I’m the first to admit being a bit compulsive about batteries. I condition them, charge them, check them and clean their terminals when necessary. I even label them with the date they went into service. I attached a power strip to one end of a workbench and use it exclusively to feed my rechargeables. Before you yell, "Get a life!", understand that I’ve never—not even once—run out of power before I ran out of pictures.
In 1800, an Italian scientist named Alessandro Volta created an electrochemical contraption called the Voltaic Pile. It was the world’s first battery. Since then, there have been dozens of attempts to construct batteries that were smaller, longer lasting and more powerful than anything else on the market. Camera development is heavily dependent on innovations in battery technology—if you don’t have small batteries, you can’t have small cameras. And if you don’t have long-lasting batteries, digital photography can get frustrating fast.
During the 1990s, when Minolta Corporation was developing its first consumer digital camera, battery size and battery life were two of our top concerns. The camera used four AA cells, which represented more than 20% of the camera body’s volume. Performance with alkaline batteries was dismal, and rechargeable cells were much more expensive than today. In contrast, the last consumer camera Minolta produced used a lithium-ion cell that could be hidden in a matchbox.
Lithium Ion (Li-Ion) reigns supreme, particularly with D-SLR cameras. However, many compac cameras—including best-selling models from Canon and Sony—use good old AA cells. Thanks to a chemical formulation called Nickel Metal Hydride (NiMH), rechargeable AA batteries are inexpensive, long-lasting and exceptionally renewable. In the early days of 35mm SLR photography, cameras used small—button cells— to power their built-in light meters. Electronic flash units typically used AA cells or rechargeable nickel cadmium (NiCd) packs. Some early battery chemistry—including mercury, cadmium and other toxins—wasn’t landfill-friendly. Things have changed, of course, and while some cells (including Li-Ion) must be recycled, NiMH batteries are "green" and can be discarded with the kitchen scraps.
How long rechargeable batteries can perform when fully charged is indicated by their mAh (milliamp hour) rating. The best NiMH AA cells are 2500 mAh or higher. Lithium ions are always lower, maxing out in the 1000 mAh range. Battery chargers range from slow (overnight) to ultra-fast (15 minutes). Chargers that pound energy into the cell too fast tend to break down the chemistry and shorten the overall battery life. Two-hour chargers offer a good compromise between charging speed and battery longevity.
Users of AA batteries have another option besides NiMH and alkaline. Super single-use cells, including Duracell PowerPix, Energizer e2 Titanium and Panasonic Oxyride, offer superior performance in a non-rechargeable format. If your camera uses a dedicated Li-Ion pack, you have fewer choices. In some cases, you can opt for a single-use substitute. These are handy to take along in case your rechargeable runs out of juice. Generally, though, you’re limited to selecting between a battery that has your camera maker’s name on it or a generic brand.
Generic batteries are often the same quality as branded. As with all shopping experiences, if you trust the store, you can probably trust the product. Just make sure that your search for a lower price doesn’t lead you to some phony brand that's being sold from someone's basement via an online auction. There are confirmed reports of actual counterfeit batteries being sold by rip-off artists. Some of these look-alike products have malfunctioned and damaged cameras and other electronic equipment. Buy from a merchant you trust and buy a name you know.
My friend Charley labeled his batteries and chargers, and I thought he was nuts—until one day when I couldn’t remember which Canon charger I needed for my PowerShot G5. Now I label chargers, AC adapters and everything else that could be hard to identify someday. I also label individual AA cells so I can use them in sets. It’s unwise to mix older and newer (or charged and discharged) batteries in the same device, so I mark each cell with a permanent marker on the day that I open the package.
Neither Li-Ion nor NiMH have memory limitations, so if you recharge them before they’re fully depleted, they don’t suffer any ill effects the way NiCd batteries do. Still, it’s a good practice to discharge batteries until they’re very low and then recharge them fully. NiMH battery chargers that offer a car adapter are handy—plug it in where the lighter goes and you can renew your batteries while you drive. Batteries lose a small percentage of their charge even when they’re not being used, so rotate your backup cells to keep them fresh. It’s not recommended to charge any battery for longer than 24 hours.
Never carry loose batteries in your pocket or gear bag. Keep them in their original container or a plastic bag to protect the electrical contacts. Don’t mix brands in the same device, and whatever you do, never mix rechargeables with disposables—that’s begging for trouble. And hopefully it goes without saying that you must never attempt to recharge single-use cells.
When you’ve been shooting longer than you’ve expected and see the power meter beginning to wane, there are a few common sense things you can do to prolong battery life. Turn off the camera's LCD and use the optical finder. The LCD display consumes more energy than any other part of the system. If you’re shooting with a D-SLR, disable the review feature. And, of course, if you minimize the amount of time you spend reviewing images, you’ll have more juice left to record them.