I want to convert my 80 F250 to dual batteries. I can't find any wiring diagrams. How do I wire it in? I have the brackets and a solinoid from a doner truck. May be it would be better to get a long battery cable and hook both batteries together. What do you think?

 

Original battery neg to ground, pos to starter solenoid as per normal, 8 guage wire from that battery to a battery isolater, battery isolater to fuse or something similar to pos of second battery, second battery neg to ground. That's how I did my '78 Crew Cab, no problems at all, run all extras off the second battery

 

It depends on what you want to use it for. Bouts21 is using his for aux power. You can get more complicated if you want the extra battery to help in starting, or for a starting back-up.

 

I would like it for a starting back up.

 

JCWhitney has a isolator with a built in crossover switch. Go to www.jcwhitney.com and type in "EMERGENCY START BATTERY ISOLATORS FOR 2 & 3 BATTERY SET-UPS " in the search box.