Is Battery Life the Same?
Battery life is not all the same. Batteries will last various lengths depending on many factors, with one in particular being drain currents of a device. Devices that require large amounts of power, such as digital cameras will use more power from a battery, decreasing its useful life. Devices like smoke detectors and watches do not require as much power, therefore the battery powering the device lasts longer.
To determine battery life, simply divide the capacity by the actual load current to determine the hours of life. A circuit that draws 10 ma powered by a 9 volt battery will function for roughly 50 hours. (500 mah/ 10 ma) The cell voltage of alkaline cells decreases with usage from 1.5 volts to around 1.25 volts when half discharged. The voltage is around 1 volt when the battery is discharged.
It is also noteworthy that alkaline batteries exhibit a slightly increased capacity when warmed and the capacity significantly drops at temperatures below freezing. Lithium batteries perform better at extreme temperatures and should be used when applicable.
It is best to keep this in mind when choosing a battery for a particular device. If you have any questions on which battery to use, do not hesitate to call the experts at Medic Batteries at 800-479-6334.