Thanks again for the info.
I bought a couple of these http://www.batteryjunction.com/ultrafire-18650.html to play with. Anybody have any experience with using them or know if they are reliable and safe? Some of the brands I looked at were close to $22US so if these $7.95 batteries perform and are reliable, the price is well within the cost parameter for the project. They also incorporate the button top so they are easily replaceable.
In general, no they are not reliable. They may work according to spec, they may not. One batch may perform differently to another batch. They may wear out and stop performing after relatively few cycles. It is hard to know exactly what to expect from any individual cell in your hand.
The trouble is those batteries do not have a pedigree. You cannot trace them back to an original manufacturer, with a known quality standard and a proper datasheet describing their performance. Buying them is a bit of a lottery. (Incidentally you can probably get Ultrafire brand cells direct from China for about $4 each. That low price should give you an indication of the expected quality.)
In contrast, the other batteries I mentioned from AW, Redilast or Callie's Kustoms are first quality cells from a manufacturer like Panasonic, made in Japan with a datasheet and a predictable performance.
If I wanted a battery I could trust, I wouldn't want to go near any of the Ultrafire, Trustfire or similar brands of cell.