Most laptops (notebook computers) available use Lithium ion rechargeable batteries since they have a low weight and discharge slowly when not in use. A six month battery will discharge by about 10% if not used and not connected to an ac power supply for a period of one week. However, they last for a shorter time compared to other batteries and can be dangerous when overheated.
How to fix common battery problems:
1. Due to a problem in the charger circuit, the battery status may be shown as charged to 100% , but the laptop may not work when the electrical power supply is switched off. No power will be actually stored in the battery. You may either have to
a. Replace the charging circuitry
b. Replace the motherboard
Both these options are expensive for a laptop.
2. If there are batteries are physically present in the laptop, but the battery indicator does not show the status of the batteries. There could be problem with the connectors between the batteries and the laptop. Clean the connectors to remove oxidation. Fix the batteries back and ensure that there is proper contact .
3. When not in use, the batteries will discharge slowly. The rate of discharge increase for higher temperatures and older batteries. If they are discharged below a particular voltage, the batteries will be permanently damaged.
4. The average life of a battery is 18 to 24 months. If a battery has to be replaced, get a new one from manufacturer, a second hand battery may not last for long .
To increase the life of the laptop battery
1. Keep the temperature of the batteries as low as possible. Use it only for short periods of time, to prevent overheating.
2. Use the AC power supply for the laptop as far as possible, as this will reduce the usage of the battery.