I am very interested in adding an onboard batter charger for my 15' VIP. I currently have 2 batteries on the boat, 1 for the trolling motor and 1 for the starting the boat and all the electronics. I'm the guy that adds lights, speakers, and anything else that's cool to my boat so I am contemplating on adding a third battery so I can have the engine, trolling motor, and all other electrical components on separate batteries. I guess that leads me to my questions; should I worry about adding another battery? and what's everyone's favorite onboard charger and is it good for the amount paid?