Just tried two eneloops in my 9P w/ the 219 triple - it produced about 10 lumens of light. Very interesting...
I finally tried two eneloops myself (Nicha triple). I used the 123 size extension and needed a magnet and a nut as spacers to make contact. These are the 2000mah version with full charge 2.8V in my Solarforce L2P, L2-S8 tail.
I got more lumens than you. I see around 35-40 lumens. (as we read in an earlier post the tail switch can affect output).
My single CR123 (3.2V) cell gave around 75 lumens.
So I tried 3 of these eneloops and get full output.... very bright. I had to use the 18650 extension and couldn't tighten it or the tail cap all the way due to the length of the 3 cells. I measured 4.2 volts.
There is some more data to chew on, guys and gals.
I like the length of my light with a single 18650 or with the shorter extension, but the double 18650 is a bit long for me. It is less stable when tail standing too.
I think I might order some 18500 x2 protected button top cells and get the benefit of full regulated output with the shorter extension tube. (Keepower 1700mah look good). I can pop in two AA cells if I want lower lumens, but I would likely just use a different light with multi-modes!. L3 Illumination L10 Nicha.
The single 18650 config is good if diminishing output is OK. The double 18650 is fine for extended run times with regulation.
Yep, a 3 mode driver would be nice here.