I want to put a dual Battery system using an isolater. My question is how can I put a switch in the cab so if my main battery goes dead I can switch over to the other battery. I hear people talking about a starter relay. What is that and how to you hook it up? Thanks

 

I answered this once before for you but here I go again. https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=4018&.jpg

Using this pic I drew up you can set up a "self jumpstart system". You run some heavy gauge wire (#6 or heavier) from you aux bettery to a starter relay then to your main battery or main starter relay. Then run some 10 guage wire from the pos of your aux battery to a switch in the cab then back to the S terminal on your second starter relay. Make sure to put a fuse inline. Make sure to make good conncetions every where and heat shink all of the connections.

A starter relay is what the pos of your battery goes to. Then has a wire coming off that goes to your starter. It is usualy mounted on the passenger side fender it has two large lugs on the side and two small posts on front.

Hope this does it for you if you have any questions just ask.

 

Thank you very much