I purchased my first minimag mod (BB500 sandwich) back in Nov. 02 and used alkalines. The alkies gave me about 75 minutes of runtime and I used the light for a bicycle helmet light. A couple of months go by and I realize I am burning through quite a few 18-packs of AA batteries. I then realize my butt is going to Iraq in early 03. No problem, drag along over 100 alkalines and I'll be set.
As soon as I got back from the desert I purchased a AccuManager 20 charger and eight Powerex 2200mAH cells and have not looked back. It really bites to use up alkalines as not to waste them so I was not quite sure the remaining runtime. When in Iraq, I could not buy extra batteries but I did have access to power to feed a charger.
Returned to Iraq in late 04 and brought along an 18 pack of alkalines and two dozen 2200 & 2300mAH cells. My EDC minimag BB500 went through 48 sets of rechargables, my shortwave radio, powered speakers, camera and other things went through about 20 sets. My buddy used 8 of my cells and recharged them twice a week. It would of taken HUNDREDS of AA alkalines to keep everything running for those 149 days (yes, I kept count) This time of could of purchased AA cells but why go through the hassle and expense? The rechargables last longer, I know how much life is left in them, no need to find more disposables and oh yeah, it actually saved me money. My buddy purchased a battery charger/NiMH batteries when he got back.
Then the MillerMods 1.7 watt L1P became my bicycle helmet light, it pulls 1.7 amps from the single AA cell so it is either lithium or NiMH batteries. Why waste money on primaries when you can waste money on new flashlights? I've been using chargers for 3.5 years and now am a "charger-holic" Have another charger that will work with 12V DC, 110V and 220/240V with adapters and a battery analyzer to keep all the cells balanced. My family uses NiMH for MP3 players, cameras and other things. They are wondering when I am going to get some Eneloops so everything will run on rechargables... alkalines are a pain in the butt.
With the high output, variable output single AA/AAA lights running Cree LEDs arriving, alkalines won't feed them very long at high outputs. Rechargables will and with the low self-discharge Eneloops available, there is just pure downsides to using alkalines. I still use lithium AA/AAA cells for my bicycle red LED flashers though, they perform better in freezing temperatures and the higher voltage keeps them bright.
The downer with RCR123 lithium-ions is, when they are gone...they are gone! I only use them with my Fire~FlyIII and check the voltage once a week and recharge when the resting voltage drops below 3.7V. Once a decent single AAA Cree light with multiple levels arrives, it gets kick off my keychain so I need not worry about that. I'll snuggle up to an Eneloop AAA to feed the EDC keychain light.
Not sure what to do with the remaining 10 CR123A cells, probably take them with me to Iraq and trade things for them.
Now to see if I can get a solar panel for my 12V charger