Battery boost

Most of today's portable gadgets are powered by Lithium-ion batteries and although these are durable and efficient, there are ways to squeeze even more juice out of them. Curious? Read on as WinLabs Editor Jason Saundalkar explains...

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By  Jason Saundalkar Published  April 14, 2008

As an electronics nut one of the most frequent questions thrown at me is ‘how do I make my battery last longer in my notebook or my digital camera? Well, depending on the battery the product is using, there are a number of things you can do outside of using the product's own power saving features.

Today, Lithium-ion (or Li-ion) batteries are one of the most common battery types in the mobile consumer electronics segment. These have been adapted to power everything from mobile phones to notebooks and more.

Li-ion batteries are widely used in this segment owing to a number of beneficial properties, including high energy-to-weight ratios, no ‘memory effect' and lastly, a slow loss of charge when not being used. An energy-to-weight ratio is essentially a ratio of how much energy can be stored in a given region of space per unit volume (in this case the battery). A high ratio means that although the battery doesn't actually weigh a lot or take up much space, it can still hold a high amount of electric charge. As a result, the Li-ion batteries designed to power portable devices don't have to be big and bulky to provide long usage times.

Memory effect (known also as lazy battery effect) is an affliction some rechargeable batteries - such as Nickel-Cadmium (NiCd) - suffer from. It causes these battery types to lose their maximum storage capacity after every charge and discharge cycle. That said Li-ion batteries will eventually lose their storage capacity though this is because of age rather than constant charging and discharging of the battery, as is the case with NiCd.

On the flip side, like every other battery type, Li-ion has its drawbacks that ultimately sap away performance. The major niggle is that this battery type is susceptible to heat. Most manufacturers I've talked to say that a Li-ion battery will lose roughly 20% of its storage capacity each year, if it is always at maximum charge and operating at a temperature of 25-degrees Celsius. The loss increases to 35% should its temperature be 40-degrees and if its temperature increase beyond this, the storage loss will increase further or worse still, the battery could explode. The latter may not be a problem in the future however, as scientists have just discovered a way to produce Li-ion batteries without flammable materials, read the story here. On the other hand, Li-ion batteries can also be damaged if the temperature drops to -40-degrees Celsius. So, my first tip to making sure your Lithium-Ion battery lasts longer is to make sure it isn't running too hot.

The second related tip is to make sure your battery isn't always fully-charged. Vendors say that if a charge level of between 40% and 60% is maintained, a Li-ion battery will typically lose 2%, 4% and 15% of its storage capacity per year when running at temperatures of zero-, 25- and 45-degrees Celsius respectively. These percentage figures are much less than if the battery had a full charge at the mentioned temperatures.

In the case of laptops then, if you find you're always working from a wall socket, you should remove the battery pack entirely as this way, it wouldn't always be charging to its full capacity. You should also try and avoid placing the laptop on any surface that will restrict air flow around the battery as this will increase its running temperature. (Working with your laptop sitting on your bed or even on your lap for extended periods of time will definitely reduce the battery's storage capacity over time.)

Another way to keep your Li-ion battery's performance strong is to make sure it isn't completely flat for long periods of time. Doing so, the battery may go into a state known as ‘deep discharge'. Should this happen, the next time you charge the battery you'll notice that it's taking longer than normal for the battery to fully charge. For example, rather than taking the standard two hours to charge, it may take five hours or more depending on how long it was left discharged. In the worst case, if the battery is left unused for very long (over two years), the battery may never come back to life.

So, if you're not using a portable device as much or if you've bought a spare battery for your MP3 player, camera or notebook for example, the best way to look after the battery is to make sure it has a charge of between 40% and 60%. Also, ensure that it is kept in a temperature controlled environment that maintains a temperature of between zero and 25-degrees Celsius. (I usually store my spare laptop battery in my fridge at a temperature close to zero degrees Celsius. I know this sounds weird but trust me on this, it's good for the battery.)

If you follow these tips, your Li-ion battery will not only have a longer life span but it will also ‘age' at a slower pace in the storage capacity department. You can also apply these tips to anything powered by a Li-ion battery, just have a look at the battery of the device in question, as most are labelled to say what battery type they are.

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