From @koef3 reviews of the 2 LEDS:
SBT90.2 here: 9 mm2, luminance @ 30A = 232.9 cd/mm2
SFT-25R here: 2.2 mm2, luminance @ 8.2A = 215 cd/mm2
Max luminance within range, so how does my humble1600lm SFT-25R M21E sneaks into this land of giants, 1km throwers with 5000lm SBT90.2 LEDs? AND a smaller host with smaller reflector? I really did not expect this when I ordered the light.
The answer is found in the tortoise and hare “side-effect” of ANSI throw spec: throw is calculated at 30 sec, not at turn-on. I will check the numbers but I believe what happens is Wurkkos SBT90.2 starts at nuclear FET direct-drive brightness, but within 30 seconds is forced into step-down by the tremendous heat generated. SFT-25R starts with less brightness, hence stays cool, hence no step-down. The SBT90.2 rabbit ends up tied with SFT-25R tortoise at 30 seconds, both with fantastic AND similar calculated throw around 1 kilometer.
