Beam Comparison - Headlamp
Battery Life vs. Beam Distance - the above graph shows how beam distance at the brightest setting degrades as battery life runs down. We use the ANSI FL-1 battery run-time spec, which says run-time for the high mode is finished when brightness degrades 90% from its initial value. The ANSI standard is more stringent than what headlamp manufacturers use. They consider high mode run-time still OK so long as there's enough battery to produce light as bright as a candle placed 2 meters away (0.25 lux). We think the manufacturer's approach is deceptive and misleads consumers to believe the high output mode produces a long-distance beam much longer than it actually does.
Zebralight H600w Mk IV: we measured the maximum beam distance as 121 meters and the ANSI battery run time for the high setting as 3.1 hours.
Fenix HP25R: we measured the maximum beam distance as 182 meters and the ANSI battery run time for the high setting as 2.8 hours.