YuvalS
(YuvalS)
5
in addition to what Lightbringer said most driver will step down the brightness when reaching threshold temperature so unless you have really good (big and heavy) heat sink you wont be able to use 2000 (or more) Lm for more the couple of minuets.
I don't know what do you plan to use the light for but 2000Lm is overkill for most activities in close range you will blind yourself.
have a look at this light, it can run for an hour on about 1000Lm and has an option for a belt battery clip but it defiantly not budget
https://www.scurion.ch/jm19/en/lamps-en-eg/model-overview/scurion-1500-en-gb.html