I have encountered strange results in burn time of testing some AA Alkaline batteries. I bought some Sunbeam batteries from the local $ store. I used three different lights on high mode. Here are the lights;
Tank TK 566, Acebeam L10, and a Streamlight Pro Tac 2 AA.
I normally have found that alkalines in such lights on high run from 3 ½ hours to as much as 5 hours. However, this test left me confused, and if I had only used one light I would not believe the results. Here are the results using the Sunbeam alkalines.
L 10 - 10hr 27min ,
Tank 566- 10hr 28min,
Streamlight –10hr 04min.
I tried the L 10 again, but only got 4hr 31min.
However, I decided to see what another test would reveal. I used a Sipik I mode, and a Tank TK 566. Here are the run times.
Tank TK 566 11hr 25min
Sipik SK68 Clone 1 mode 17hr 25min
Since I have no instruments to measure light, I compared the light to an ARC AAA which I think is 5.5 Lm. When it went below that point for a short time I terminated the test. Your own criterion as to where it should be terminated could differ.
I hesitated to post these figures, and only after a second test did I decide to do so.
It seems that the lights reach some level from 5-8 lm and evidently do not draw much current so last a very long time. However, I have not found any other battery that matches these run times.
When terminated the lights would not turn on, but after resting both lights would turn on and reach hi mode. Voltages were 1.19 and 1.21 volts. I believe they would power the lights for maybe several hours in a moon mode. The 566 ran through the three modes, and the mid mode might be useful for a couple of hours or so.
In considering camping trips and long overnight hikes the prevailing thought is to carry several lights and a lot of nimh or li-on batteries. Unless one just wants to play with the lights it makes more sense to use these alkaline batteries. If an eneloop runs about 2hrs it requires 4-5 to equal one alkaline that burns 10 hours.
Obviously your determination as to level that is useful will vary.
If you say these results do not make sense, I agree. But I intend to buy a few more of the 25 cent batteries.
Jerry