House Battery Installation

This has been a long time in coming as for over the years I’ve weighed the pros and cons of having house power for the main purpose of powering a fridge. With the addition of the rear work lights and circuit for charging and accessories, I also wanted the peace of mind of isolating the main battery from current draw while camping, so I did the install.

Planning this out was the main challenge since the Nomad has little room under the hood for a second battery. With the sleeping platform, though, there’s a spot that the CD changer once occupied under the right platform wing.

I just needed to remove that bottom corner trim and find some kind of platform and method of securing the house battery. This is where I end up in a big box hardware store where when I’m asked if I could be helped I just answer, “you wouldn’t understand.”

Trolling the aisles I came upon a mailbox base that’s about an inch high.

I cut its length down by a couple of inches and cut out the moulding to test fit the base.

I sourced a one inch strap with buckle from an old back pack and riveted the ends to the mailbox base, providing a way to secure the battery. Once it all check out I secured the base to the sheet metal below.

With the logistics of battery placement solved, I began sorting out the circuit. After much research I picked up a Keyline Battery Isolator Pro Battery kit.


This kit has a 140amp smart battery isolator that engages both batteries to charge while the engine is running. When the engine is stopped and when the voltage drops below the unit’s cut-out at 12.8v, the SBI disengages the circuit, isolating the start battery from any draw on the house battery.

The trick now was to find a suitable spot for the SBI and run the positive cables from the unit to the house battery and to the start battery.

I started the cable feed from the cabin, then working in opposite directions to make the best use of the length centering it for fitment at either end. I drilled a 5/8ths hole through the sheetmetal on the right of the footwell and then through the sheet metal just below the door hinge. I popped a grommet in and fed the cable through the two holes (could ‘t get a grommet on the exterior hole) and then fed the cable up and over the wheel opening, zip tying it to the existing harness that goes to the passenger door electricals. I fed the cable into the engine compartment, under the air intake and terminated it just beyond the headlight washer fluid reservoir where I decided to locate the SBI.

Working rearward I fed the cable through the trough used for the existing harness to the right rear corner where I’ve established the battery box. I added a ground strap as well.

Back under the hood I connected the SBI, mounted the unit and ran the cable to the start battery.

With all the cables in place, I disconnected the negative from the start battery, connected the negative and then positive to the house AGM deep cycle battery and then connected the positive and then the negative to the start battery, completing the house circuit.

As seen above, I added a 100a breaker in the house battery box and ran power to a second Blue Sea blade fuse block (the first is under the hood for auxiliary lighting) along with a ground coming from the same earth as the battery.

UPDATE: I’ve since cut in a 100a breaker between the house battery and the SBI and fashioned a cover out of a plastic paint roller tray to protect the breakers.

For reference below, the large image is through the passenger side door looking under the sleeping platform. The fuse block is mounted on the wheel well. I ran a circuit to a panel installed under the platform to provide power for the fridge and to charge accessories, along with a volt meter. I moved the circuit I installed previously to power the rear panel and rear work lights to this house circuit as well.

4 Comments Add yours

  1. Stephanie Curlee says:

    Great write of your efforts.


    1. ImNoSaint says:

      Just came across your comment – thank you.


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