Also, batteries eventually wear out. To keep battery costs low, you need rechargeable batteries and a battery charger. An AC adapter is also useful because it lets you plug the camera into the wall when the batteries run out. It limits your range, but lets you keep shooting, and it's very useful when playing back images on the TV set or uploading images to the computer. They are also more environmentally friendly because they are made from non-toxic metals.
NiCad batteries are the most widely used type of rechargeable battery.
They charge quickly, last approximately 700 charge and discharge cycles, and perform well in low temperatures. Their only drawback is their memory problem that will eventually reduce their total available charge. Lithium Ion batteries last about 2 hours, twice as long as NiMH batteries of equal size. They also don't lose their charge as quickly while in storage. They have the same life expectancy as NiMH batteries, about 400 charge and discharge cycles, and do not suffer from memory effect.