The lights I'm changing to now are rated 18 watt, but are also available in 3 -15 watt, too. I picked the 18 watt because it had about the same light as a 100w bulb. See picture. It comes with a power supply that is marked ac 85-260 volt incoming. I have a large inverter
system that is always on, but you could run more than 2 dozen of these lights on a small 500 watt 12v to 120ac inverter. I paid $18.50US each light.
I have a wood boat. The edge of the light is about the thickness of a saw blade kerf. So I took trim wood and made boxes with an inside groove that holds the light. I replaced 120 ac florescent lights that were protruding below my overhead beams. These new lights tuck in between the beams and give more headroom
and more light. And they're small enough to fit places the florescent fixtures don't fit. Hopefully lasting longer that florescent bulbs.
I got these on Amazon, but Ebay probably has them, too.