Most battery-powered hand tools use at least one of three battery packs: 18V (Volt) for standard power tools, 12V for compact and lower-power-demand tools, and 36V or higher for some outdoor gardening and landscaping tools. All battery packs are made up of individual battery cells. Each cell has a specific nominal voltage, typically 3.6V, which is the amount of power it produces. Three cells are wired together in series to make up a 12V battery pack, and five cells for an 18V pack.
Batteries have an amp-hour (Ah) capacity, depending on the density of the battery cells. The Ah is a measure of battery capacity, commonly referred to as the “run-time”—essentially how long the battery will produce power. It’s comparable to the size of the gas tank in a car: the larger the tank, the more gas it carries, and the farther the car can travel. Runtime will depend on the environment and the application in which the power tool is used. The more energy a battery can store, the longer the battery can run before it needs to be recharged—and the more work you can get done.
Another measure of battery capacity is the watt-hour (Wh), which represents the amount of energy (in watts) the battery can supply per hour. It’s comparable to the gas in a car’s gas tank. Watt-hours are determined by multiplying the battery voltage (V) by the amp-hour (Ah) rating. For example, an 18V battery with an 8.0 Ah rating supplies 144 nominal watt-hours of power, while an 18V battery with a 6.0 Ah rating would supply 108 watt-hours.
For more information read Next Generation Batteries: what manufacturers are doing to enhance user productivity
