The first cordless tools were invented in 1961 by Black and Decker. The first batteries for the tools took up to sixteen hours to recharge. Now, most recharge in an hour. The cordless tools were a revelation in that they allowed carpenters and construction workers to work freely on the site without having to worry about the location of outlets for power. When buying battery power tools, there is an important consideration to keep in mind: the battery.
Batteries for light duty
If you are going to do work around the house or light construction, then a battery that will work well in this situation are 9.6 volt NiCD, 9.6 volt NiMH or a 10.8 volt Li-ION. NiCD refers to Nickle Cadmium, NiMH refers to Nickle Metal Hydride, and Li-Ion refers to Lithium Ion. Some examples of tools that have these batteries are the Ryobi SA960 drill (9.6 volt NiMH battery), the Makita 6991 wrench (9.6 volt NiMH batteries) and Bosch tools like the Bosch Max I Driver (10.8 volt Li-ION battery). Generally speaking, the NiCD has a long cycle life with 1000 plus cycle changes. NiMH has a cycle life that could be longer than that of the NiCD, but only if it is stored properly. The LiION has a short cycle life and can last up to two to three years.
Batties for medium duty
If you are going to be doing some work that requires a longer lasting battery, then you will need to step up to a 14.4 volt battery. These are available in the NiCD, NiCD and LiION batteries. Some examples of tools that have these batteries are the Porter Cable 978 Drill/Driver, the Makita 5094D and the Hitachi CR24DV reciprocating saw.
Batteries for heavy duty
When you need a tool to perform for long hours on the job site, then you will need a battery that will discharge its power more slowly. Batteries that would meet this challenge would be the 19.2 volt NiCD, the 24 volt NiMH, and the 24 volt Li-ION. Some examples of tools that have these batteries are the Porter Cable 826 drill with the 19.2 volt NiCD battery, the Hitachi CR24DV reciprocating saw with the 24 volt NiMH battery, and the Rigid R883 jig saw with the 24 volt Li-ION battery.