Heres the thought, throw distance is limited by beam direction and lumen scattering/absorption by air.
Beam direction would be unchanged, but a PWM light is running at full power for fractions of a second, so a 3A regulated XM-L is theoretically putting out 1000 lumens. At 50% output its putting out 1000 lumens for half of every second switched at high frequency.
So the throw should be scattered to same degree and absorbed at the same rate but more lumens are in the beam going further.
The difference may be slight or it may be noticeable
Thoughts?
PWM isn’t usually used for high mode is it?
As far as I can tell however it shouldn’t make a difference in throw. The output is the same. It’s just whether or not it is constant or not.
The same percentage would be scattered at constant or any pwm frequency. Throw is a function more of focus than output but with any given focus more output should equal more throw. Because of led efficiency I would guess that an XML at 1.5A constant would have slightly more output than one at 3A 50% pwm but that is just a guess on my part. Unless you are ionizing the air with a very high power laser you are unlikely to generate enough heat to cause atmospheric effects with a flashlight. Bsometer is pegging.
In fact, quite the opposite. Most LEDs are more efficient at lower currents…
An LED driven constant current at 1.5amps will put out more lumens than the same led driven at 3amps 50% of the time. Because of this, a constant current driver will out throw a PWM’ed driver (in most cases anyway).
They do, however, become equal in high mode, when there usually is no PWM - they’re both running in either constant current or direct drive. Anything less than full brightness though, and the above will be true - current regulated will be brighter (and hence throw further) than PWM’d for the same amount of heat/power.
PPtk