I've got an older GoPro with both a chest as well as a head strap that I can use when recording. The battery life lasts almost 2 hours per battery of which I bought a second one just in case, and the new ones last supposedly just as long or longer. I'm of the opinion that if I haven't limited out while fishing for 4+ hours then the fish either aren't there, they aren't biting, I need to change my setup or go in for a break and then come back out. Either way, 2 batteries along with bringing the battery charger with you should give you as much time as you'd ever likely need. And I like using either the chest or head strap because you can leave the GoPro on and hit the record button whenever you've got a bite. That way you aren't recording hours and hours of nothing and draining your battery even faster for no reason. You could even leave your camera off until you get a bite, turn it on quickly and then hit record in a matter of only a few seconds as well. You can also use the GoPro application on your smartphone and record it that way if you really want to mount the camera to the roof or somewhere else. Or they even make a remote that you can use to hit record for a mounted camera as well. There are a multitude of options out there at different price points, but I don't think you need a dedicated or external power source just for your GoPro.