The case of the mysteriously shrinking laptop battery

We just reviewed a new retail-specific versionof Dell's popular Inspiron 1525 laptop, and found ourselves wondering why this new system's battery life was so poor compared to its very recent (and largely identical) predecessor. How can two versions of essentially the same laptop have a difference in battery life as big as the 3-hour vs. 2-hour one we found? We looked a little closer and found a potential culprit.

Both $650 laptops (the newer 1525-139Band the older 1525-121B) have six-cell batteries, but that's not always the most useful number to look at. Most laptop batteries are labeled for 56Wh (or watt hours), which means they can hypothetically power a 1-watt load for 56 hours. The 1525-121B had a standard 56Wh battery, while the 1525-139B has only a 41Wh battery, which one would never notice without taking the battery out and reading the fine print stamped on it--as the batteries (and systems) look pretty much exactly the same.

Thus, our shorter battery life, and one more area where budget-minded PC makers are apparently trying to shave a little cost from their systems. So the lesson here is that there's now one more bit of fine print you need to read carefully before buying a laptop.

Read the full review of the Dell Inspiron 1525-139B here.

Note the two different Wh ratings on these Dell 1525 batteries.