The question of extending laptop battery life is one of the most vexing concerns of many of those who take advantage of mobile computing. A laptop battery can be a very expensive component to replace, with most costing at least $100 US Dollars (USD) and some costing considerably more than that. Therefore, it is to the computer owner's advantage to follow a few simple steps to extend battery life.
Of primary importance is to know the type of battery you have. For example, lithium ion batteries work differently than NiCD or NiMH batteries. The latter two should be fully discharged to avoid a memory effect, which will work to deplete the battery life of a laptop. The lithium ion battery should never be fully discharged.
Whenever possible, avoid needless recharge cycles. Any rechargeable battery has only so many of these. Discharging a battery for a few minutes, then plugging it in could prematurely cause laptop battery life to decrease dramatically. Rather, if you do not need the battery and it is charged or even if it is not charged, take it out and run off the cord.
Most laptop computers have power saving settings. Use them. Nearly every computer expert will tell you this, for a good reason. It simply may be the best way to extend laptop battery life. Dimming the screen, hibernation, not running the CD/DVD drive any more than absolutely necessary when on the battery all will help.
Use the battery at least once every couple of weeks. While this may seem counterintuitive given the instruction to avoid needless recharge cycles, it is not. This is because in order to get the most battery life possible, you must use it. Rechargeable batteries need to be worked or they will lose their effectiveness. This does not mean recharging the battery after every 15-minute use, but rather using the battery for substantially longer periods of time.
For those who rely heavily on their battery, consider a long-life laptop battery. This will help extend times needed between charges, cutting down on the number of recharging cycles needed. While this may seem like an expensive option, it also provides the added benefit, if you already have a standard battery, of having a backup when away from a corded power source.
Watch the use of peripherals, which can substantially drain energy from the battery. If running on battery, use the touchpad instead of the USB mouse. Avoid other such connections as well, as these tend to drain laptop battery life.
Defragment your hard drive regularly. This is a good idea even for desktops, but it is especially important for laptops. Defragmenting should be done when on corded power as it takes a substantial amount of resources to do. However, a properly defragmented hard drive will help keep your hard drive from working harder than it has to when it is on battery power.
Also, don't run unnecessary programs or devices. This will also cause your battery to drain prematurely. When extending the laptop battery life is a concern, this may be one of the easiest things to do. For example, if there is no WiFi access where you are, having that component turned on is nothing but a waste of resources.