2) If I were running a wire from the truck to the camper Id use at least 10 gauge stranded copper and use a 30 amp fuze or circuit breaker right at your choice of the hot battery voltage source on the truck to protect that 10 gauge feeder wiring. If you use bigger wire, bigger fuzes/breaker

3) HOWEVER you dont want to discharge the trucks batetry when youre using 12 volts in the camper so you can EITHER a) Unplug it or b) Use a solid state dual battery isolator which allows the truck battery/alternator to charge the camper battery but NOT allow reverse discharge current, or c) Do like my friend Wilson suggests and use a 100% duty cycle 12 volt solenoid so the batetries are ONLY connected when the truck is running.

Protecting the feed wire circuit with a fuze or circuit breaker is my best engineering and safety advice, I use breakers which automatically re set versus me havign to install a new fuze.

BE SURE AND RUN A GOOD SOLID DEDICATED GROUND. When I run those circuits back, in addition to the fuzed hot wire, I also run a 10 gauge ground wire and connect it from battery - to battery - via the plug, of course, which is also bonded to a good solid (I use stainless steel bolts with star washers and maybe even weld to a frame member) frame ground NOW THATS A CIRCUIT

John T

The diode type battery isolater drops .7 volts in addition to the conductor voltage drop of the conductors. The battery back on the camper is not going to receive a full charge.
An electric solenoid tired into an oil pressure switch on the engine. Will tie the camper battery to the alternator/starting battery .Only when the engine is running.