What is the difference between the available AA battery chemistries?
AA batteries are available in four basic varieties:
Nickel-Metal Hydride (NiMH)
Photo Lithium (Li-FeS2)
Alkaline and photo lithium are non-rechargeable, while NiMH and NiCad are rechargeable. Each has advantages and disadvantages.
Non-Rechargeable vs. Rechargeable:
Rechargeable batteries are desirable from an environmental standpoint because they are reusable.
Self-discharge refers to the fact that batteries lose energy when unused and even when not in a camera or other device.
Rechargeable batteries tend to have relatively high self-discharge rates, approximately 1-2% per day for nickel-based batteries.
Non-rechargeable batteries generally have very long shelf lives and extremely slow self-discharge rates.
This makes non-rechargeable batteries a better choice for infrequent usage.
Non-rechargeable batteries are available fully charged in stores all over the world, which makes them a convenient choice for travelers or customers who have dead rechargeable batteries and no time to recharge.
Photo Lithium Batteries (Li-FeS2) (non-rechargeable):
Photo lithium batteries will yield the longest battery life of any AA battery, surpassing NiMH by 50-100% and surpassing alkaline by 100-500%, depending on the load.
While they are more expensive than alkaline batteries, their additional energy capacity makes the cost the same or less per shot than alkaline batteries.
Nickel-Metal Hydride Batteries (NiMH) (rechargeable):
NiMH batteries are the lowest cost overall solution for users that take a lot of pictures (more than the equivalent of a roll of film per month) or use a lot of high-power features.
The largest disadvantage to NiMH batteries is their fast self-discharge rate of 1-2% per day whether the batteries are in a camera or not.
NOTE: NiMH batteries need to be completely charged and discharged a few times when new to achieve their full capacity.
Rechargeable batteries will eventually fail. If you have been getting acceptable battery life and then see a decrease in life, either quickly or slowly over time, a worn-out battery may be the cause. Storing or charging the batteries in high temperature conditions will accelerate this potential failure.
Alkaline Batteries (non-rechargeable):
Although the cheapest and easiest to find, alkaline batteries yield the worst performance of all the chemistries in a digital camera. They lose capacity at high power drains and at low temperatures. Skiers and other winter outdoor enthusiasts may find them unsatisfactory.
Alkaline batteries are frequently available in two types:
High drain (ultra, titanium, maximum etc.)
The high drain versions are a premium product designed to operate better under heavy loads than the standard product. However, there is a trend of major brands to increase the performance of their standard battery to b