Rechargeable batteries, unlike traditional batteries, can be connected to a charger to bring them back to life. They are less wasteful thanks to their ability to be recharged between 500 and 1,000 times, and although they initially cost more than traditional batteries, they require replacement less frequently.
The letters "mAh" stand for milliampere hours. Milliampere measures a unit of electric charge, and tells a user how many electrical currents are released in an hour.
The higher the number preceding the letters "mAh," the longer the battery will last. For example, if the label on the battery reads "2500mAh," it means the battery is getting 2500 milliampere an hour. Typical rechargeable batteries are rated between 1800mAh and 2700mAh, and can be purchased in different sizes such as AA, AAA and 9V.
Digital cameras, digital video recorders, PDAs and hand-held video game systems are considered high-drain devices, and typically use batteries with a higher mAh, like 2500mAh. These devices perform better with rechargeable batteries that have a higher mAh, and the device last two to four times longer than with traditional batteries as well.