Lithium-ion (Li-ion) batteries already are used in many construction tools, including cell phones, laptops and GPS devices. Because of the popularity of and advancements in Li-ion battery technology, many contractors have decided now is a good time to cut the cord on their power tools.
Cordless power tools are attractive to contractors because they offer independence from fixed power supplies; significant savings on damaged cords; fewer safety risks when operating in elevated and wet conditions; and improved mobility when working on lifts, ladders and scaffolds.
As Li-ion battery technology has advanced, uses for cordless tools now include larger, higher-intensity applications, such as drilling large-diameter holes in concrete, cutting sheets of plywood and performing demolition work with reciprocating saws.
Battery-operated power tools have been available for decades in a wide range of voltages. Sub-compact batteries (12V and less) replace small hand tools commonly used for access into tight spaces, and industrial-grade batteries (14V to 36V) allow professional contractors to quickly drill, fasten, bolt and cut a variety of materials, such as wood, concrete and metal.
The more applications required for the job per day, the more frequently the tool is used. Higher voltages allow cordless tools to be used with greater frequency.
The downside is that the more voltage a contractor needs to accomplish a task, the heavier the cordless tool can get.
Shedding a Few Pounds
Li-ion batteries generally are much lighter than other types of rechargeable batteries because the cells are constructed out of lightweight lithium. The weight of the tool is one of the biggest issues for contractors when switching from corded to cordless power tools.
NiCd (nickel-cadium) battery packs allow contractors to work without the hassle of managing a cord. Usually, though, tools equipped with a NiCd battery weigh a pound or more than their corded counterparts. When an operator is working with a power tool for eight hours a day, those extra pounds can cause fatigue, resulting in lower productivity and a greater possibility of injury.
Li-ion battery technology shaves up to two pounds off the total weight of the tool, enabling contractors to get two times the capacity out of the tool for the same weight.
The motor and gearing system efficiency allows Li-ion battery-operated tools to produce more work per charge. This means more energy is transferred directly to the application and the tool is quieter during operation. It also produces less heat and less vibration—making it more comfortable for the contractor to operate for extended periods of time.
Other Li-ion Advantages
All Li-ion batteries are built with onboard computers that manage the battery’s power supply. Individual cell management ensures the charge is getting to the cells that need it most. It also redirects the power to prevent cells from becoming overused.
A “state of charge” indicator lets contractors know how much energy remains, preventing time wasted going back and forth from the charger to the application.
Additionally, Li-ion batteries have a longer life expectancy than other battery technologies. They can work efficiently for up to three years or more, while NiCd batteries can fail within six to 18 months of use.
In terms of cost, a corded tool looks less expensive in the beginning because it comes with a lower price tag—maybe one-third to one-half of the price of a cordless tool. But, the price tag doesn’t include the cost of extension cords or a generator, which may be needed on an underdeveloped or remote jobsite. All of these extras can easily add up to $600 to $800 per tool.
Also, consider the soft cost associated with owning a corded tool: the labor to manage the cords every day.
In comparison to NiCd batteries, Li-ion batteries cost approximately 30 percent to 50 percent more; however, many users are willing to accept the expense due to the lower weight associated with using a Li-ion-powered tool.