My goal is to have an ultralight headlamp for backpacking (1 oz with batteries would be nice) that will put out 4 to 10 lumens with a run time of 20 to 30 hr. I know of a few commercial headlamps that come close, but each has shortcomings. Since I am an electrical idiot my general question is, can they be modified?
First, I'll mention what should be the easiest headlamp to modify. The Coleman Exponent Mini Headlamp uses a Cree XR-E LED powered by a 3V CR2 battery. The switch cycles off/high/low/strobe. The run time for low is 6 hr at an estimated 21 lumens, and the high is 2 hr at 75 lumens. What would it take to modify the headlamp to obtain a low of about 5 lm and a run time of about 25 hr? Is that modification plausible? For my purposes, the low is all I need. I don't care if the modification loses the high and strobe settings. If it has multi settings, the headlamp would be more useful to me if the low came on first.
Second, the headlamp that comes closest to my ideal is the Black Diamond Ion. The Ion is sufficiently bright for camp chores, weighs only 1 oz, and has a nice on/off switch that is easy to operate with one hand and doesn't turn on in the backpack. The problem with this headlamp is the insufficient run time and comparatively expensive battery. The Ion takes a 6V 4SR44 silver oxide (or PX28L lithium) that has a meager capacity of about 160mAh or 0.96Wh. The headlamp has two light settings, a low (11lux @ 2m, run time of 15hr) and a high (30lux @ 2m, run time of 3hr). Black Diamond's optimistic run times are not computed the CPF common way of time to 1/2 brightness. The short run time problem is mitigated to some extent by carrying a spare battery, but a spare means more weight and the 4SR44 batteries already are more expensive than the more common types such as the CR2. I don't know why they didn't use a CR2 battery instead of the 4SR44. The CR2 is only 1 gram heavier and a couple of mm bigger (in length and circumference), but holds more than twice the watt-hours. I assume the Ion would be more difficult to modify than the Coleman Mini.
Third, it should be possible to create a headlamp from scratch, although the housing may be difficult. For example, I could start with the head of an iTP A3 Eos or A1 and run it from a CR2.
The Zebralights, Princeton Tecs, and Petzels are too heavy for my goal of 1 oz and small size. Even the Coleman Mini weighs 1.4 oz. This ultralight headlamp is for camp chores. I will carry an iTP A3 Eos and spare L92 battery for emergency night hiking.
Thanks for any feedback.
-Scott
First, I'll mention what should be the easiest headlamp to modify. The Coleman Exponent Mini Headlamp uses a Cree XR-E LED powered by a 3V CR2 battery. The switch cycles off/high/low/strobe. The run time for low is 6 hr at an estimated 21 lumens, and the high is 2 hr at 75 lumens. What would it take to modify the headlamp to obtain a low of about 5 lm and a run time of about 25 hr? Is that modification plausible? For my purposes, the low is all I need. I don't care if the modification loses the high and strobe settings. If it has multi settings, the headlamp would be more useful to me if the low came on first.
Second, the headlamp that comes closest to my ideal is the Black Diamond Ion. The Ion is sufficiently bright for camp chores, weighs only 1 oz, and has a nice on/off switch that is easy to operate with one hand and doesn't turn on in the backpack. The problem with this headlamp is the insufficient run time and comparatively expensive battery. The Ion takes a 6V 4SR44 silver oxide (or PX28L lithium) that has a meager capacity of about 160mAh or 0.96Wh. The headlamp has two light settings, a low (11lux @ 2m, run time of 15hr) and a high (30lux @ 2m, run time of 3hr). Black Diamond's optimistic run times are not computed the CPF common way of time to 1/2 brightness. The short run time problem is mitigated to some extent by carrying a spare battery, but a spare means more weight and the 4SR44 batteries already are more expensive than the more common types such as the CR2. I don't know why they didn't use a CR2 battery instead of the 4SR44. The CR2 is only 1 gram heavier and a couple of mm bigger (in length and circumference), but holds more than twice the watt-hours. I assume the Ion would be more difficult to modify than the Coleman Mini.
Third, it should be possible to create a headlamp from scratch, although the housing may be difficult. For example, I could start with the head of an iTP A3 Eos or A1 and run it from a CR2.
The Zebralights, Princeton Tecs, and Petzels are too heavy for my goal of 1 oz and small size. Even the Coleman Mini weighs 1.4 oz. This ultralight headlamp is for camp chores. I will carry an iTP A3 Eos and spare L92 battery for emergency night hiking.
Thanks for any feedback.
-Scott
