Rechargeable Trail Headlamp

Details

A headlamp on a single 18650 lithium cell you can take out and replace, charged over USB-C with the cell in place. Lumen inflation in this category is endemic and it works because the word lumen has no test attached to it in ordinary use. A lamp claiming 1,000 lumens is usually quoting the LED emitter's rating on a datasheet at a current the lamp never delivers, measured before any lens, and holding it for about four seconds. The standard that fixes this is ANSI FL1, which says: measure the light 30 seconds after switch-on, and call the runtime the time until output falls to ten percent of that 30-second figure. Every number on this page is that measurement. So, honestly: 350 lumens is the FL1 figure at 30 seconds, and it does not stay there. The lamp holds 350 for about three minutes, steps to 300 and holds that for the first hour, then runs 150 until four hours, then drops to a 15 lumen reserve that lasts about another twenty. That is the driver protecting the LED from heat and the cell from collapse, and it is what every regulated lamp does. The difference is printing it. The arithmetic is there to check. The cell is 3,400 mAh at 3.6 volts nominal, which is 12.2 watt-hours. The high-mode ladder above draws about 11.8 watt-hours end to end, which is the whole cell less the margin a protection circuit keeps back.

• 350 lumens at 30 seconds to ANSI FL1, with the stepdown ladder printed
• 4 hours on high to the FL1 ten percent point, then a 15 lumen reserve for about 20 more
• Medium 90 lumens for 11 hours, low 15 lumens for 60 hours, red 3 lumens for 100 hours
• Beam 90 m to the FL1 quarter-lux point, from about 2,000 candela peak
• One 18650 cell, 3,400 mAh, user replaceable, any protected standard cell fits
• Cell to IS 16046 Part 2, the BIS standard for portable sealed lithium cells
• USB-C charging with the cell in place, 3 hours from empty
• IPX6 to IEC 60529, adopted in India as IS 12063. Heavy rain and jets, not immersion
• Metal tilt pin, not a plastic ratchet tooth that strips, and a washable removable strap
• No sealed-in battery, no proprietary cable, no emitter-datasheet lumen figure
• The low mode computes to 73 hours off this cell and measures 60, because driver overhead is a real load at 15 lumens. The measured figure is the one printed.