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PC World

Battery breakthrough: The 15-hour notebook

August 17, 1999
Web posted at: 10:51 a.m. EDT (1451 GMT)

by Stan Miastkowski

(IDG) -- It's Murphy's law of notebook batteries: Your machine runs out of juice just when you need it most. That is, unless you're carrying a new type of external notebook battery that offers unheard-of stamina.

In PC World's test, a preproduction Electrofuel PowerPad 160 battery ran an IBM ThinkPad 560 Pentium MMX-233 notebook for 15 hours. That's about five times the life of that ThinkPad's standard battery.

Electrofuel's breakthrough is welcome: Fast notebook chips, big screens, and entertaining DVD-ROM drives work great, but they consume power in huge gulps. And lithium ion battery technology, today's standard, was invented in the 1940s.
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Electrofuel has improved lithium ion batteries by using highly efficient packaging and a proprietary chemical process.

Its debut product, the $499 PowerPad 160, is a rectangular, 3/8-inch-thick battery that sits underneath a laptop and connects to the AC adapter jack. The battery will be available only for select IBM and Acer notebooks in September. Electrofuel plans to ship versions for various Dell, Toshiba, Compaq, and Apple portables by late September or October.

Time is on your side

Although the results sound too good to be true, even our most skeptical testers were impressed when the PowerPad 160 extended the battery life of the ThinkPad 560 from 3 hours and 4 minutes to 15 hours and 1 minute. Mileage will vary depending on your notebook and its AC adapter; Electrofuel says that the battery can last for up to 16 hours, but it may also last less than the 15 hours we achieved.

The disparity is due to differences among AC adapters. The PowerPad's 14.8-volt output is lower than the output of some notebook AC adapters. To take optimal advantage of the PowerPad, notebooks need an AC adapter that runs at 16.8 volts or higher. Also, the PowerPad partially charges a notebook's internal battery at the same time it powers the notebook.

There's some overhead involved, so you'll get the best results by removing the internal battery and running the notebook with just the PowerPad. We got the 15-hour result with the internal battery removed. We got 12 hours and 20 minutes of run time with the internal battery in place.

The main disadvantages to the PowerPad are its cost and its weight: a substantial 2.2 pounds (versus 10.6 ounces for the ThinkPad 560's battery). But Electrofuel plans to ship lighter, lower-cost versions in late October or early November. The $199 PowerPad 80 will be rated to last up to 8 hours, and the $299 PowerPad 100, up to 10 hours. These versions should have more broad appeal.

At the other end of the spectrum is the $799 PowerPad 210: This 2.5-pound product, slated to ship in November, will offer up to 21 hours of run time, Electrofuel says.

How'd they do that?

Just how can Electrofuel squeeze so much life from a battery? The PowerPads have more than twice the energy density -- the amount of power per unit of space -- as conventional lithium ion batteries, says Electrofuel vice president David Murdoch.

Up to 22 percent of a standard battery consists of wasted space because of packaging and design requirements, he says. Electrofuel's super-polymer technology dedicates virtually all the space to the battery itself and dispenses with the usual metal package for supporting the battery cells, which can be as thin as 1 millimeter. A proprietary chemical process also helps increase energy density.

Electrofuel is working with notebook makers to produce internal PowerPad batteries, which should debut in portables next year. For now road warriors can relish the PowerPad 160. It's about time someone helped you break Murphy's law of notebook batteries.

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