Cheap laptop batteries: Good deal or risky business?

Are they safe? And what about my warranty?

The aftermarket battery trade is a fact of life and will likely grow in the coming years, but that doesn't mean the notebook makers have to like it. I asked several leading laptop manufacturers if they believe aftermarket batteries are dangerous to use and if using them invalidates the notebooks' warranties. While Apple, Hewlett-Packard and Dell did not respond to my repeated queries, Lenovo and Toshiba agreed to discuss the issue.

Neither manufacturer said that aftermarket batteries are dangerous, but they stressed that their batteries were designed and manufactured expressly for their equipment. A Lenovo representative said, "We do not support the use of nongenuine Lenovo batteries in ThinkPads. ThinkPad batteries are designed and tested with ThinkPad notebooks to ensure safety, compatibility and performance."

While using an aftermarket battery doesn't invalidate a notebook's warranty in and of itself, the manufacturers probably wouldn't repair a notebook under warranty that has been damaged by a faulty aftermarket battery, according to company representatives. In other words, a faulty aftermarket battery does invalidate the warranty.

As a Toshiba Corp. marketing executive said to me, "Toshiba does not guarantee the system's performance, reliability or safety as they relate to aftermarket batteries."

This is ironic, since notebook makers like Apple, Dell, Sony, Lenovo, Toshiba and others have an uneven record when it comes to the batteries they sell themselves. Together, they have recalled millions of bad batteries over the past few years. Some of the power packs weren't up to spec, while others were potential fire hazards. So it seems that no battery, regardless of who makes or sells it, is immune to problems.

MacBook Pro replacement batteries.
Click to view larger image.

"Most replacement batteries are perfectly safe," observes Vishal Sapru, manager of power systems at market analysis firm Frost & Sullivan. "But you really need to be wary." His advice is to seek out a reputable dealer with a history of supplying high-quality products that provides a year's warranty on the battery and an initial money-back guarantee.

The reward is that you'll pay between 15% to 50% less than the manufacturer product for substantially the same battery. "In some cases, it really is the same battery," says Sapru. But he warns against batteries listed for less than 50% of the reseller price: "Below that, there's potentially something wrong with the battery and the seller."

Excellent advice is to steer clear of used batteries or those listed on eBay. I wish I had heard this advice five years ago when I bought a battery for my Gateway notebook on eBay for $20, compared with Gateway Inc.'s $150 product. It was listed as a new battery in the original packaging, but it held only a 20% charge, making it worthless to me.

"In other words," explains Laptop Battery Express's DuBois, "shop carefully and be comfortable with your battery purchase. If it seems too good to be true, it probably is."

How I tested

I started by marking each battery so as not to confuse them. After weighing and comparing the fit, finish and color to the originals, I set each up in the notebook and gave it an overnight charge.

BatteryMon at work. Click to view larger image.

I then started up BatteryMon on the ThinkPad R50 and coconutBattery on the MacBook Pro and recorded the capacity of the battery (in milli-amp hours) as measured by the software. BatteryMon also provides a nice visual graph of the battery's charge level, which is helpful in monitoring the test.

Next, I opened a fresh Web window and tuned into the BBC World Service's Internet radio stream via the notebook's Wi-Fi radio. When the system was ready, I unplugged it while starting a stopwatch to measure how long the system ran for. Each notebook was set to three-quarters of its full volume and screen brightness and adjusted not to blank the screen, turn off the hard drive or go to sleep during the test.

I repeated this test three times for each battery and discarded any result that was 15 minutes longer or shorter than any of the others.

Brian Nadel, former editor in chief of Mobile Computing & Communications magazine, is a frequent contributor to Computerworld.