Like all rechargeable batteries, a notebook computer battery's ability to hold a maximum charge will decrease over time or with use.
Lithium-ion batteries used in notebook computers typically have a lifespan of 300 to 500 charge cycles. After a year of use or 300 charge cycles, a Lithium-ion battery holds only about 80 percent of its original capacity. But there are ways to extend a notebook battery's life, which reduces the need to buy additional batteries, which in turn is good for the environment.
First, conserve battery power by reducing power consumption on your notebook. Hewlett-Packard recommends several steps, such as keeping the computer cool (between 65 and 77 degrees Fahrenheit). You can also try adjusting screen brightness, removing peripherals and lowering processor speed.
Second, because high temperatures accelerate the deterioration of Lithium-ion cells, keep the notebook away from prolonged exposure to heat (for example, don't leave it in your car on a warm day). Also, remove the battery if the notebook is turned off and not plugged in to an AC adapter for more than two weeks -- or if the notebook is plugged in to AC power continuously for more than two weeks.
Third, calibrate the battery. When users power up in fits and starts and then recharge without fully draining the battery, it reduces the amount of power available in a single charge cycle and can render the battery meter inaccurate.
There are four steps to calibrating a battery:
- Disable power management in the Microsoft Windows operating system and select "always on" in the power scheme. That prevents the notebook from going to sleep.
- Connect the AC adapter to the notebook and charge the battery until the meter says it's at 100 percent.
- Remove the AC adapter and drain the battery until the notebook shuts off.
- Reconnect the AC adapter, charge the battery and then turn Windows power management back on.
Last, Lenovo Master Inventor Howard Locker advises against leaving a notebook always plugged in. "The battery will last longer if it charges and discharges, so you don't want it 100 percent charged all the time," he explains. "Once in a while, let the battery drain." But contrary to popular opinion, he says, it does not have to drain completely the first time it's used.
- Should you set your computer to power off, hibernate or sleep? It depends.
- When initiating power settings, consider eliminating screen savers, which waste energy, says Lenovo Master Inventor Howard Locker.
- Desktops typically use 60 to 80 watts during normal use and 10 watts when idle. Notebooks use 10 to 30 watts under normal use, and 6 watts while idle. In hibernation mode, computers use zero watts, while computers in sleep mode use about 0.2 watts.
- There is a debate over which is most efficient. Going into and out of hibernation mode does consume considerable energy. And some argue that completely shutting down the computer hurts productivity because the boot-up time in the morning takes a few minutes.
- Locker's recommendation: Hibernate if you are gone for two or three days, but put it to sleep if you're only away overnight.