If you use a lot of flash in your photography, you no doubt go through batteries like a fiend. In my experience, rechargeable batteries are definitely the way to go, but I’ve heard a lot of photographers complain about recycle time. I’ve sworn by (and continue to swear by) Sanyo Eneloop batteries for my flashes (AA) and RadioPopper wireless triggers (AAA). Sanyo recently released a new high capacity version of these extremely popular batteries (especially among photographers), and while it may seem like a good idea to upgrade in order to increase the recycle time of your flashes, it does, as one would assume, come at a cost.
I might invest in a couple sets of Eneloop XX’s for shooting in situations like bright sunlight where full power is often a necessity, but for most shooting situations where less than 1/4 power already produces fast recycles, I see little need to sacrifice lifespan, durability and $$$.
1) If you have a lot of batteries and have a hard time keeping track of which ones are charged and which are not, consider picking up a couple of small, different coloured camera bags (point & shoot style). You can often find last years bags in discount bins. Also consider getting a green one to indicate charged batteries and a red or black one for discharged batteries.
2) I also carry a compact battery tester in case I need to double check the charge on my batteries. You can find these on eBay or at your local hardware store and average about $5.
(Note: Ironically, as I was writing this, I took a break to check facebook and SLR Lounge had just posted an article comparing the flash recycle times of many of the top rechargables batteries. Take a look at number one. Go figure. http://www.slrlounge.com/best-rechargeable-aa-batteries-flash-photography)