I regularly get asked for advice on buying a new battery or replacing a battery in mobile devices especially in laptops, so here’s a little article that I feel should help you to understand the technology and decide what to do.
The Technology in Batteries
Modern mobile devices use a type of battery derived from the Lithium Polymer (Li-Po) technology, Lithium Ion (Li-Ion) to be precise. Lithium Ion is very similar to Lithium Polymer in the fact that it has large energy storage capacities and smaller size and weight when compared with other types of rechargeable batteries such as Lead Acid (Pb), Nickel Metal Hydride (Ni-MH), and the older discontinued Nickel Cadmium (Ni-Cad) batteries.
Benefits of Lithium Based Batteries
Lithium batteries have many benefits over legacy technologies in terms of performance, they contain huge amounts of power for their size, weigh much less than any other type of battery and take up less room when compared with other technologies of equivalent capacity so they are perfect for mobile devices of all shapes and sizes. They tend to cope with demanding requirements and heavy power drains a lot better than other types too.
As with any technology there is always a certain caveat that works against it and with Lithium Polymer & Ion based batteries these present themselves in one or two troublesome characteristics. They are expensive, they have a maximum and minimum voltage range that must not be exceeded otherwise irreparable damage will occur causing the battery to store less energy and they have a much lower maximum charge count than all other current technologies. One big problem with Lithium Polymer (Li-Po) batteries is that the liquid core is unstable and can cause the battery to burst into a self-fuelled fire if a cell is miss treated (e.i. overcharged, short circuited or even pierced) and therefore taking away the oxygen supply will not put it out at all. This has been a huge problem for the Radio Controlled Models and Aircraft industries to the point where some airliners refuse to carry Li-Po batteries at all.
Why Lithium batteries cost so much
The main reason for the high price of Lithium Ion batteries is that there aren’t many places you can get Lithium from, extracting Lithium causes environmental damage and large amounts of research and development has gone into the technology which also requires covering in the cost.
Replacing a battery
It is inevitable that at some point you need to replace your batteries. Manufacturers only guarantee them for around 6 months and they are classed as consumables so don’t expect to get a new battery under the product warranty, unless you can provide proof of the battery failing within the required terms that warrant a replacement.
The best places to start looking for a replacement battery are on ebay and Amazon. Although you could always go to your manufacturer to get a guaranteed identical replacement that will perform within the manufacturers specifications, there are hundreds possibly thousands of sellers on ebay selling replacement Li-Po / Li-Ion batteries for all manufacturers of laptops and mobile devices, but be careful who you choose to buy your battery from.
Choosing a battery
If you are buying from ebay, then there are a number of factors to consider. The price, the feedback, the individual product feedback and where it is coming from.
Starting with price; does it sound too good to be true? The answer is usually if it does, then it is. Steer clear of any seller that is offering an unimaginably cheap replacement battery for your laptop. You will find that this is usually one of those cases where it is too good to be true. On average a good laptop battery should cost around £50 including postage at today’s (December 2012) prices.
Secondly, the seller’s overall feedback; Do they have a reasonable feedback rating in percentage? If a seller has a 97% rating, look at the total items that they’ve sold. If it’s below 100 items then you should probably think twice about buying a battery from them, if you’re still considering it then look at the individual feedback from each customer and see what it says about the item you’re thinking of buying. Are there any negatives? Are these negative feedbacks recently or within the last year? A seller who has sold 10,000 items with a feedback of 97% has managed to satisfy 9,700 of their customers and I would deem that as acceptable, but would not consider a seller who has a lower percentage with such high volume of sales.
Thirdly, look for the item you are looking at purchasing in their feedback. What are others who bought this item saying about the item. If there are any negatives then check for other feedback on the same item. If there aren’t any more negatives then you should be sufficiently satisfied that this is a good buy.
Lastly, where is the battery coming from? Most of today’s batteries are manufactured somewhere in Asia, so there are always lots of people selling from China. The only problem with buying something from China is that you can sometimes get stung by Inland Revenue for import taxes which in turn inflates the price of the whole transaction so try to buy from the country you reside in.
Looking after your battery
Believe it or not, Lithium based batteries don’t really like to be used. They have a maximum charge cycle count which means that they will only work for a certain amount of charges and discharges. This figure can vary but it is usually around 1000 times. If you regularly charge and use your laptop/mobile device without the mains adaptor plugged in and thrash the battery you are using up it’s lifespan.
Think of a battery as a regular rubber balloon. When you charge the battery, you are inflating the balloon and obviously when discharging the battery through normal use you are deflating the balloon. Over time the balloon will lose it’s elasticity and won’t require much effort to inflate, also won’t push the air back out with as much force as it did when inflated the first time round. This analogy is exactly like how a Lithium Based battery behaves. The more you use it, the less powerful it’s output becomes over time.
If you want to make your battery last longer, try to keep your device plugged into the mains whenever possible, don’t let the battery fall below half charge and certainly don’t thrash your device until it switches itself off because of a depleted battery – Exactly the opposite of those care instructions for devices with Nickel Metal Hydride (Ni-Mh) batteries.
Remove your battery
Take your battery out if you’re not using your device. Believe it or not when a device is switched off, it is still using energy, albeit at a very small rate but enough to slowly discharge the battery when not being used for long periods of time and if left for long enough, as with totally discharging a Li-Po / Li-Ion battery damage WILL occur to the individual cells resulting in reduced capacity and shortened run-time in the device.
Remember that by removing the battery from things such as cameras and phones, the clock may need to be reset the next time you go to use the device if the battery has been removed for a long enough period of time.
Laptops do work without the battery installed. You can take the battery out and plug it in while the laptop is switched on. It won’t harm the device but it will prolong the life of your battery by leaving the battery out. If you need to unplug your device from the mains to move it elsewhere, then plug the battery in and wait a few seconds for the device to recognise the battery and then disconnect it from the mains.
Hopefully this will help you to understand batteries and how to look after them a little as well as give you information I feel is important when considering buying a new battery.