I picked up a new 12volt sprayer system to use on the job site. It comes with those little alligator clips to hook to the battery but...I was wondering if there is a better way. I'm thinking about getting a deep cycle battery to use with the sprayer, but I need a way to keep it charged. The trailer plug on my truck ('04 Chevy k2500) has the center pin labeled as "aux power". Can I make up a plug that connects, only to that center pin, run that to the d/c battery and charge it that way while I run the truck? I'm pretty sure that is how the battery on my dump trailer charges. Any thoughts?