UF cells seem to be the least reliable of all cells available. I only have 2 UF cells, they were given to me free with another transaction, and one of them works correctly, the other has a bum PCB that comes and goes as it wants to.
Any significant amount of time spent browsing around here long term and you start to develop of feel for which cells do well and which don't. UF "grey/blue" cells are easily on the top of the list for cells that repeatedly fall in far-below typical capacity for their size and have a high rate of PCB failures and major cell-to-cell inconsistency. Lately I keep hearing good things about trustfire cells, but am wary of their source. AW has been with CPF on the long haul and is always wiling to stand behind his product, I just wish he would come out with some higher capacity cells to compete with new stuff from trustfire, wolf-eyes, etc. His RCR123s are some of the only protected RCR123s on the market that are really close to the true size of a CR123. Almost all other brands of RCR123 you will find out there are oversized by several mm in length and a few tenths in diameter. Yes, the alternative oversized-brands will *usually* have more tested capacity, but they won't always fit in your light. AW cells have proven to be on the higher end of reliability and safety but aren't a guarantee against failure. For the sake of comparison, my UF RCR123s, which I was told were basically un-used upon receiving, perform about as well on runtime/capacity as my AW RCR123s, however, the AW cells being compared are several years old and very heavily used. This suggests to me that these UF cells are nothing special.
There isn't an easy answer to the best option for RCR123s and a charger. It's all a tradeoff. The best li-ion charger would be the Pila IBC, but for RCR123s, it's charge rate is a little too high if that's the primary cell you plan on charging. Most of the RCR123 chargers on the market use a CC-only charing method, that ramps the voltage as high as ~4.3V before terminating the charger. While not the worst method, this certainly isn't ideal. The DSD chargers seem to be fine if you live in a place with standard 120V service, they fail on 220V. Problem with the DSD is that it's only a single channel charger, so you must make sure to always install either a single cell into the charger, or pairs that are in a similar state of charge. The DSDs charging algorithm isn't perfect either, but I would call it much healthier and safer than the charging methods found in most of the ultrafire/etc chargers.
For the cells, there is a chance of getting a dud no matter who you order from, and to get more capacity, you have to go with oversized cells that might not fit. Every brand is dramatically over-rated. The best performers tested to date are some trustfire white label.... Check out this thread:
http://www.candlepowerforums.com/vb/showthread.php?p=2532646#post2532646
Now, you'll see that the best performers were the DX8683, but guess what? Back when those tests were done, the 8683 was a trustfire cell, DX has "bait-switched" the cells being sold under that product code... gee, I wonder why? Maybe they are trying to get rid of those pesky UF cells with the higher profit margins?
-Eric
