Need helping wiring up 12v to fridge w/ relay

[austinado16]

The final bit of wiring for my '87 Starcraft Nova is to connect up the wiring to the 7 pin Bargman that will charge the camper's battery and power the fridge on 12v during towing.

How it was previously wired was the black "charging" wire, was simply scotch locked to the green "refrigerator" wire up on the tongue.  In this mode, the fridge got power when the tow vehicle engine was running only.

I've read where several of you mention installing a relay so the fridge gets powered by the tow vehicle during towing, and then when the tow vehicle is turned off, like during a stop to eat, fuel, etc. the fridge is still powered, but by the camper battery.

Sounds like a good plan, but could someone post a quick wiring schematic (hand drawn is fine) or instructions, and let me know which relay you've used?

I've got a Bosch single throw relay, but not sure this is going to provide the right function.

Thanks!

[austinado16]

Will this work?  I've drawn this out using a 40amp Bosch relay, which I'm familiar with using.

[AustinBoston]

That depends on what you want it to do.  It does the most important thing, which is protect the tow vehicle battery from being drained while parked.  But if you park for any length of time, the fridge will drain the camper battery.  If you will be using hookups, no big deal (except for reduced battery life), but if you are dry camping, you would not be happy.

Austin

[austinado16]

Obviously I wouldn't be running my fridge on 12v while camping and my deep cycle marine gel battery has enough capacity to handle the fridge load for about 4hrs. should I decide to stop somewhere and not switch over to propane.

Was just looking for someone willing to share their info on how to install a relay to disco the tow vehicle battery from the camper battery when the engine was off.