A Laptop batteryprovides a source of electrical energy that supplies needed power to your laptop. The laptop battery uses a combination of cells that are electrochemically active, which is to say, they naturally transmit electrons from one end of the laptop battery to the other, when those two ends are connected in a circuit. A laptop computer battery can be engineered to be highly portable, like a watch battery, or it can be built to withstand extremes in operating conditions, like a car battery.

Just like your car, your laptop batteries lasts longer or not depending on how you “drive” your laptop. Modern laptop batteries tend to last three to five hours, depending on the power needs of the computer and the programs the user runs. Few things are as frustrating as when your laptop battery suddenly won’t charge fully or stops holding its charge for as long; when this happens, you’ll probably want to buy a replacement battery.

Several years ago, when purchasing laptop battery, the first thing a consumer should look for is the type of battery. Batteries can be made using several chemicals. But now  there is no need for you to consider. Because at present, almost all the batteries are based on li-ion cells. There is no major manufacturer that still makes Ni-Cad laptop batteries, as they are a very old and primitive type of power. Ni-MH is newer and more advanced, but is not as good as its Li-Ion and Li-Poly counterparts.

So the first thing you should consider when buying a Dell latitude D620 Battery is the reputability of the product at mind. If the product is made by the manufacturer of your laptop, you can usually be sure it is a quality product. However, many manufactures do not actually manufacturer, instead they are the brander of the product. For example, if you open up a genuine HP batteries, you may find that the power cells inside are actually made by Toshiba, Panasonic, or a similar big name company. HP in this case has just made the plastic case of the battery. This goes to show that the brand of the battery you are buying does not necessarily mean that the quality is superior. Many third party brands use the exact same power cells as original manufacturers. Using a third party manufacturer is often a good way to go when buying a battery, as there are usually many extra benefits. For instance, most third party batteries are much lower in price than original manufacturers’ batteries. Secondly, they usually offer a superior warranty, as they realize that in order to win the consumer’s confidence; they must stand behind their product. A one year warranty is a must. Don’t buy any battery with a warranty less than one year. Batteries have been known to die early, and a three month warranty could leave you high and dry.

The next main thing a consumer should look for is how long do you intend to keep your dell notebook powered on while you’re away from an outlet? If the answer  is “not long,” or if you know there will be an outlet close by, buying an extended battery will not give you any tangible benefit.If, however, you know you are going to be nowhere near an AC power outlet and/or need juice in your notebook for several hours to an entire day, you will definitely be better off getting an extended battery or perhaps even two.

Lastly you must look at the power rating of the Dell batteries you’re buying. As technology advances, so do power ratings. The battery you bought last year may be twice as strong this year, and might even be the same physical size. Batteries have two main ratings on them: Volts and Amperes. Because laptop batteries do not carry a very large amount of power when compared to larger batteries such as car batteries, most companies show their ratings with Volts and Milliamperes. One thousand Milliamperes equals 1 Ampere. When buying a battery, always go for the battery with the most Milliamperes (or mAh). Batteries are also rated by Watt-Hours, perhaps the simplest rating of all. This is found by multiplying the Volts and the Amperes together. We will now show you an example of finding the Watt-Hours for our example battery.