In setting up my FZJ80 for long range, self sufficent, expedition traveling, i knew that the addition of my 45qt Engel Fridge and 1500 Watt Vector Power Inverter was going to require an Aux battery setup.  I didnt want to risk damaging my starting battery and getting stranded!

I  wanted to install an aux battery to use for my accesories instead of possibly damaging my main battery.  I decided to go with a very simple dual battery setup and add a deep cycle marine battery for my accesories to draw from.  I want to set this up so that the accesories ONLY draw from the aux battery and never mess with the charge on my starting battery.  I think this is the safest way to do this. 

There are many writeups about installing the actually battery into the rig via the early style battery tray and how to relocate the windshield washer bottle, so i wont repeat on that.  Check these sites for info on that:

First off, one thing i didnt really notice in anyones writeup is the removal and rerouting of the resonator and the hose!  There is a hose resonator/silencer that needs to be removed for the 2nd battery to fit.  

The hose and resonator circled in green needs to be removed and a hose needs to be run where the red arrow is.  I used Napa hose Part # 9260 and it worked like a charm with a little trimming.  The ends are 2 different sizes, so you need to get creative on one side.  I just used some pieces of innertube to make up the difference.  With this resonator removed, it is a tad louder @ idle but nothing to worry about.

Here is a BEFORE pic (click to enlarge);

Here is an AFTER (not my rig, but you get the point)pic (click to enlarge)

Luckily, a very simple and straight forward diagram/schematic is included with the BlueSeas 4 Way Switch is exactly what i wanted.  

I decided to use a very simple manual switching design as opposed to the automatic ones with relays and isolators and such.  I want to keep my rig as simple as possible to make it easier to diagnos any problems when out in the middle of no where!  Boats have been using this setup successfully for years!

Parts List

Some Pics Of The Install