I’ve used some OLight headlamps over the years, and while I generally have good things to say, there are some annoying features of the brand that I don’t understand.
My buddy Vince from the Netherlands explains a crucial difference between his two OLight headlamps – the H35W and the H37W models in the video below. The problem occurs because the H37W dims the light far too much when it gets warm. Vince tests these headlamp units in 6°C! Not exactly a warm environment. If he was here in Thailand in 35-40°C, there would be a serious issue. Would it even turn on at all? lol. I’m sure it would, but you can see that this H37W may not be the right headlamp for you in warm or cold environments.
OLight H35w and H37w Compared (Video)
That is excaxctly my experience as well. I returnert the first one, and I got a replacement. Excatctly the same with the new one. Used in in zero degrees, and after a few minutes the lights dimmed down to under 1000 lumens.