If you're going to purchase a cordless tool, then you should really think about getting one with Lithium ion batteries. They cost more, and it's easy to think you could just buy a cheaper model and get a spare battery, but it's not the same. Lithium ion batteries are a true hassle free solution.
 

I could easily have spent a fortune replacing the motherboard, the memory, the processor etc when it all came down to 2 dollar battery. What's more is these batteries are easy to get. What you need is a CR2032 available at most hardware stores like home depot and I've even seen them sold in Safeways. Of course every reputable computer lithium ion battery stocks store should stock them. Just check to make sure that your PC uses a CR2032 before you go to the shops!

There are several types of battery in use at the present time and each must be treated differently. There are Nickel-Cadmium (Ni-Cad), Nickel-Metal Hydride (NiMH) and Lithium-ion. Ni-Cad is old technology and hence only found in ancient handsets, so I will not be covering them in this article. NiMH batteries perform much better than Ni-Cad, typically giving 30% more talk time, but Lithium are thinner and give even higher performance. I will be concentrating on lithium facts-ion as it is the most used modern mobile phone battery to date. Check which type of battery your phone has before following any of the following.

Laptop computers, without a doubt, are the lifeblood of many a businessperson today. Portable, convenient, they allow us to work on the run and do more business. Laptop batteries are essential to keep this resource working, as it should.

Avoid using replacement that has been on lithium bettery stock for a while. During storage the battery can lose much of its capacity through internal resistance, which damages it and lowers the maximum capacity.

As mentioned earlier, there are different types of batteries. You can choose a lithium ion battery if your primary source is electric power supply, but you do switch from fixed power to a battery on a regular basis. A Nickel based battery is preferable if you use a battery as your primary source.

The bottom line, be gentle to your lithium-ion batteries. If you excessively charge the battery, with high voltages, and heavy load conditions, it will shorten your battery's life. It's best to charge at a slower rate.