That makes sense. Rereading the first page, it seems a little clearer. I can live with 6v max.
I did, indeed mean 35 milliamps (.035 amps). Is that too low to power these emitters? Maybe I misunderstand, but when you say "very very dim light" I hear "less than 1/2 lumen," which is dimmer than I want. I was thinking I could hit 10-20 lumens at that drive level (which is more of a "moderate" light level in my mind).
What drive level do you use for the "Low" setting on your multi-mode modules? 50mA? 75mA? Do I need to be thinking of something like that as a minimum drive level? If I used a different emitter (like an XP-G, maybe?) would that give me a lower useful drive level?
I was thinking that the XM-L is rated at 100lumens/watt, so .1 or .2 watts would give me 10-20 lumens. Maybe it doesn't work that way at the lower drive levels, though?
I was also calculating that 35mA would consume 1400mAH in 40 minutes of runtime--so 36 hours or more of regulated runtime might be possible with lithium primaries.
I'm open to suggestions! I'm looking for a single level, low output (not ridiculously low, but usefully low--like the low on a Surefire L1 --or the Lx2 low at the most) unit that would maximize runtime on 2 primary cells.