I use a 3/4" AllFlow Kynar AODD pump run off our big compressor. We run a 1" AODD pump on the rig, and this was the smaller pump we replaced. Makes reasonably short work of SH transfer at 15 GPM. The Delavan will get fried pretty quickly running pure SH thru it unless you rinse the heck out of it...and even then it will fry, so have a backup pump or risk not being able to charge your tank. Plus it will take forever to fill the tank at 5 GPM...but then again I am impatient and spoiled by lots of flow.
If you are set on using it...why not simply run a 12v lead into the pump from your truck from the battery? They make high amperage marine plugs that would work. Just put a connector on the truck and plug the lead in when you need to run the transfer pump. You will want big cable...4/0 is a good compromise.
Also...remember, those pumps are not designed for continuous duty. If you pump a large tank...say run 50 gal of SH into a 150 tank for a 33% mix, that is gonna take 10 minutes. That pump will overheat and fry itself if you run it that long continuously. Some way to cool it is a good idea.