Hmmm. I don’t think the reason it dies on 14500 is due to heat from no stepdown. I only put 14500 in to do a ceiling bounce test and it died literally within a few seconds. While it worked, it was much brighter on 14500 than AA though so it would be a great EDC with 14500 if it works reliably.
I posted my results here so you can compare it with other AA lights too.