I am looking to upgrade my old quark and are looking at the lumen performance of all these fancy new emitters. However, it seems that all these small lights can max. candle somewhere between 350 and 400 lumens in constant mode (more then 10 min.). Can we expect more, or is that simply the thermal limitation for such small lights?
Yes, that's starting to push the limits of a 2xAA light. I recently got an Armytek Prime A2 (warm), and measure it about about 460 lumens (25% brighter than I measure the XML2 Quark 2xAA light before its 3 minute step-down). The cool white version of the Prime A2 should be about 500 lumens.
Anyway, the Armytek has thermal step-down (only steps down if it gets too hot), and I ran it for about 30 minutes on maximum, tailstanding in a warm room, and it never stepped down. It was hot to the touch, but no hotter than my Quark XPG2 2xAA light gets, and it's only about 230 lumens (constant with no step-down).
The Armytek is slightly larger, with more mass, so perhaps it's better at dissipating heat. It also seems more efficient on maximum than my Quarks, so produces less heat. Whatever the case, 4sevens seems more timid at running hot than some other brands, probably because the Quark XML2 uses a simple timed step-down so has to account for worst-case.
Overall, around 500 lumens seems to be the limit for a 2xAA light, without utilizing some kind of step-down. Less for a 1xAA light.
