Those LED worklights are fantastic and i love mine, they are very directional so i don't think i'd fancy lighting up a garage with one or 2 of them. You really want something more like a strip light on the ceiling i'd have thought?
You can get 12v LED strip lights and wire them in to a car battery? I've done this in my shed, i've got a small 20watt solar panel which keeps the battery topped up but even without this you'd probably only need to take the battery to charge every few months.
Look on eBay and the like for campervan conversion lights, or any automotive stuff as that'll all be 12v