Ahhh ... point taken. Thanks Doug. I'd forgetten about that article.

New calculations using Sure Fire batteries at $12 for 12 ($1.75 each):

Fenix TK10, High 225 lux: 1.5 hrs, 2 CR123 ==> $2.33/hr
Fenix TK10, Low 60 lux: 10 hrs, 2 CR123 ==> $0.35/hr
P-Tech EOS, High 185 lux: 60 hrs, 3 AAA ==> $0.65/hr
P-Tech EOS, Medium ?? lux: 60 hrs, 3 AAA ==> $0.14/hr
P-Tech EOS, Low 18.5 lux: 60 hrs, 3 AAA ==> $0.03/hr
SL ProPoly 4AA 40 lux: 4 hrs, 4 AA ==> $0.43/hr

The CR123's still reasonably cost effective ... so long as I limit the high power usage. Plus I think they provide a much better flashlight form (length & width of tube).

Ken K.