Q: My computer is two years old and I have always used the electric mains to run it. So, I have never used the battery.

Recently, the battery indicator started blinking red or blue. I then used my computer running on the battery when it was fully charged. But the blinking has not stopped.

What is the lifespan of a battery if it is not used?

Piyush Jain

A: Over time, the internal components that make up a battery will break down and not work even when the battery has never be used.

It would probably have been better for you to use the computer running on the battery.

Depending on the battery type, that is, Lithium-Ion (Li-Ion) or Nickel Metal Hydride (NMH), the battery's shelf life will be different.

You need to be especially careful with Li-Ion batteries because they have a safety mechanism that turns the battery off when the voltage falls below a minimum, like 2.5V per cell.

When this happens, there is no way to restore or charge the battery. The circuit will always show the battery is dead.

A rechargeable battery like the Li-Ion of a notebook will, over time, lose the ability to hold the original maximum charge.

You will lose about 20 to 25per cent of the charge capacity each year. However, other factors will also affect life of the juice pack.

The big killer of most batteries is heat and load. An example of a bad storage condition is to keep the notebook with its battery in a car on a hot sunny day.

Temperatures in the car may reach over 45 deg C and that will degrade the battery.

Time is not on your side either for battery operation as well as recharge and discharge cycles. It is similar to the vehicle warranties which states that parts are guaranteed for three years or 60,000km, whichever comes first.

Similarly, most batteries are guaranteed against failure for one year. Notebook manufacturers will also state the maximum number of cycles - usually 500 charges - for the device.

In terms of day-to-day usage not including weekends, you are likely to get about two years' worth of charging.

Answer by Chester Chen, a recognised Microsoft Most Valuable Professional specialising in windows desktop experience

This story was first published in The Straits Times Digital Life.

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