How Long Do Rechargeble Batteries Last?

Nickel Metal Hydride

• Nickel metal hydride rechargeable batteries rely on nickel alloy and nickel oxide electrodes immersed in a solution of potassium hydroxide to create the battery cell. Nickel metal hydride batteries typically last between 300 and 400 recharge cycles, which equates to a lifespan of between 12 and 18 months. They typically last up to 40 percent longer than nickel cadmium batteries of the same size, making them useful for high-energy devices, such as laptop computers and cellular phones.

Lithium Ion

• Lithium ion rechargeable batteries employ graphite and lithium oxide electrodes immersed in a solution of a lithium salt dissolved in a mixture of organic carbonates. Lithium batteries have become the batteries of choice for portable devices in recent years because of their high energy density and high voltage compared with nickel-based battery technologies. Lithium ion batteries typically last between 300 and 500 recharge cycles or between 2 and 3 years, whichever happens first. However, if they are charged, discharged or stored incorrectly, their life expectancy may be shortened.

Self Discharge

• Almost all rechargeable batteries slowly lose their charge over time, even if they are not in use or connected to a device. The rate at which batteries lose charge in this way is known as their self-discharge rate. Nickel metal hydride batteries have a high self-discharge rate, typically between 2 and 3 percent per day, while lithium ion batteries have a self-discharge rate of around 5 percent per month. Note that if rechargeable batteries cannot hold a charge for long periods, even when charged correctly, they may be coming to the end of their lifespan.

Battery Care

• Rechargeable batteries irreversibly deteriorate over time, but their life expectancy can be extended by charging, using and storing them correctly. Batteries can be damaged if too much charge is applied during the charging process, so lower charge rates extend their overall life. Similarly, small differences in current, voltage and capacity can reduce the life expectancy of rechargeable batteries, so avoid mixing different brands in the same device. Store rechargeable batteries in a cool, dark place, preferably in their original packaging, and check on their charge status at least once every six months.