Having a strong electronics knowledge, there’s an easy way to power these lights off a 12 volt marine or deep cycle battery.  Just look at the voltage and current requirement and use a 78xx regulator inline. (7812 takes in 12+ volts and puts out 12, 7809 takes in 12+ and puts out 9 volts, 7906 takes in 12+ volts and puts out 6 volts).  You get my drift here, and are available at Radio Shack for a couple of bucks. I believe they’re good for about 1.5 amps on draw, which should be plenty for a LED setup. If you’re afraid to pull out a soldering iron, contact your local ham radio club or electronics school.. Pretty sure someone will be willing to set you up quickly.