Laptop batteries

A common misconception is that you must regularly run your laptop batteries flat or you will sacrifice battery life

This is the conventional wisdom among a lot of notebook users and stems from the days when most laptop batteries were of the NiMH or NiCd type. Nickel-Metal Hydride (NiMH) and Nickel Cadmium (NiCd) batteries suffer from the `memory’ effect which means that their performance is reduced unless the battery is fully discharged and charged on a regular basis. If these batteries are only partially discharged before being recharged they forget their true capacity and battery life is increasingly shortened.

There are almost no laptops with NiMH or NiCd batteries around these days. All the new laptops come with Lithium-ion (Li-ion) batteries. Li-ion batteries do not suffer from the memory effect and therefore do not require regular full discharges and recharges. However, a new Li-ion battery should be conditioned the first time you use it by being fully charged and discharged three or four times. Do not overcharge a Li-ion battery by leaving it on a charger for more than 24 hours.

Try not to leave your battery unused for long periods of time. Turn on your notebook every now and then (say fortnightly) to exercise the battery. If a battery has been left dormant for a long period of time, perform the new battery conditioning ritual before reuse.

By Alan Chew

Managing Director of the Houston Technology Group

This article appeared in the April 2009 edition of the Waikato Business News, for which Alan writes a regular column as "Your IT Adviser".