I have rigged most all my fishing lights and most other things I have that run off 12V with reg house hold 110 plugs even my batteries are rigs like this, oh yes my battery charge also. I use a reg 3 prong 110 plug. The ground part is not hooked to any thing use it to keep from pluging the lights in backwards.
When I first rigged this way I was trying to save money from having to buy a onboard battery charge. I have all 3 of my batteries wired with a different color 12 guage outdoor wire. I also use a 3 way tee outlet for more places to plug into.
bad thing I can not use my lights if I go fishing with someone in there boat.