This is widely accepted standard for flashlights and headlamps, which defines runtime as time until the light output drops to 10% of its original value (value measured 30 seconds after turning the light on). That means, that light which shines 1000lm in the beginning and after two hours just 100 lumens has got same runtime as light which constantly shine 1000lm. This extreme case shows how it doesnt tell true runtimes, which could be usable for the user. Difference between 100lm and 1000lm is remarkable. This standard favors unregulated lights, whose light output gets lower over time.
We want to tell our customers runtimes, which are true and can be normally used. With this more strict runtime specification we loose hours, minutes of runtimes.
Here is graph taken from site OutdoorGearLab, where you clearly see what its all about. Lights have got 50h runtimes, but keep their high intensity only for 1-2 hours. These are examples of cheap unregulated lights, they lack constant brightness regulation.
We specify runtime as a time until the light output drops to 70% of its original value. Runtimes are real, true and tell minimum time of constant light. After the battery is not able to supply enough power, headlamp always switches to the lower mode. Runtimes in lower modes can range in hours so you can safely complete your activity.
All our headlamps have 5 constant white modes and switches the same. Intensities of these 5 modes are set so they are visible differences between all modes and there is always proper mode for your activity in terms of adequate light output and runtime. The lowest mode is usually for camping and walking with 90-180h runtimes. Higher modes have got runtimes typically 20h, 10h, 4h and 2h. 10 hour mode is useful for night racing - all 24h competitions, Rogaining, ultra runs. Highest mode is for high speed night activities like downhill riding, orienteering racing or mushing.
One of key advantages in our Lucifer headlamps are very long runtimes. All quality parts inside headlamp make this together happen, namely: great CREE leds with highest lm/W ratio, best li-ion cells from Samsung with highest true capacity, strong cabeling with low losses, connectors with low resistance, exceptionl cooling on revolutionary copper printed circuit board, ultra high efficiecnt switching covnerter. Our headlamps converts battery voltage to LED voltage with highest possible efficiency which is over 90% almost in all conditions, offen reach amazing 95-98%.