Joe H has it pretty well mapped out for anyone to find the best option that suits them.
You will need a voltmeter. Some of those trucks have a cig lighter. There are plug in voltmeters that work well.
Attachments
volt.JPG (28.77 KB, 69 downloads)

~ BD.
"You won't find me in an old folks home" Pioneer Florida Cracker
1958 Apache Stepside
1958 Apache 1/2 ton Panel
1959 Apache 1/2 ton Panel