Incredibly, I actually managed to get both the dual battery system and on-board air setup ready in time for the trip.
Well—almost.
The wiring at least is in place.
Since space in the Tacoma is extremely valuable, I knew finding a location for the air tank and 2nd battery would be a challenge. I also have ABS—which means room under the hook is non-existent. I thought about placing both in the bed of the truck—until I read Scott Brady's regret doing this. Instead, he suggested mounting, 'at the frame level' to conserve space.
After much thought, I decided to relocate the starter battery underneath the truck on a custom crossmember. Alongside the battery (Optima YellowTop D34/78), I could also mount the 4 gal air tank. A massive Odyssey 1700MJT would replace the original stock battery under the hood and serve as the house battery instead (since 90% of all my electronic accessories are closer to the firewall). A custom tray & mount would need to be fabricated for a custom fit (thank-you Custom 4x4 Fabrications!
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Until the new crossmember is made, the connection to the starter batt is temporarily bypassed. The alternator and stock fuse box are temporarily connected directly to the house battery. This explains the few feet of extra 0/1 gauge wire you can see beside the positive terminal in these photos.
I also added a Blue Sea 12 circuit ST blade fuse block. All accessories run through it except for the winch, air compressor and 2m radio. Rockford Fosgate distribution blocks and terminals were used throughout.
Altogether, this project took longer than anything else I've done on the truck. For your viewing pleasure, below is the wiring diagram—reflecting the countless hours of research, preparation and trial & error I went through. I hope it helps all of you interested in doing the same type of configuration.
The 250 amp Xantrex PathMaker batt controller is mounted inside the cab, almost exactly the same as in bajataco's setup...
All wiring is neatly tucked behind the controller, beneath the door trim and through the firewall.
