Thanks for those tests. They confuse me even more in combination with this test.
Scroll down to about 3/5 of the page.
It shows the effiency of various headlights.
Olight 133 lm/W.
Skilhunt 123 lm/W.
Armytek 94 lm/W.
Zebralight 67 lm/W.
Assuming I uderstand things correctly; to provide a 600lm beam the Olight uses 4.5 Watt. The Zebralight requires 9.0 Watts.
That would not only mean the Zebralight has half the runtime at the same output, but also has a extra 4.5 Watt of heat to dispensate, which makes stepdown more likely.
The XHP50 max output is 149lm/w. 4 Watt at the tested 600lm.
Olight requires 4.5 Watt. That’s 0.5 Watt system losses.
Zebralight requires 9.0 Watt. That’s 5 Watt system losses.
All that said it’s hard to understand how a few watts can overheat a light so quickly.
My main point is that the Zebralight should have twice the thermal problems as the Olight has. Does that show in the the stepdown graphs?
To at least get some specs I used the numbers from this light.
Very hard to compare because tests use different generation light and leds. Also the cell used for testing is diffrent. But personally I see no proof that the lm/W performance is half of the Olight. I’m not saying te reviewer was wrong, but I truly want to know what causes those (seemingly) contradictions.
For me personally lm/W is a big selling point because it affects runtimes and stepdowns.