Voltage

The volts of a battery refer to an electrical measure of energy potential. They indicate how much electric charge is available to the device from the battery. This number is usually printed directly on the original battery, allowing one to easily compare their original voltage rating with the voltage rating on the replacement battery. Replacement batteries should only be purchased when the voltage is reasonably close to that of the original battery. So, if the original battery is a 3.6 volt, a 3.7 volt replacement battery will work perfectly fine. However, a 7.2 volt battery may cause damage to the device in which it is used.

Amperage

"Amps" is an abbreviation of Ampere, a 19th century French scientist. This term refers to the capacity of the battery in terms of runtime. Many batteries use the term "amp hours", but this does not translate directly into actual hours because different devices put different amounts of strain on the battery. Many batteries also use the term "milliamps" of "mAh". This is simply a different way of saying amps, as 1 amp is equal to 1000 mAh. There is significantly more freedom available when choosing a replacement battery in terms of amps. Increasing the amperage in the replacement battery will only increase the amount of time the battery can power the device before it needs to be recharged. For all intents and purposes, the only limiting factor in choosing a replacement battery in terms of amps is size, as batteries higher in amps are often larger in physical size.

Watts

Watts are less frequently used in classifying batteries. This term can be though of as simply the voltage of a battery multiplied by the amperage of the battery. Although this term may be less helpful in determining the exact output of a replacement battery, the replacement battery chosen should be fairly close in wattage to the original battery.

Conclusion

Replacement batteries are often different from original batteries in terms of voltage and amperage due to the fact that they are often manufactured to be compatible with several different devices. While this may deter the average consumer from purchasing a replacement battery for fear of incompatibility, it is perfectly safe to use a replacement battery in any device as long as it meets or exceeds manufacturer standards. A difference in voltage is no reason to rule out a replacement battery, although the difference should be somewhat small. A difference in amperage will simply dictate the runtime of the battery, and can be altered according to the consumer's needs. The only real limiting factor in this area is the physical size changes of replacement batteries with different amperage ratings.

Bobby George is a technical writer for Low Cost Batteries