It’ll run high, 1300 lumens for about 1.25 hours with the Samsung 50E 21700. Holding a light lets your hand act as a cooling conduit as does colder weather. It’s shear mass allows the sitting by itself for 30 minute run time. It could probably run the whole 1.25 hour. It would however be to hot to pick up and hold that way. I live in warm to hot Texas. In cooler Yankee lands it’ll stay cooler.