"Different batteries have different performance levels best suited to different electronic devices," says Chao-Yang Wang, Ph.D., associate professor of mechanical engineering and director of the Electrochemical Engine Center at Pennsylvania State University. "It's like a marathon runner versus a hundred-meter sprinter. One needs endurance; the other needs bursts of power." From remote controls to digital cameras, all battery-powered electronics fall into one of three categories.

HIGH-DRAIN

Types of devices

Digital and flash cameras

Personal organizers

Remote-control toys

Hand-held TVs, two-way radios, and other electronic devices that require large bursts of power

Best performance: The newest premium alkaline batteries work best in high-drain devices, but at a cost. A single Duracell Ultra AA battery, for example, lasts about twice as long in a high-drain device as a standard alkaline but costs more than double. Lithium AA cells are another option if you want the convenience of not having to change batteries too often and aren't concerned about cost.
Best deal: If you use the device almost every day, the most economical option is NiMH batteries, which can be recharged up to 1,000 times and deliver as much power as premium alkalines.

MODERATE-DRAIN

Types of devices

Portable stereos and CD players

Game Boys

High-use flashlights

Most electronic toys

Best performance: Standard alkalines, such as Duracell Coppertops, are best for frequently used electronic devices.
Best deal: Rechargeable NiMHs are also a good choice in this category, though they require an initial cash outlay of $30 to $50 for a charger with four AA batteries. But that cost is recouped after 20 rechargings.

LOW-DRAIN

Types of devices

Pagers

Wall clocks

Remote controls

Smoke detectors

Emergency flashlights and other low-power or infrequently used devices

Best performance: Once again, standard alkalines are the way to go. Resist the urge to buy cheapee carbon-zinc general-purpose batteries. Their short life spans make them cost more than alkalines in the long run. NiMHs, because they slowly discharge over time, are not suited for long-term placement in low-drain devices.
Best deal: Alkalines, for the above reasons. TIP: When your AA batteries are too spent to run your Walkman (a moderate-drain device), they can still have enough juice to power a low-drain wall clock or remote control.