Create a list of all the lights you have [I know this could be tedious], jot down which flashlights uses which batteries and where your flashlight is placed in the house
ex: {(In kitchen) Surefire A2-HA-WH [Square] [long clip: A31798 , Flat bezel, THC3 LED][Surefire CR123A 06-2012, replaced 01132009]}
I use a wordpad file on my desktop to keep track of 45 flashlights around the house.
When your charging battery packs thats alright, but when your charging cells separately take note of cell position and don't mix the batch]
Record charging conditions
ex: {(In Garage) [On Santa Fe] 3D Mag85 [D3012839206, Enelooped][Last charged 02122009][Batch: N2][Mdocod holder: BH2]}
N2 is written on all the batteries in the holder marked BH2...any time cells gets replaced or the light leaves the garage I would immediately update the info, much like balancing your checkbook, you get used to it after awhile
As for batteries
Theres another notepad for batteries
heres the current log, most of its contents are self explanatory...one of these days I'm gonna convert it to excel
[CR123A][Log: Jan 2009]
12x Energizer [box][Batch: 0608A][Location: Home-Tray 3]
2x Energizer [Jil-tube][Batch: 0608A][Location: BOB]
2x Energizer [Jil-tube][Batch: 0608A][Location: Office]
4x Surefire [SC3][Batch: 01-2016][Location: Office]
[AW][Log: Dec 2008]
2x AW14500 [5 cycle][Batch: 1R14500][Condition: charged][DMM: 4V OCD][Location: Home-Tray 2][Log: 02142009]
2x RCR123A [6 cycle][Batch: 2R123][Condition: used][DMM: n/a][Location: Surefire E2e + LF-EO-E2R (Short Clip: E2e body A274881)][Log: 02142009]
1x 17670 [9 cycle][Batch: 1R167][Condition: used][DMM: 3.9V OCD][Location: Home-Desk][Log: 02142009]
3x17670 [6 cycle][Batch: 2R167][Condition: charged][DMM: n/a][Location: Surefire M6 + 3x17670 + 1185 (M6 Magnumlight A004110)][Log: 02102009]
NiMH[Log: Jan 2009]
6x Eneloop AA [6 cycle][Batch N1][Condition: charged][Location: Mag Instruments 2D [ROP-HI](D2030858468)][Log: 02142009]
9x Eneloop AA [6 cycle][Batch N2][Condition: charged][Location: (3D Mag85) (D3012839206)][Log: 02142009]
9x Eneloop AA [6 cycle][Batch N3][Condition: charged][Location: (3D Mag85) (D3032933836)][Log: 02142009]
1x Eneloop AA [3 cycle][Batch N4][Condition: charged][Location: Zebralite H50][Log: 11252008]
4x Eneloop AA [2 cycle][Batch N5][Condition: charged][Location: Kitchen Osram golden dragon lantern][Log: 01212009]
4x Eneloop AA [2 cycle][Batch N6][Condition: charged][Location: Mstr Bed Osram golden dragon lantern][Log: 01212009]
...
it goes on to include eneloop AAA, elite 1600 AA, AG3, LR44, CR2016, CR2023, Duracell AA, Duracell AAA, N, C, D, 6V lantern, L91, L92
its a pretty big file, and can get chaotic...since it includes the information on every fauxton in the house. But once you build your own library its easy to update it, I look through it everyday, before I log on to CPF, and take an inventory every month. [hey, I warned you about the tedious part :nana:]