The Ultimate Battery for Power Tools

by Gregor Halenda Gregor Halenda

The Trend

Companies are rolling out lithium- ion cells-old hat in mobile phones-with enough juice to feed amp-hungry power tools.

Why Now

Engineers have tweaked the
li-ion recipe and added circuit boards that monitor cells to prevent batteries from exploding.

How You'll Benefit

Li-ion tools offer 40 percent more power per pound than those using nickel-based batteries.

Lithium is the lightest and most energy-dense metal on the periodic table, making it the best power source for portable batteries. But it's also highly reactive (think: fire)-not the kind of thing you want to push beyond its limit. At least not until now. Engineers have cooked up li-ion batteries that remain stable even when your saw screams into a pine knot, along with new circuitry that defuses runaway reactions. Although the batteries are pricier than their
nickel-based predecessors, they hold their charge longer and don't lose capacity after repeated charging. So you get more bang for the buck-without the, well, bang.

The mighty drill for close quarters

The right-angle head is mounted on a 360-degree
swivel, making it easy to operate between wood joists and studs when boring for electrical or plumbing lines.

Maximum torque 1,081 in.-lbs.

Maximum speed 1,000 rpm

Weight 10.9 lbs.

Battery 28V li-ion

The lightweight saw for big jobs

The powerful motor's copper-impregnated carbon
brushes last for an impressive 100 hours before wearing out, and they can be replaced up to five times.

Maximum speed 3,700 rpm

Blade diameter 6.5 in.

Weight 7.1 lbs.

Battery 18V li-ion

The always-ready junk-drawer driver

The slow self-discharge rate of this palm-size electric screwdriver's built-in battery means it'll be fresh when you blow the dust off it a year after charging.

Maximum torque 48 in.-lbs.

Maximum speed 180 rpm

Weight 0.75 lbs.

Battery 3.6V li-ion