BA Outfitters specializing in custom Fabrication of off-road accessories

This page is a work in progress !!! I am uploading it as I work on it.

Dual battery install on a ’76 FJ-40

My intent with these tech pages is to outline the entire process for these modifications.

This includes brainstorming the mods that I want through fabrication and completion of the project.

General Resources

www.ih8mud.com (Funny.. this shows up every time I do research)

www.birfield.com (The landcruiser mailing list archives)

www.pirate4x4.com

www.dogpile.com (Searching for individual sites and write-ups.)

Individual Links researched

Isolator write-ups

http://yarchive.net/car/rv/isolator.html

Great write-up on relays vs. isolators

http://www.geocities.com/nuguy56789/surge_protector_isolators.htm

Thread off Ih8mud on a dual battery tray build.

http://forum.ih8mud.com/showthread.php?t=62263&highlight=battery+isolator

Tiny write-up on Dual battery set-up with Electrical hook-up diagram

http://www.mphtower.com/am/lc/lc_dualbatt.htm

Decent write-up using just a battery switch (Jeep write-up)

http://www.pirate4x4.com/tech/billavista/dual_battery/my_dual_battery_setup.htm

Thread off race-dezert.com

http://www.race-dezert.com/forum/showthread.php?t=4751

Slee-Offroad write-up of their setup

http://www.sleeoffroad.com/technical/tz_dual_batteries.htm

Isolator vs. Relay vs. Switch

Isolator Pros

Automatic

Guaranteed isolation of batteries

Batteries can be different types

Isolator Cons

Voltage drop through isolator (This can be worked around with an external regulator)

Automatic

Relay Pros

No voltage drop

Each battery sees proper charging voltage

Cost

Ease of installation

Relay Cons

Batteries are not isolated when the alternator is charging

Requires similar battery types

Cost

Battery 1-2-Both Switch

Pros

A way to manually lock out all electronics connected to the wiring system

Could prevent theft

Can fully isolate systems.

Cons

Requires manually switching to charge each battery and to use each battery

Potential battery/alternator damage with switch misuse; ie. switching to off while the alternator is charging.