Dirty Parts Dual Battery Kit with Optional Switch
I installed the Dirty Parts 2007+FJ Cruiser/2003+ 4 Runner Dual battery kit in my 2004 Gen 4 Toyota 4 Runner. I purchased the optional in dash rocker switch upgrade. This is a Carling dual light switch which illuminates Green in the on position and Red in the Emergency jump start position.
The install was very easy and not very time consuming although I did have a faulty switch that was replaced by Dirty Parts. Had I not had this problem with the switch the install would have been straight forward.
The figure below shows the wiring diagram I used for the install. I labeled the solenoid prior to installation.
Installation of the battery tray. Since this was a kit for an FJ, I had to drill my own holes and make a shim for the rear. The solenoid attached to the side of the battery tray.
I removed one of the dash switch blanks and trimmed the opening with an x-acto knife to fit the rocker switch. The first switch I received was not functional and took lots of trouble shooting to determine this. Dirty Parts sent out a replacement and it worked just fine. Later on I replaced the original switch with incandescent bulbs to one with LEDs.
This is a three position switch. In the up position, normal operating position, when the engine is running both batteries are charging but the batteries are isolated when the engine is off. This prevents the main starting battery from being run down if accessories on the second battery drain it. In the middle position, both batteries are always isolated so the second battery also doesn't get charged. The bottom position is to use the second battery to jump start the main starting battery,
An Optima D34/78 Yellow Top 55 Ah battery was used for the second battery. A Blue Sea System ST Blade 6 circuit with negative bus fuse box was also mounted above the tire well. All accessories attach to the second battery via this fuse box. The one exception is the ARB fridge which attaches directly to the second battery with an inline 15A fuse.
The center picture below shows the overall position of the second battery in the engine compartment.