Oh wow. Thanks. My brain is about to explode looking at that link though. On quick glance, I noticed that the rcr123 is now named 16340? So that leaves two possible battery choices, the IMR 16340
http://www.cpfmarketplace.com/mp/showthread.php?p=2272984#post2272984 or the LiFePO4 R123
http://www.cpfmarketplace.com/mp/showthread.php?t=125353 , although the latter I'm guessing is not a Li Ion battery. Which is better?
I noticed that I couldn't find anymore AW RCR123. Are these discontinued in favor of a better/newer battery?
The AW RCR123 is still available - it is the
Protected R123A ( 750 mAH ) which goes for $6 each.
This should be fine for your purposes - and for most general use. If you don't want to be potentially confused by the various types of cells, don't read on. However... if you want to...
Regarding the different types - they are all Lithium Ion cells. However, they make use of different chemistries for their cathodes (you can look up lithium ion on wikipedia).
The AW RCR123 is cobalt based, the IMR16340 is manganese based, and the LiFePO4 is iron phosphate based.
As for the differences between them:
Safety: The cobalt RCR is the unsafest (Can "rapidly vent with flame"). IMR is safer, and LiFePO4 is the safest.
Protection: As the cobalt cells are unsafe, protection circuits are added - in the case of AW's cells - hence your Protected R123A. The safer IMR cells and safe LiFePO4 cells don't have protection circuits. Protection circuits protect against overcharging/overdischarging/overcurrent but normally make the cells slightly larger.
Voltage: The RCR (Cobalt) and IMR cells both ~ 3.7V, although the IMR cells are generally a bit higher. Meanwhile, the LiFePO4 cells work at ~ 3.2V. As such, the LiFePO4 needs a different charger from the RCR/IMR cells
Capacity/Energy: The LiFePO4s have the least amount of energy (500mAh*3.2V = 1.6Wh), while the IMR has slightly more (550mAh*3.7V = 2Wh), while the RCR (Cobalt) has the most (It's advertised 750mAh, although in reality it's probably about 650mAh*3.7V = 2.4Wh).
However, at high discharge rates, the cobalt RCR looses a lot of capacity, and the IMR maintains higher capacity.
Discharge Rate: The cobalt cells can only be used up to ~ 1.4Amps discharge, while the IMR cells can be discharged up to 5Amps. I wouldn't use the LiFePO4s > 1.5Amps, although they can handle high loads such as 5Amps with very little capacity.
Hmm.. I gotta go. Hopefully that's enough information.