I have ended up with three A2 lights (2 4-flat bodies and 1 ‘round’ body). I also managed to snag two used A2 strion kits and am looking forward to getting the ‘onion’ led rings when they come out. The last thing to do to facilitate using them more often is getting a lithium rechargeable set-up. I have been shamelessly exploiting AA Nimhs whenever possible, sometimes using extenders with various other set-ups (or M*glites), and I have been a little intimidated by the known hazards of lithium rechargeables, but I really want to start using the A2 (amongst others) more capriciously, so it’s time to take the plunge.
I know that this issue has been raised many times before, but I am struggling with it for the first time. I have spent a number of hours reading hundreds of posts over the last few days.
I really, really, want to use ‘protected’ rechargeable cells (don’t want to have to deal with a DMM for now). Runtime is less of a priority. It seems the challenge is finding protected cells that fit an A2 body.
This is what I came up with:
It’s a Tenergy ‘3-3.2 volt’ (-3.6v) RCR123a 900 mAh ‘yellow label’ cell. It has PCB protection. Its external diameter is 16.5 mm, or approximately 0.649 606 299 21 inches. On one of the many A2 posts, someone listed the internal diameter of their ‘4-flats’ A2 as being 0.653 inches, and the round-bodies are supposed to be a little bigger. This cell’s height is 34mm, or 1/2mm shorter than the dimensions that I have seen listed for one brand of primary CR123a, so it’s not too long.
About the only thing that concerns me is the Battery Junction page warning against using these in incan SureFires, although it looks like some people on cpf are using cells that can be as high as 4.2v fresh off the charger, saying that any 2xCR123A SF led light can take as high as 9 volts(!)
[ http://www.candlepowerforums.com/vb/showthread.php?t=205723 , post# 3] , but the BJ product page specifically warns that SF voltage regulation takes ~12 milliseconds to kick in. Is that going to be a problem with lithium rechargeables?
I’ve only seen one post mentioning this cell as their choice in an A2, and I’m wondering why.
To recap, here are my main questions:
#1 – Will this Tenergy ‘yellow label’ work safely in my A2?
#2 – If this cell is appropriate, what is the best possible ‘smart charger’ for this type of cell (not including ‘hobby chargers’)? I get the impression that the highly-regarded Pila IBC will NOT work for this type of cell. If this cell is appropriate, and there are no clear-cut top choices amongst others more experienced than I, I would probably go with the somewhat inexpensive ‘smart charger’ listed at the bottom of the BJ product page for this cell.
#3 – Can I safely use this same cell in my E2L, E2DL, and U2?
#4 – What sort of decrease in brightness might I expect using 2 of these with a SF P91 lamp?
Thank you very much for reading this, and sharing your expertise.