It’s temperature regulated. It isn’t as sophisticated as a really well optimized PID, but it stays brighter longer when you keep it cool. Even bounces back after stepdown if you manage to bring the temperature down enough. At some situations this may result in slow oscillations as the light climbs back to full output and steps back down after heating up again.
Without cooling on turbo and high my sample steps down to about 820 lumens and stays there in room temperature (23c) without additional cooling. Surface temperature is about 50 degrees. Most lights this size can’t retain 800 lumens without cooling or burning your skin.
Thanks for the graph! I think if the light was set at 1,200 lumen mode, the oscillation would be farther apart and less pronounced. Maintaining true 800 lumens is really good for this size light. But it is 21700 host so should have more mass. Someone should suggest to Wuben to add a sustainable 800 lumen mode.
Maukka do you have the weight without battery? I just want to see how it compares with the TO46R. The thermal performance of the TO46R is pretty good already but I hope this added a good amount more mass since the output is so much higher.
(I don’t have a flashlight that uses LH351D yet… and 5000K CRI 90 sounds good)
… at least until the FW3A gets released (hopefully in XPL-Hi and LH351D versions)