Nickel Cadmium batteries came with the first cordless power tools but were surpassed by the efficiency of Nickel Metal Hydride batteries. Lately, the battery technology in most new tools has been Lithium Ion. Lithium Ion batteries pack more capacities and can, therefore, last longer between recharges. This makes them perfect for those who work for some considerable time with their tools because increasing time taken before needing to pop out the battery means working with your tools longer. In addition, Lithium Ion batteries do not show the charging peculiarities of Nickel-based batteries. You do not need to babysit the charging process. You can just set it to charge and go without needing to worry about damage from overcharging or incomplete discharges.
Yet another advantage of Lithium Ion batteries for power tool is that it is lighter than the Nickel-based batteries. Lithium Ion batteries have high energy densities which means they pack more charges per any given volume. Lastly, Lithium Ion batteries are easier to make in different sizes and shapes which is why some manufacturers now put them into the handles of the tools to save space and provide balanced hefts.
However, Lithium Ion batteries have their demerits too. For one, placing them in the handles of power tools means that to replace a battery you will need to send the whole power tool back to the manufacturer or have it shipped to repair centers. In addition, except you plan on buying new power tools, there are few Lithium Ion batteries fitted to go in your old models.
Therefore, the first step in buying a replacement battery for your power tool is finding an exact fit with the same power ratings. It is not necessary to buy a replacement battery from the same manufacturer just as long as you can guarantee the quality of the replacement. However, where the old battery served well, it is advisable to buy the same as a replacement if you can find it. You can either take the old battery along when looking for replacements or note down the model number on its casing.
Batteries are rated by their voltages and capacities. Therefore, expect to know what volts and ampere-hours the replacement battery you intend to buy are rated in. Of these two, ampere-hours is more important since it determines how long the battery will last. However, the higher the voltage and ampere-hour of a battery, the longer and stronger the power tool will perform. Batteries usually come in ampere-hours of 1.4, 2.4 and 3.0 amp/hr ratings. You can find these written on the battery itself.
Another consideration to have when choosing a replacement battery is the charging time. It is impractical to have a cordless power tool that needs to be charged after every hour of use and that takes long to charge. The advice is to go for a battery that last longer in use and that charges faster so that it can be re-used as soon as possible.
You can buy your replacement battery at a dedicated tools shop or from online stores. Online, you can order from the websites dedicated to homeowners and professional users. Here, you will find a broader range of batteries to choose from and at more favorable prices. Some buyers prefer to buy from the big brands in the market e.g. Makita, Bosch etc. Generally, batteries from these manufacturers are known to perform well but they may also be more expensive. You should consider shopping for batteries that are rated high by previous buyers and users like you regardless of what brands they are just as long as you are sure the batteries are the right fit for your power tools.