Are sealed-in laptop batteries a good idea?

When Apple Inc. introduced its new MacBooks recently, it touted a doubled battery life -- but noted that the laptops' batteries were sealed into the case, not user-swappable as is the norm with laptops.

The MacBook Air and the Dell Adamo knock-off of it also use sealed-in batteries, but the MacBook Pros are the first mainstream laptops to take this leap. Given Apple's influence on PC makers, sealed batteries may become more prevalent. Is that such a good idea?

[See how long your battery lasts with InfoWorld's battery life calculator. And read how InfoWorld debunks 10 power-saving myths.]

At first blush, the idea of a nonremovable battery in a laptop seems ill-advised. After all, batteries are absolutely key to laptops, and everyone has had a laptop with a battery that just won't hold a charge, requiring you to be no more than five feet from an outlet. In most cases, it's simple to buy a new battery and install it in a few seconds.

Why sealed-in batteries trouble users and IT

The most common complaint about having a sealed-in battery revolves around situations like traveling on a long-distance flight or waiting in an airport lobby where no power plugs are available -- when even a five-hour battery might not be enough to get you through. In those cases, having a spare battery in your bag can mean the difference between finishing the report you're writing (or the movie you're watching) and having to entertain yourself with the final 30 minutes of Bride Wars on an off-color overhead screen.

Sealed-in batteries can also be a problem for those who work in remote locations -- such as war zones -- where wired power may not be readily available. In extreme cases, the ability to swap batteries in such situations can mean the difference between life and death.

More prosaically, sealed-in batteries create a hassle when a battery fails, since the laptop must be returned to the vendor, causing significant delays for users and requiring IT to manage more overhead (in the form of spare laptops). Likewise, some batteries can swell over time, and if the battery is fixed into the computer, it could damage sensitive parts.

So why seal batteries in at all? Given the potential problems, why would vendors seal in batteries?

Simply put, if a laptop manufacturer doesn't have to worry about a removable battery compartment, the design of a laptop is simpler. Without the inset for the battery, the connectors, the catches, the support frame, and so on, a battery can take on different physical forms and be larger than it would be if it had to be removable. That means there's less need to design around the battery's shape and location.

Also, without the need to accommodate the battery case and the separator for the battery compartment, the laptop becomes slimmer and lighter -- even though the battery itself might be bigger. These are not minor trade-offs, especially if you have to constantly lug a laptop around an airport.

Another fact to consider is that today's laptop batteries are far more advanced than those of just a few years ago. The old nickel-cadmium batteries were slow to charge and prone to "battery memory" problems that arose if you weren't careful to fully charge and discharge them (essentially limiting how many times you could juice them). Because the batteries took a long time to charge, you likely needed to swap between two batteries, so one could charge independently. And the fact that the older batteries could only be charged a limited number of times meant you would likely have to replace a battery during the time you owned the laptop. In both cases, you needed to be able to easily remove the battery.

But today's batteries, such as the lithium-polymer cells in the MacBook Pro, charge quickly and can handle a much greater number of charge cycles. That lessens the need to swap out batteries -- Apple is counting on that to be true, claiming that the batteries will be good for at least five years, which is longer than vendors expect most people to keep their laptops.

The combination of modern battery technology such as lithium-polymer and the greater capacities made possible by sealing them in also reduces the need to swap out a battery in flight.

How to handle the legitimate challenges that sealed-in batteries pose

Still, the risk remains that a battery fails or you need it to run longer than it is capable of. A sealed-in battery leaves you stuck in both cases.

Or does it? You may not be able to swap out a dead battery for a charged one in flight, but you can still use an external battery to power the laptop. These external batteries connect to the laptop's power jack, and are roughly the same size as a spare internal battery.

Sanho, for example, sells such batteries for MacBooks; and these batteries also let you plug in USB devices, such as iPhones. They connect via a power cord, so you don't need to place the external battery right next to the laptop (which would be impossible on most airlines' tray tables). The lowest-capacity version costs $200, or $40 more than the equivalent Apple internal battery. Battery Geek offers a similar product that works on a variety of PC and Mac laptops.

When batteries fail or swell and need to be replaced, it can be trickier to deal with them. Typically, you send the laptop back to the manufacturer to have the battery replaced, often at no charge. (In the case of a swelled battery, which is often caused by water intrusion, the laptop may be damaged and need further repairs or complete replacement.) In a business environment, that means IT will need to keep a few spares on hand, so it can loan one out when a laptop with a failed battery is being repaired.

A better option may be to swap out the failed battery with a working one from another laptop, so the user doesn't suffer much of a delay. Despite being sealed in, the batteries are often user-removable. It's true that Apple requires that battery replacement be conducted by Apple-certified technicians, but in reality, replacing a battery in a MacBook Pro or MacBook Air requires only a #000 Phillips screwdriver and a few minutes at best. And once you've replaced the battery, you could theoretically put the one that failed into one of your spare laptops and send it to Apple for repair -- but you'd have to hope that Apple doesn't notice the swap and refuse to replace the battery because you've voided the warranty. If you're friendly with an Apple tech, you might quietly inquire about how Apple would treat such warranty "flexibility."

Why I'm comfortable with sealed-in batteries

My own experience with laptops leaves me at ease with the idea of sealed-in batteries.

I bought a spare battery for my two-year-old 17-in. MacBook Pro a month after I got the laptop, because I was about to fly across the United States. But it's fairly hard to drain a battery of that capacity on a transcontinental flight, and I never did break out the spare on that trip. To this day, it sits unused on a shelf in my office.

I also own an original MacBook Air, the first Mac with a sealed-in battery. After 18 months of daily use and 325 cycles, the battery capacity is down to 94%, but it still lasts nearly three hours on a full charge. I haven't needed more time than that, even on long flights. If I did, I'd get an external battery and be done with it.

My Dell D800 is another large laptop that has the original battery -- and no spare. The lack of a spare for that laptop has never been an issue, either, and I use laptops like they owe me money.

I also know that if the sealed-in batteries are not up to snuff, the manufacturer is on the hook for battery replacements that are costlier than just shipping a new battery to the user. So they have a strong incentive to make sure the technology works.

Given today's technology, it should make no difference whether the battery is user-replaceable. The benefits of current battery technology -- extended runtime, weight reduction, and better overall design -- simply outweigh the occasional need for a spare battery. And the few users who do need spare batteries can get an external one.

If Apple's and Dell's forays into the use of sealed-in batteries are successful, don't be surprised to see more manufacturers join the club.

This story, "Are sealed-in laptop batteries a good idea?" was originally published by InfoWorld.

Copyright © 2009 IDG Communications, Inc.

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