Originally Posted by
KhunMoo
CraigE, Another alternative is what I call the "A & B battery" approach, where you install two identical batteries under the 110 passenger seat and connect them to the main cable using a Cole Hersemann switch mounted on the front of the battery box under the passengers legs. I also run a new 50mm2 earth cable across to the transfer case (std LR earth cable is pathetic).
I use two Supercharge Gold MF batteries that you can buy from most auto sparkies for $135 each. They are identical technology to AC Delco's with about 700CCA.
This way you can treat the batteries as simply A or B or A+B when required. You have a very useful fourth switch position called OFF. Very necessary for when the inevitable LR electrics fire starts one day.
I usually switch to the fresh battery before morning start up, run that one for an hour (watching the voltmeter) then switch back to the other one for the rest of the day to get it fully charged for the upcoming night. I have also checked the calibration of the dash voltmeter so I can see what's going on.
This approach means I don't bother with deep cycle batteries (which alternators can never fully charge anyway), I can get a replacement anytime, anywhere and it is ridiculously simple.
KhunMoo