How to find the right battery for the job
Batteries supply the energy for many items in your home, from your kids' toys to your remote controls. There are three main types of batteries on the market today. The cheapest, and the most widely available, is the old-fashioned alkaline battery. Made by familiar brands like Duracell, Energizer and Eveready, these typically cost around $2 for a pack of two AA batteries, the most common size. However, alkaline batteries don't last as long as other types, especially when used in power-hungry devices like digital cameras.
Lithium batteries, like alkaline batteries, are disposable. However, they also last much longer, so you won't have to dispose of nearly as many. In one expert test, a typical lithium battery lasted about 50 percent longer than a typical alkaline battery at a low power drain of 200 milliamps (mA), which is about the amount used by a child's toy or a flashlight. At a higher power drain of 1,000 mA, comparable to a digital camera, the difference was even more dramatic: The lithium batteries lasted nearly three times as long as the average alkaline.
The downside to lithium batteries is they cost a lot more than alkalines: around $8 for a pack of four AA's. This means that for low-drain devices, the old-fashioned alkaline actually gives you a lot more bang for your buck. A lithium battery will last about 50 percent longer, but it'll cost twice as much. However, for high-drain devices, lithium batteries provide a better value, as well as saving you the trouble of toting around extra batteries wherever you go. Lithium batteries are also lighter in weight than alkalines, and they function better at extremely low temperatures -- both useful qualities for winter camping and hiking.
Rechargeable batteries are the most expensive type, costing anywhere from $8 to $17 for a pack of four AA's. However, for most uses, rechargeable batteries are the best long-term value. That's because batteries of this type can be recharged and used again and again -- anywhere from 300 to 800 times, according to energy experts. If you pay $20 for a set of four AA batteries and a charger, and you use the batteries 500 times before they wear out, their cost per use (including the electricity used for charging) comes to around 5 cents. By contrast, 500 4-packs of alkaline batteries would cost around $2,000.
In addition to being more cost-effective, rechargeable batteries are a greener choice. Choosing one rechargeable battery instead of 500 alkalines reduces the amount of waste by a factor of 500. It's also easy to recycle rechargeable batteries at the end of their life by dropping them off at locations such as Lowe's, Home Depot and Radio Shack. Disposable batteries, by contrast, can't be recycled in most areas.
However, rechargeable batteries have a few drawbacks compared to disposables. One problem is they tend to lose their charge over time, so batteries kept in storage may need to be recharged before use. This makes them less suitable for emergencies. However, choosing low self-discharge (LSD) rechargeable batteries, such as the Sanyo Eneloop, can reduce this problem significantly. Another problem with rechargeables is that it's hard to find them in sizes other than AA and AAA. We found only one well-regarded brand, the Powerex Imedion, that comes in all standard sizes, but it's not widely available in stores.
To find the best batteries, we considered two main factors: performance and longevity. Performance includes battery capacity, how long batteries last in storage and, for rechargeable batteries, how long it takes to charge them. Longevity, for alkaline and lithium batteries, is simply a question of how much power they can deliver before running down. For rechargeable batteries, longevity also includes the number of times they can be recharged. Information about both performance and longevity can be found in professional battery tests conducted by consumer magazines and online publications. User reviews from Amazon.com helped us find information about specific problems with batteries, such as which brands are most likely to leak.