Battery Care

A comment made recently about the performance of Li-Ion rechargeable batteries has prompted me to publish a quick set of guidelines on how to get the best performance and life from your battery.

Most rechargeable batteries are now of the Li-Ion chemistry variety, which has, replaced the older Ni-Cad and NiMh technologies mainly through improved energy density by weight and volume. The most common applications include mobile phones, laptop computers, digital cameras and MP3 players.

One of the big claims about Li-Ion when it first started to appear on the market is that it did not suffer from the “memory effect” whereby if a battery is repeatedly only partially discharged before recharging, the battery "forgets" that it has the capacity to further discharge all the way down. For example, if you, on a regular basis, fully charge your battery and then use only 50% of its capacity before the next recharge, eventually the battery will become unaware of its extra 50% capacity which has remained unused. The battery will remain functional, but only at 50% of its original capacity. While, in theory, the Li-Ion chemistry should not display this condition the reality is slightly less than clear-cut. It is especially important in laptop batteries that you do not repeatedly “top-up” the charge. This will destroy your very expensive laptop battery in record time. I’ll not go into the reasons why but a large part of the problem is the “fuel gauging” that is built into a laptop battery. I’m sure you’ve all discovered that a laptop rapidly loses its ability to hold a charge after only a few months. Most laptops are used at the desk plugged into the mains anyway. If this is the case, remove the battery. Only recharge the battery when it is nearly fully discharged. To a lesser extent this will help the performance and life of single cell applications such as phones, cameras and MP3 players.

The top tips for rechargeable battery care are:

Temperature
Excessive high temperature will destroy a rechargeable battery’s capacity very quickly. New devices to keep laptops cool are now available for this very reason. Do not leave your mobile phone on the dashboard on a sunny day. The internal cell will be damaged, the battery will swell and could leak.
Break In New Batteries
New batteries come in a discharged condition and must be fully charged before use. It is recommended that you fully charge and discharge the new battery two to four times to allow it to reach its maximum rated capacity.
Prevent the Memory Effect
Keep the battery healthy by fully charging and then fully discharging it periodically.
Keep the Batteries Clean
It's a good idea to clean dirty battery contacts with a cotton swab and alcohol. This helps maintain a good connection between the battery and the device.
Exercise the Battery
Do not leave the battery dormant for long periods of time. It is recommend using the battery at least once every two to three weeks. If a battery has not been used for a long period of time, perform the new battery break in procedure described above.
Battery Storage
If you don't plan on using the battery for a month or more, it is recommend storing it in a clean, dry, cool place away from heat and metal objects. NiCad, NiMH and Li-Ion batteries will self-discharge during storage; remember to break them in before use.

Category:

• Battery
• Li-Ion