Lithium-Ion batteries have a finite life, they slowly degrade from the day they are first made. The life of the battery will depend upon how you charge and discharge the battery and the temperature at which the battery is kept. A manufacturer will rate a Notebook battery to the point where it holds 50% of its original capacity. At this point you should consider replacing the battery.

Li-ion batteries are not as durable as nickel metal hybride or nickel-cadmium designs and can be extremely dangerous if mistreated. They are usually more expensive.

Lithium ion batteries can be formed into a wide variety of shapes and sizes, so as to efficiently fill available space in the devices they power, but li-ion batteries are lighter than other equivalent secondary batteries.

The energy is stored in these batteries through the movement of lithium ions. Lithium is the third lightest element, giving a substantial saving in weight compared to batteries using much heavier metals. However, the bulk of the electrodes are effectively "housing" for the ions and add weight, and in addition "dead weight" from the electrolyte, current collectors, casing, electronics and conductivity additives reduce the charge per unit mass to little more than that of other rechargeable batteries. The forte of the Li-ion chemistry is the high open circuit voltage in comparison to aqueous batteries (such as lead acid, nickel metal hybride and nickel cadmium).

One important thing li-ion batteries do not suffer from the memory effect. They also have a low self-discharge rate of approximately 5% per month, compared with over 30% per month in nickel metal hydride batteries and 10% per month in nickel cadmium batteries.

Here is a quick list of Do's and Don'ts for the care of your Li-On batteries :

Do's

When you receive a new NoteBook or Tablet PC, leave the battery to fully charge overnight.

Condition a new battery by using it until it is fully discharged, and then re-charge it fully. Doing this once a month will help to accurately calibrate your battery.

Always ensure the battery is recharged as soon as possible after it becomes fully discharged. A battery will be permanently damaged if left for an extended length of time in a fully discharged state.

Remember that a Lithium-Ion battery will slowly deteriorate; a new battery will always perform better than one that is 6-months old.

Remember that the battery half-life is rated for a certain total number of charge/discharge cycles (see your User Manual or Quick Start Guide for the rating). For example, a battery that is rated for 3 hours and 500 charge/discharge cycles, will still be considered as within specification, even if it only lasts for 1 hour 45 minutes after 500 charge/discharge cycles.

Heat is the worst enemy of a battery. Allow plenty of air to circulate around the Notebook/Tablet PC, so that the battery is kept as cool as possible when charging and also when in use. If provided, use the integrated 'legs' under the Notebook to raise the notebook and improve air circulation.

Remove the battery if storing for several months (the battery should be at approximately 50% charge or higher).

If you use a NoteBus or if charging your Notebooks or Tablet PCs in a confined space, allow for adequate ventilation in order to keep the batteries as cool as possible.

Don'ts

Do Not - Expose the battery to excessive heat or cold (i.e. outside the range of 10-35 degrees Centigrade ambient).

Do Not - Store the battery in a fully charged state (store batteries with about 50% charge).

Do Not - Allow a nearly flat battery to be unused for more than a month or so. The battery will slowly discharge until it becomes fully discharged and this will permanently damage the battery cells.

Do Not - Charge your Notebook/Tablet PC inside a carry case - the battery may overheat.

Do Not - Charge your Notebook/Tablet PC when stacked on top of each other - the battery may overheat.

Remember : Your battery is slowly degrading all the time, even if it is not used. Keeping your battery as cool as possible will slow down this degradation considerably.