All digital cameras and some camera accessories rely on batteries. Some accessories like flashguns may use regular AA batteries, but almost all cameras now use rechargeable lithium ion cells which have a longer life and deliver a more consistent power output between charges.
AA batteries, as used in some flashguns and older battery grips, come in single-use disposable types and rechargeable batteries. Amongst disposable batteries, alkaline batteries are the cheapest and most widely available but don’t always give a long or reliable power deliver. You can get disposable lithium cells which last a lot longer, but these are expensive and hard to find.
Instead, almost all photographers use rechargeable AA batteries. Older NiCad batteries perform pretty poorly newer and NiMH batteries have more or less taken over. Even these vary in performance. Standard NiMH batteries suffer from memory effects and quickly lose charge in storage. Newer, more advanced types, such as the Eneloop cells developed by Sanyo/Panasonic lose their charge much more slowly and are worth seeking out.
Lithium ion batteries
Lithium ion batteries are the most common battery type, offering long battery life and consistent power output between charges. The lithium ion technology means batteries can also be made in all sorts of odd shapes and sizes to fit anything from a professional DSLR to an action cam.
The bigger the battery, the higher its capacity and the longer the battery life between charges. Battery capacity is rated in milliamp hours (mAh) but since different devices have different power requirements it’s more useful to use the device’s rated battery life, as quoted by the maker. Battery life is often checked and verified by the CIPA standards body.
Battery life is an important specification for cameras, especially compact or action cameras or mirrorless cameras; compact cameras have small bodies and hence small batteries, mirrorless cameras use more power than similar-sized DSLRs.
Sports, fashion and commercial photographers will often use a battery grip to extend the camera’s battery life out in the field. The battery grip may take a larger lithium ion cell to supplement the one in the camera, a couple more cells of the same type or (in older grips, mainly) up to 6 AA batteries.
Battery chargers and power
Most cameras and other devices that use lithium ion batteries will come with a battery charger. Typically, this is a separate charging block that you plug into a wall socket, and you remove the battery from the camera to charge it.
Increasingly, many cameras now offer in-camera charging, where you plug a charging cable directly into the camera’s USB port and leave the battery in place while it charges.
USB charging is actually a very useful feature because as long as you have a cable that fits your camera you can charge it up using any USB charger, laptop computer or airport/hotel USB charger.
It also means you can use a portable power bank to recharge your camera. This is ideal for times when you’re away from a mains power supply all day and don’t have a spare battery.