To keep this post, short and sweet, we will restrict the topic to high quality/high performance, NiMH/NiZn AA rechargeable batteries, with 2200mAh and more. This will reduce confusion, and focus the discussion on items worth mentioning.
As photographers, we need to power flashes, and they consume a lot of "juice". Most of us have realized the impact of discarding such a large quantity of standard Alkaline batteries, and have made the switch to using rechargeables.
But, what company offers the best product, when it comes down to...
1. Quality (Construction)
2. Power (mAh)
3. Duration (Qty of charging cycles)
4. Self-discharge rates (Percentage of power after period of time without use)?
5. Cost-effectiveness (Value)
Here are the companies that have made the cut towards being considered the industries best rechargeable AA battery, readily available in our location (North America).
1. Duracell PowerPix NiZn (1.5V, 2450mAh)
2. Powerex IMEDION AA NiMH Batteries (1.2V, 2400mAh)
3. Eneloop XX (1.2V, 2400mAh)
4. PowerGenix PGX-4AAZiNc (1.6v, 2500mAh)
In addition to the quantity of full-power burst in a Canon 600EX flash head, we also found data in form of a Ragone Plot, of various battery cells, demonstrating that there's a considerable difference in performance between each type.
The Eneloop & Imedion were the top 2 batteries, but what was the determining factor was the number of cycle times rated by Imedion (number of times that they can be recharged), as well and the fact that they can retain a higher % of charge, after being inactive for several months.
Going to rechargeable battery cells, makes a whole lot-of-sense, whatever make you decide on using. It's both Eco-friendly, and in very little time... cost-efficient!
On a last note... All of the above-mentioned fabricators offer a decent quality charger, but they are limited to 4 cells. I met a photographer from the UK at an event last summer, that boasted the VAPEX VTE-8000 8-cell charger. I had a hard time locating one, but after having used it for over 8 months now, I can honestly say it was worth the trouble. It is fast, reliable, accurate, and it's small size makes it very convenient for travel. It charges both AA & AAA cells.