Batteries can certainly be a challenge to some people, and can be frustrating when one encounters a drained battery or even worse yet a leaky battery. Capacity, voltage, discharge, as well as how you are using the battery can all be things to consider when choosing which batteries to purchase. Double AA or even triple AAA are certainly the most common types of batteries used in most electronics. Yet, just because a battery may say 1.5 volts, all batteries will not typically perform the same.
Carbon-Zinc: 400-1700 mAh
Alkaline: 2000 -2500 mAh
Lithium: 3000 mAh
Carbon-zinc batteries are slowly becoming more difficult to find, but certainly are the least expensive. They often deliver the least amount of energy and are typically not useful in the photographic world for producing a consistent reliable results. The energy needed for most speedlights is considerable especially if operating in a large darkened area. Also, they do not perform well in cold temperatures.
Alkaline Batteries (potassium hydroxide) are common and typically moderately priced. They typically have a long shelf life (5 yrs +) and can power photographic devices under moderate use. They typically are long lasting especially in photographic triggers that only require a small amount of energy to initiate signal. These batteries when used in speedlights will have a short life span (weeks) especially in large darkened areas. Alkaline batteries also have a tendency to leak due to pressure build up within the batteries and release of hydrogen gas. They should never be stored inside any expensive piece of electronic equipment.
Lithium batteries offer the higher energy density of either of the two battery types above. They often have a shelf life of over 10 years and perform well in a variety of temperatures. They typically will provide the most reliable and consistent results even under heavy use. Unfortunately the are very flammable and should never be thrown away in regular trash. They can also be very expensive. Larger lithium batteries are also often found in studio strobes, cameras, and other larger pieces of equipment.
What does this mean in practical terms? It could be difficult to defend a carbon-zinc battery with the energy draw of current photography equipment. Perhaps if you had lost other batteries and were at a dollar store, you may be tempted to pick up their supply of carbon batteries.
Alkaline batteries are very common, and can last several weeks or even longer in a remote that triggers strobes. They cost about 97 cents per battery as of this post so their are fairly cost effective. They are fairly durable in hot and cold climates though may not last as long as lithium batteries. When used in speedlights they have a relatively short life, especially if the speedlight is used at near full power. One can sit and wait until the speedlight is fully charged between shots, which can waste quite a bit of time and may result in missed opportunities. Almost all alkaline batteries leak after a certain point, so they should never be stored in an electronic device. A leaking 97 cent battery can easily destroy a $400.00 speedlight!
Lithium batteries are expensive (about $2 or more per AA battery). Even so, they provide more energy on demand than a alkaline and much more than a carbon battery. They tend to hold their charge longer than other batteries. When shooting a high priority subject (such as a wedding), one does not want to see battery failure. Camera batteries and strobes are often lithium for reliability purposes. In addition, lithium batteries are often rechargeable. The downside is that they are often heavy, and are flammable. Airlines may prohibit flying with larger lithium batteries and mail services may require special carriers to deliver lithium batteries.
I tend to follow these general guidelines:
Obviously there are some type of batteries such as Nicad, however I addressed the more common batteries within this post.