Extend the life of your laptop’s battery

Fred langa By Fred Langa

With proper care and feeding, the expensive lithium-ion batteries in your notebook PCs and other portable gear can run well for many, many years.

On the other hand, common battery-care mistakes will reduce your batteries’ run times and lead to needless and costly early replacement.

The care and feeding of laptop batteries

A reader named Rick got a new laptop for the holidays and is wondering how to maximize the life of its expensive batteries:
  • “I just got a new laptop with Windows 7 for Christmas. The new laptop has a 6-cell lithium-ion battery. How can I get the most life from my new laptop’s battery and make it last the longest?

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    “Should I periodically charge and then use/drain the battery? Should I leave the battery in the laptop even when I’m using the AC plug? Will heat from the laptop when it’s plugged into AC affect the lithium battery?”
Excellent questions, Rick!

Heat is the enemy of lithium-ion (Li-ion) batteries. When your laptop runs on AC, it’s smart to remove the battery pack and store it in a cool place. Low temperatures forestall the inevitable and irreversible chemical changes that occur in Li-ion batteries.

In fact — and this will sound odd — if your laptop is mostly run off household AC power, you can greatly extend the life of its Li-ion battery this way: Run the battery down to about 40% of maximum charge, remove it, and store it in a tightly wrapped plastic bag inside your refrigerator! Storage at about 40 degrees F (4 to 5 degrees C) is ideal. Think of it as the 40-40 rule: 40% charge, 40 degrees F.

If you can, avoid running Li-ion batteries all the way down. Early portable electronics used nickel-cadmium batteries, which benefit from full discharge cycles. Conversely, Li-ion batteries last longer when kept in a charge state between 40% and 100%. It’s OK to run Li-ion batteries flat when you have to, but the ideal scenario for longest life is one full discharge cycle for about every 30 or so partial cycles.

Sad to say, even if you’re perfectly careful with your Li-ion batteries, they’ll slowly go bad on their own due to their irreversible and inevitable chemical changes. This is one of the main reasons why cool storage helps preserve Li-ion battery life: the cool temperatures slow the chemical reactions.

Even a well-maintained Li-ion battery will usually show signs of age two or three years after manufacture. That’s why it’s not a great idea to buy a second or spare battery for your laptop unless and until you really need to use one. If you buy a spare you don’t really need, it’ll slowly go bad on its own, giving you no (or reduced) return on your investment.

If you do have a spare battery, store it in the fridge with about a 40% charge when it’s not in use.

When you buy replacement batteries, check the date of manufacture. This will usually be stamped or printed on the battery case. Cut-rate, bargain batteries may have been sitting on a warehouse shelf for a couple years, meaning that a good chunk of their useful life has passed before you ever plug them in.

With careful use, you can get 300 to 500 charge cycles from a new, high-quality Li-ion battery — especially when the battery’s stored in a cool location when it’s not in use. You should get years of good service from such a battery. With just a little luck, by the time the battery no longer holds a useful charge, you’ll be ready for a new laptop, anyway!

These two excellent articles provide more information on Li-Ion battery life:

How to prolong lithium-based batteries from BatteryUniversity.com

The care and feeding of Li-ion batteries from TechRepublic.com

What’s causing the ‘event ID 51′ disk errors?

Jack Lavelle’s hard drive is generating tons of “event ID 51″ errors in his system log:
  • “Can you guys take a look at this and tell me whether my XP system’s hard drive is going bad, or what?”
Figure 1 is the screen Jack sent along with his e-mail.

Numerous event id 51 errors
Figure 1. Jack’s system log lists literally dozens of “event ID 51″ errors, a handful of which are shown here.

Unfortunately, “event ID 51″ is nonspecific. Microsoft refers to it as a “generic error” in MS Knowledge Base article 244780, “Information about event ID 51.” Such a mild, generic error message suggests this isn’t a serious problem.

I suspect your disk is powering down when not in use. When the OS makes a call to the sleeping disk, the disk needs to spin up before responding. This timeout delay is probably the cause of the generic errors reported as “event ID 51.”

If my hunch is correct, the solution is to lengthen the time before your hard drives turn off. See the Microsoft article, “Configure Windows XP power management,” for instructions.

