Cordless tools enter a new era

New battery technology and more efficient motors take cordless tools closer to replacing corded tools on jobsites.

Three things dominate workers’ wish lists for cordless tools: Longer run time, lighter weight and more power. It’s been the mantra of nearly every tool user interviewed by manufacturers since the first cordless tool went to work on jobsites.

In 20 years, cordless tools have transformed from underpowered curiosities to tools that have enough power to twist the heads off fasteners. Nickel-cadmium (Ni-Cd) batteries are the most popular power source for these tools, but a new battery technology – lithium ion (Li-Ion) – may very well take users closer to cordless tool nirvana. These new-generation tools have longer run times, enough power to run truly heavy-duty tools and, on top of all that, lighter weight.

While Li-Ion technology is not likely to completely replace Ni-Cd and nickel metal-hydride (NiMH) systems anytime soon, the new technology is turning heads.

“The lithium-ion technology looks good,” says Doug Bock, Panasonic national sales manager. “It promises increased run time, greater power and less weight. I predict every tool manufacturer will have it in their line-up within the next year.”

Milwaukee Electric Tool is the first company to introduce the Li-Ion technology in construction-grade cordless tools. Its new V28 28-volt Li-Ion battery system, introduced in early February, is now on store shelves and sales are brisk.

“The response has been phenomenal. We sold half of what we forecasted before it was even available. Workers who have tested the new technology say that it finally pays off on the promise cordless tools made 10 years ago,” says Tom Smith, Milwaukee group product manager.

Lithium-ion technology
Several tool manufacturers independently report they are working on Li-Ion platforms for power tools; however, DeWalt officials prefer to keep their cards close to their chests. “We are always evaluating new technology that includes everything from the tool mechanisms to battery technology,” says Christine Potter, senior product manager for cordless tools at DeWalt. “Our research is application-driven and our strategy is to expand into applications that were once considered corded tool-only categories.”

Makita sources say it is a two-step process designing Li-Ion battery system that exceeds the demand of heavy applications as well as designing a charger that effectively chargers a Li-Ion battery. “We still have a firm belief in the Ni-MH platform and have introduced the new MXT line of tools. Ni-MH keeps the tool running longer with less time spent in the charger. We also know professional tradespeople are willing to pay a premium if the performance is there,” says Brent Withey, Makita brand marketing manager.

Based on Milwaukee’s reports, Li-Ion batteries can deliver about twice the run time as Ni-Cd tools with no power fade until the very end of the discharge cycle. Volt for volt, the battery cells are lighter, so a Milwaukee 28-volt battery pack weighs slightly less than an 18-volt Ni-CD battery pack. Plus, it has micro-circuitry that manages charge and discharge cycles.

The Li-Ion technology does not appear to be as sensitive to cold weather as Ni-CD battery packs. Researchers report the Li-Ion packs will do almost four times as much work in below-freezing weather than a Ni-Cd pack.

While Milwaukee’s system is a new platform, others report they are developing battery packs that will work with their present 18-volt tool line.

“Li-Ion technology is here and it will work,” says David Smith, Metabo executive vice president. “The challenge is to get the batteries to discharge at the right pace. The battery packs we are working on are 2.0 amp-hour and 3.0 amp-hour capacity. Their main benefit is less weight, which will weigh 40 percent less than present Ni-Cd and Ni-MH battery packs.”

Smith predicts Metabo will offer the new batteries as an accessory to its cordless tool line by the end of the year. “The battery charger will be able to charge all types of our batteries and is designed to pull air through the battery pack and the charger to cool components as they charge. Heat is the enemy of every battery pack,” he says.

Perhaps the biggest downside to the new technology is price. Milwaukee’s V28 tools came on the market priced about 50 percent higher than the street price for Ni-CD tools.

"Combo kits continue to be very popular and at an excellent price. Contractors have invested into their respective battery systems for a long time. It will be interesting to see how willing they are to change, especially as Ni-CD development continues," says Jeff Wilkison, cordless product marketing director, Bosch Power Tools. "When looking at any battery platform, don't forget to keep durability in mind. You should expect your batteries and tools to survive the rigors you put them through."

While the numbers look impressive against Ni-Cd-powered tools, Bock points out that Ni-MH 3.5 amp-hour tools that Panasonic sells offer end-users 50 percent longer run time at a cost that’s very close to Ni-Cd battery pack. “When today’s Li-Ion technology is compared with this Ni-MH battery, there is only a 33 percent run time advantage. Are contractors willing to pay at least a $150 premium for this longer run time?” Bock asks.

Mechanical advances
While Li-Ion technology may be stealing the headlines this year, other significant improvements are coming in cordless tool mechanics that improve efficiency which translates into more power, longer run times and greater durability.

DeWalt’s new cordless finish nailer is the first tool of its kind to use battery power – not compressed gas – to power the tool. “It can fire nails as fast as a pneumatic tool but doesn’t use replaceable gas cartridges for power,” Potter says.

Panasonic continues to build its cordless tool line with the addition of a wood circular saw, a metal circular saw, recip saw and flashlight; however, the greatest advance that Panasonic offers is a new impact tool that provides an electronic readout and control of torque output.

“It’s a three-speed tool where torque and speed can be adjusted electronically,” says Bock. “There is no clutch setting. It is all electronically controlled. Plus, there is a snug-up feature that will turn the bit or socket one-half-turn to snug up a fastener.”

Makita’s new MXT series cordless tools have recently been unveiled, giving the professional user more power, speed and durability and giving the end-user the ability to match the right tool to the application.

“The MXT line of cordless drill drivers uses Ni-MH battery technology and an all-metal gear housing and all-metal chuck. It has a three-speed transmission so users can match the tool’s speed and power to the application. In low speed, the tool can handle up to 3" self-feed bits; the mid-range speed is good for driving lags and screws; and high speed is good for drilling,” says Withey.

The new tools are also easier and less expensive to repair. “Motor brushes can be changed in the field. If you ever have to replace the motor, its two-piece design means you only have to replace the part that’s worn or broken, greatly reducing your costs.

“The rare-earth magnets in the field and the high-grade wire in the windings help produce more power in a lighter, smaller and more efficient motor.

“The tools also have a total-control trigger. That gives you infinite speed control. Other drills use a trigger that stair-steps speed. This tool will give you a smooth ramp-up speed,” Withey says.

The tool can be used as a drill, driver or hammer drill, and will come with 2.6 amp-hour batteries in 14.4- or 18-volt tools.

Published in the May 2005 issue of Contractor Tools and Supplies magazine.

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