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Benchmark Results: Netbook Battery Life

External Battery Roundup: Stay Away From The Wall Socket
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We expected Amstron's MedXP 300 to lead the pack. Its sheer size suggests lots of battery life. But notice just how far ahead it scores.

Besides the obvious, we have a couple of surprises. Notice that Brunton's Sustain has an output rating of 60 Wh, but comes out ahead of the three ~100 Wh batteries: XP18000, PowerGorilla, and PPU916. This just goes to show that the manufacturer's stated capacity isn't the final word. Voltage and current levels the company uses to test also matter.

Our updated benchmark generates a platform average design power of 11.5 W for the Dell Inspiron Mini 10. We used this value to normalize the capacity of all the batteries tested.

Even though we normalized battery capacity, that doesn't take weight into account. We weighed all of the batteries and graphed capacity and minutes per pound. Similar to normalized battery capacity and battery life, our per-pound metric presents the same data using different units.

While our calculations include the weight of a battery's physical shell, the graph take us by surprise. Pound for pound, Energizer's XP18000 and XP8000 deliver the most battery life. Meanwhile, many of the solutions geared toward industrial use (and consequently employ more durable enclosures) fall to the bottom, including the PowerPad 95 and MedXP 140. Obviously, making a robust battery means using thick armor to protect the battery cells from damage.

The Energizer batteries are the stand-outs here. Compare them to Tekkeon's batteries, which do worse in battery life and have a poorer weight efficiency.

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