Whos installed dual batteries on their truck?

I'd like to add an extra battery in my truck, its mainly a tow vehicle but i'd like a little extra juice for my winch, and inverter to power stuff up for those long days at the track. What do I need to do?

Dodge diesel comes standard with duals.....Comes in handy, and can't hurt.

Knowing what year & size your truck is might help. i used to run the 73-93 trucks with 2 batteries on the original platform, turned sideways. I just connected the cables + to + and - to - and ran a 100 amp alt. Gene

86 3/4 ton