Does anyone have experience with either on a helmet? Or similar lights? Comfort, light output, battery life, etc.

The HL25 takes 3 AAA batteries, yielding 3 (NiMH) - 4 (alkaline) hours @ 150 lumens and 8-12 @ 50 (120-140 @ 4). 93g light, 116-138g total all up front, strap around the perimeter.



The HP05 takes 3 AA batteries, yielding 6-9 hours @ 150 lumens and 17-18 @ 50 (160-170 @ 4). 161g light, 206-254g total with the battery pack in back.



It'll mostly be for reading street signs, although I'd like enough light to ride using it as a primary light so it functions as a backup.

I'm sticking with lights that take removable batteries because I can buy AA/AAA cells at any convenience store in the world.

I discovered that in middle age my patience for riding outlasts daylight. I expect to spend 2 hours before sunrise and 4-5 after sunset on my next long ride, and should add another 4-6 hours in April with some of that in the mountains.

I like to ride 3-4 hours between water stops, although having accidentally missed some and not wanted to back-track I want longer battery life.

Consequently I'm upgrading my lights beyond what served for ~1 hour daily commutes .