If changing the drive’s standby time doesn’t work, Microsoft says, you can troubleshoot event ID 51 errors by following the same steps outlined in KB article 154690, “How to troubleshoot event ID 9, event ID 11, and event ID 15 error messages.”

You can also check more directly on the drive’s mechanical health via the Self-Monitoring Analysis & Reporting Technology (SMART) feature that’s built into most modern drives. SMART data is stored within the hard drive itself and often can alert you to impending problems before they get serious.

Many hard-drive monitoring tools can access and display the SMART data. Two tools I like are PassMark DiskCheckup (info and download) and Active@ DiskMonitorFree (info and download). Both programs are free for personal use and also come in commercial versions for organizations.

Should I use Safe Mode for routine maintenance?

Joe Cervenka sent two questions in one e-mail. Here’s the first one:
  • “I recently came across two tricks and wanted to know whether they’re safe to use on my Windows XP computer. The first involves using Safe Mode to run various scanning programs (AVG antivirus, CCleaner, Smart Defrag, etc.) Do you have any feedback about this?”
Safe Mode is a kind of bare-bones Windows. In Safe Mode, your diagnostic or maintenance activities can proceed without the interruptions or interference that might be caused by the full complement of drivers and software that Windows normally loads.

That said, it’s probably overkill to use Safe Mode for minor maintenance tasks such as routine antivirus scans and normal disk defragmentation. On a healthy PC, tasks such as these run fine in your normal operating environment. But if you run into trouble — say, you have malware you can’t get rid of or your defrags are taking forever — booting into Safe Mode may help set things right.

Need help accessing Safe Mode? The oddly name BleepingComputer.com site has a good Safe Mode tutorial that applies to all versions of Windows.

Does a ReadyBoost flash drive really boost?

Here’s Joe’s second question:
  • “As for the other computer trick, a friend mentioned using a flash drive for ‘paging.’ What is paging? Is using a flash drive better than using the computer’s own HD for paging?”
Your friend is referring to ReadyBoost, a technology built into Vista and Windows 7 that can use a flash drive as a kind of extra scratchpad memory. Windows stores memory in chunks called “pages” — hence the “paging” terminology.

I don’t recommend ReadyBoost. Flash drives wear out after a finite number of write cycles, so it seems questionable to use flash drives in a high-wear activity such as supporting a pagefile. Even worse, real-life tests show little or no speed benefit from ReadyBoost. So why bother?

If you still want to give ReadyBoost a shot, you’ll find more information in my June 25, 2009, column, “Use ReadyBoost and pagefiles on flash drives?”

What’s this about Windows 7′s ‘God Mode’?

Jim Bennett heard about a reputed “God Mode” for Windows 7:
  • “Don’t know if you folks found this already. Came across it on a Facebook post from a friend. Pretty neat way of getting to everything one might need to work on Windows. The trick is posted [on the IThinkDifferent site].”
The “God Mode” trick is real — sort of — but it’s seriously misnamed. All it does is give you a very large, alphabetic list of Control Panel tasks; no more, no less. You can’t do anything in God Mode that you can’t also do by accessing Control Panel the normal way.

There’s a nice explanation of this and other “shell folders” for Win7 and Vista in an article on the Windows Valley site.

Amusingly, the “God Mode” name is actually irrelevant. You can name the folder anything you want, and it will work exactly the same way. If the original posts had called it “Idiot Mode,” it would function identically, but then no one would want to use it!

God Mode might be useful to those who prefer scrolling a large list to using icon-driven navigation. But just realize that this trick is really not in the least godlike. It’s just a different way to access Control Panel tasks!

Have more info on this subject? Post your tip in the WS Columns forum.

Fred Langa is editor-at-large of the Windows Secrets Newsletter. He was formerly editor of Byte Magazine (1987–91), editorial director of CMP Media (1991–97), and editor of the LangaList e-mail newsletter from its origin in 1997 until its merger with Windows Secrets in November 2006.
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Fred Langa

About Fred Langa

Fred Langa is senior editor. His LangaList Newsletter merged with Windows Secrets on Nov. 16, 2006. Prior to that, Fred was editor of Byte Magazine (1987 to 1991) and editorial director of CMP Media (1991 to 1996), overseeing Windows Magazine and others.