New member seeking advise

Hi-
Thanks for letting me join the group. I’ll start by saying that my 2018 4Runner is probably the best vehicle that I’ve ever owned. During the “off season” when we can drive on the Rhode Island beaches and sand trails it’s a favorite pastime of mine.
I’m in the process of building a “foamie” camping trailer. I would like to install a 20 Amp DC to DC battery charger to keep the house battery topped up while I’m driving. The wiring is pretty straightforward. Positive and negative 8 gauge wires running from the vehicle’s battery to an Anderson connection at the rear bumper. There’s a third wire that the charger’s manufacturer calls an ignition wire. It’s purpose is to not allow the house battery to draw from the vehicle’s battery unless the vehicle is running. It is suggested that this wire go to a fuse with a pigtail and be plugged into an unused slot in the vehicle’s fuse box. My question is what amperage fuse should I use and what would be a good spot to plug it in? It has to be on a circuit that is only energized when the vehicle is actually running.
I would really appreciate any guidance about this.
Thanks
Otis

 

Welcome from Wisconsin! Electrical!? It's a foreign language to me, but I'm betting there is a 'formula' for it.

 

Welcome. For that ACC wire you're gonna have to find a fuse with a multi Meter that is on with the engine or use a fuse tap (not recommended with an inverter) to something that is like the radio or something. I wouldn't put it on anything like a fuel pump or anything to be safe. My 2018 had quite a few unused fuse connections in the engine bay fuse panel to choose from.

 

Welcome from Arizona!

 

welcome

 

Welcome from the center of the bourbon universe.

 

Welcome from San Diego!

 

Sorry, no guidance on DC to DC charging, just a welcome to the forum

 

Welcome.