I agree to make sure you use a Sealed battery. Most 12v 12amp batteries I've found weigh in the 8lb range. Should give you close to 2 hours or better of runtime, depending on light draw. If you can add a rheostat, you can extend battery life quite a bit. I have an old 300,000cp qbeam (old bright yellow light). I plan to buy a SLA battery, charger, & make my own filter for it. I have some foam to cut & fit into bottom of a camo soft day pack, for the battery to set. Still has enough room for other gear. I like this light as it has a flood/spot setting. The flood setting is even less candlepower, so it doesn't drain battery as fast. I forgot I had this light in garage. Dug it out, cleaned it up & tested it last night. Will be plenty light for hunting here in WV. Now if I can find or make a filter somehow.
Take care,
HS