Over the last few days I’ve installed the dual battery system in the FJ.
Off Road Downunder battery tray kit, supercharge ‘allrounder’ 105ah calcium battery, Redarc BCDC1225 DC-DC charger.
The tray kit installed faily easily. I did have a little trouble with one of the power steering hoses, but nothing the heatgun couldn’t help with.
If you want to fit a decent battery in here (100ah), you could go about a max of 305 to 310mm long. You will need to gently bend the alloy a/c pipe, and re-mount it’s bracket UNDER the new battery tray, not on top. Works fine.
I mounted the Redarc unit on top of the fusebox, which seems to be one of the very few places left in my engine bay to install anything. (especially after the ARB Compressor went in). It’s squishy in there now!
Follow the Redarc install guide for your wiring and you will be fine.by