As for runtime, I’d guess around 2 hours. I can’t find amperage numbers for DeWalt’s packs, but most of the competition’s 18v packs use 2400mAH cells. 18 volts times 2.4AH yields 43.2 watt-hours. The bottom of that isn’t usable, so let’s say 40 watt-hours of usable energy from a brand-new pack. The bulb is rated at 38 watts, which would give about an hour from one pack, but since the unit takes two packs, let’s guess two hours. In reality, slightly less because of less-than-perfect efficiency in the inverter circuitry, and substantially less if you’re using old batteries.

However, 38 watts into a fluorescent will produce the same amount of visible light as a 200 or maybe a 250 watt incandescent bulb. This sucker is seriously bright!

Anyways… I really like this thing, and I see myself buying it if I ever come across one at a better price. I have the snake light thing they make and I think that thing is brilliant