I'll just speak in generalities as I don't actually have this light.
First Batteries.
Li-ion 16340 and 14500 (AA size) are capable of the same lumens output, probably in the 400-500 range on this light, but the 14500 has 10-15% greater capacity/runtime due to the slightly larger volume of the AA size.
Lithium primaries cr123 vs L91 (AA size) have the same watt-hrs of energy, but cr123s will have about 40% higher perceived brightness due to double the voltage and lumens which I would think will be in the 200-250 range. Despite the two batts having the same total energy, runtimes will be a bit better on the cr123 since LEDs tend to be more efficient around 3V, and lithium primaries have about 50% more total energy than the other batt chemistries.
Alkaline and NiMh batts - cheap, safe and widely available - are only available in AA size. They'll max out around 100-150 in this light, I'd say around for an hour. NiMh run high lumens longer but Alks interesting run ultra lows longer.
Next Lights
Broad voltage lights that have buck and boost drivers and can take all batteries like this, 0.9-4.2V, tend to be less efficient than than narrow voltage boost only lights like say a Fenix that I think can get up to 50% better runtimes.
Infinitely variable lights like this also have an electrical overhead drain to operated the ring, roughly equivalent to a 3 lm mode or 10ma. So for example, I think the best you'll be able to get from this light is ~ 70 hrs at a sub-lumen level while a Fenix should be able to do 70hrs at 3 lumens and a Quark or Zebralight ~ 300+ hrs at an equivalent sub-lumen level on 1xAlk. It's important to note that this electrical draw will be immaterial to higher lumen levels (ie, 100 lumens ~ 300ma).
Well, that's $0.02.. hope it helps.
