I run a 400 Watt Power Inverter in my boat that I hook up to my trolling motor battery. It converts the DC power from the trolling motor battery to AC current. It has two standard 110 volt plugs on the power inverter. You can then plug in a standard light to use in your boat.
I use the new incandescent low wattage light bulbs which give you plenty of light with very little battery drain. I have a 23 watt bulb that puts out the equivalent of a normal 100 watt light bulb. I can run that all night off my trolling motor battery with no problem. It lights up the whole boat and out around the boat for late night catfishing. Works great.
One other thing – when the bugs are bad you can run one of those yellow bug lights and it works pretty good at holding down the bugs and still providing enough light to see well.
You can pick up a power inverter at any of the outdoor sporting goods stores (Gander / Cabelas / Sportsman’s Warehouse). My 400 watt inverter cost me about $30 on sale.
I made a 6′ high light pole out of 1 1/2″ PVC which mounts in my front casting platform seat mount. This gets the light up in the air so I get the most light coverage and it keeps any bugs up in the air too. It works pretty good. Here is a pic: