If you are among the increasing number of mobile executives who are switching from PCs to laptops, it is inevitable that you will soon face a situation where you will need to educate yourself about laptop batteries. And then, at some point, buy them. Here are some basic guidelines:
Brief Background of Laptop Batteries: The earliest type of battery used the chemicals Nickel Cadmium (NiCd, NiCad), and was very quick to charge and was also able to handle high loads. However, these chemicals are highly toxic. The next generation of batteries, the Nickel Metal Hydride (NiMh, NiMH) batteries, now use Nickel and other rare earth metals as its electrodes and Potassium Hydroxide as the electrolyte. These are more environmentally friendly than Nickel Metal Hydride, but suffer from the memory effect, and have a short lifespan. A newer type of battery is the Lithium Ion (LiIon, Li-Ion) powered battery. In spite of being smaller and lighter than NiCd and NiMH batteries, it provides the same capacity. Also, these batteries do not suffer from "memory effect" and have low levels of self-discharging.
The Lithium Polymer Ion Battery: This is the latest type of battery chemistry. Though this behaves in the same way as Lithium Ion, there are some important differences. The Lithium Polymer Ion Battery uses a thin plastic-like film as the electrolyte, resulting in considerably reduced weight, and a greater power to weight ratio than most of the other types. They are used in Universal Laptop Batteries. So this is the type to look for, when you need a new battery for your laptop.
What are Universal Laptop Batteries?: Most of the top manufacturers like Sony, Compaq, fujitsu, Toshiba, Panasonic, Dell, IBM, Lenovo Apple, HP, are providing the Lithium Ion battery technology. The Universal Laptop Batteries, however, use the more advanced Lithium Polymer Ion chemical. A universal battery is just a larger version of the standard laptop battery, and can power virtually any laptop.
The universal batteries are rechargeable - the AC Adapter and power lead are provided by the manufacturer. Also, the manufacturer supplies a number of tips that fit the power supply connector on the laptop. These tips enable the smart electronics embedded in the battery to supply electricity at the correct voltage.
Another plus point in favor of universal laptop batteries is that the continuous usage time is up to 10 hours at a stretch. (Of course, there are variations according to manufacturer and model of the universal laptop battery.)
When do I need a new battery?: You do not necessarily need a new battery only after the current one is completely used up. Some laptop manufacturers offer laptops with expansion slots that will accept a variety of peripherals, including a second battery. This second battery can double your battery life. But, if you are planning to get a lot of work done on that long flight, then it may be time for you to purchase a new laptop battery.
Remember: When buying batteries, ensure that the supplier and the manufacturer are reputable. Be sure that the Supplier/Manufacturer offer full guarantee and warranty. Check the chemistry and dimensions of the universal laptop battery before purchase. And provide the supplier with all the information about your laptop such as the make, the model, the part number, the Voltage and Current ratings (provided in the manual or underside of the laptop) in order that the supplier can assist you with the most suitable battery.
Samantha Spiegla recommends that you visit
http://www.computerbatteries.co.uk for more information on
laptop batteries and notebook power adapters.
Laptop Batteries 101 - A Buyer's Guide 
