I was comparing runtime numbers of headlamps. The black diamond spot says max runtime of 25 hours at 300 lumens and 180 hrs on low. This is with 3 aaa batteries. This is way longer than ZL 18650 lights. Does this sound right?
That brand is notorious for their abuse of the ANSI flashlight specification standard. The standard defines runtime as the time until output drops to 10% of the initial value. They drop the output very quickly to extend the runtime as defined by ANSI.
Given that the standard was written mostly by flashlight manufacturers it’s more a standard way to fool customers rather than an useful standard.
It’s worse than that. Black Diamond doesn’t use the FL1 standard in its product ratings and instead measures until the light turns off or some such. What’s especially damning about that is Black Diamond was on the FL1 committee.
It would appear they’ve recently gotten better about this, splitting runtimes on their current product pages into a more reasonable claim, plus a low-output reserve. A Zebralight will also run at low output for quite some time when near-dead. The new Spot’s claim of 325lm for 4 hours on 3xAAA is still unrealistic, as they’d need an efficiency of 333 lm/W to make 1000 lumen-hours on 3 watt-hours of batteries.
The Zebralight H600Fd, on the other hand claims 296lm for 5.3 hours. This only requires 130 lm/W on a 12 Wh 18650 to have perfectly flat output, and Zebralights usually do have flat output unless they’re overheated or near-dead. This is a believable number.
Figured as such , thank you. When in doubt ask here .
Most runtime numbers mean nothing to me anymore. Unless the light is fully regulated at a particular setting, the runtime doesn’t mean anything.
The ANSI FL1 standard is being utilized in a very misleading way, so most manufacturers claim high lumens and long runtimes, but the reality is that the high output is rarely sustainable, and the light output will drop significantly over a short period of time.
The relatively new Biolite 330 headlamp claims 330 lumens, and after I tested it, it drops down to about 30% of its max output after a few minutes. So really you are buying a light thinking its 330 lumens but in reality its actually about 120 lumens, with a temporary misleading boost to 330. Its a nasty marketing game and looking forward to change.
Zebralight non PID modes will give a better idea of how long a battery will last at fixed regulated output with a specific battery. Unless the light uses new technology, or a larger battery, any runtimes quoted exceedingly higher than this are most likely ‘false’ and taking advantage of the ANSI FL1 standard.
The highest efficiency I’ve seen in a flashlight was the Thrunite TC20’s medium mode at 183 lm/W. That light does have flat regulation in that mode. It’s a safe assumption that numbers a lot higher than that are somehow misleading. Always look for graphs. Some manufacturers (notably Fenix) provide them, but independent reviewers are more trustworthy (bias warning: I am an independent reviewer).