It is difficult to predict how long a laptop battery charge will last because each computer user has different habits and needs. The rate at which you use laptop battery power will determine how long you can use the battery of your laptop. You can re-calibrate your laptop battery if the battery's life has gotten shorter over time. Your laptop battery might need a good calibration if it does not seem to be getting the mileage that it should. How to re-calibrate laptop battery? The following paragraphs will give you the answer.
First put the laptop computer to sleep by turning off the screensaver and other power management settings of the computer. Then fully charge the computer and allow it to run all the way down until the computer shuts off automatically. Once the laptop battery has fully drained, charge it back up again and restore the screensaver and power management settings.
Re-calibrate your battery every month or so by fully charging, fully discharging, and then fully charging again. Basically to have a chance to re-calibrate your laptop battery is to turn off all power-saving features completely and then fully recharge them. If it does not work for the first time then try two more discharges and recharges.
The above way of re-calibrating the laptop batteries works well with laptops using Ni-MH cells. But not with laptops using Li-Ion batteries because deep discharges will actually decrease the charge capacity and lifespan of Li-Ion cells. Moreover Li-ion batteries irreversibly lose approximately 20% capacity per year from the time of manufacture at a typical 100% charge level at 25deg.C, even when unused. Li-ion batteries irreversibly lose approximately 2%, 4%, 15% at 0deg.C, 25deg.C and 40deg.C respectively, when stored at 40% charge level. That is every deep discharge cycle decrees the capacity of the Li-ion batteries. As the Li-Ion batteries are chemical in nature, charging and recharging is not going to fix the problem once the chemical reactions stop happening. Therefore the best advice for re-calibrating the Li-Ion batteries is to store the battery at 40% charge if it kept unused for any unlimited period of time. Also do not leave the battery in the laptop if you do not use the battery or if you plug the laptop into outlet power.
You can also re-calibrate your laptop battery using IBM Thinkpad Battery Maximizer in order to maximize your laptop battery's life. If your laptop has IBM ThinkPad Battery MaxiMiser and Power Management features installed, you can verify the condition of the laptop battery. You can check the status of your battery using the Battery MaxiMiser Gauge in the taskbar tray. The ThinkPad's Lithium Ion battery pack that seems to be an intelligent battery uses a microprocessor to monitor its capacity. Then the microprocessor of the battery pack passes the information about the remaining battery capacity to the laptop. The laptop indicates the capacity with high accuracy.
Using the HP Laptop Battery Learning Utility, a modified version of a Win98 boot floppy, can also help you. Just place it in the floppy drive, and then turn on the computer. The re-calibration process is automated and takes about six hours to finish. This utility is available in different versions for different models. You can run the utility every two months.
If the laptop battery is still bad then it must have developed a memory that can not be erased easily. If calibration does not help, then it is the right time to purchase another battery.