Lumens go from ~0.3 at the low end to … um, direct drive at the high end. It has four emitters and a FET and a 21700 cell, so it should be able to pretty much max out four of whatever emitter it’s using. So, for 219B that’s probably a maximum of 2000-2400 lm. For XP-L HI it probably goes up to ~4500 lm or maybe even higher.
Of course, it won’t stay at that level for long… too much heat.
I wouldn’t recommend running it on turbo for long. The 219B emitters have higher Vf than 219C, so they won’t allow as much current to pass… but they also can’t stand anywhere near as much current. So I’m not really sure what to expect.
It might be a good idea to artificially lower the FET power on the 219B version, but it’ll require some testing to figure out if that’s necessary… and I’m not really set up for that kind of testing.
With most direct-drive lights, the emitters and batteries are chosen so the battery’s voltage sag and the emitter’s Vf curve will intersect at a safe point. But when using stronger cells or weaker emitters or lower-Vf emitters, things get tricky.
5000 lumens? Wow! That’s quite a powerhouse on your forehead. I hope all the mass in the head soaks up a lot of heat.
I’d bet that a few of my night mountain biking friends would appreciate that kind of power. They ride year-round. It would be great in the winter with the cold keeping the light from stepping down too quickly.
If you’re looking for a right angle light, this one looks to be top of the heap. Even without the HI leds, 2500 lumens is nothing to sneeze at.