back to article Microsoft tests show no Win 7 battery flaw

Microsoft says that extensive testing and conversations with OEMs indicate that Windows 7 is handling notebook batteries exactly as intended - despite user claims that upgrades to the new OS have caused significant degradation to battery life. As we reported in late January, various laptop owners - including a string of …


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  1. Captain Save-a-ho
    Black Helicopters

    May not be battery-specific flaw

    There's several sites that have reported that Win7 uses more power than Vista and XP on the same hardware, based on additional features intended to maximize the user experience. If there's not a batter-specific reason, people should be aware of the difference in draw.

    Having used 7 for the past 6 months and Vista for the two years before that, it sure seems to that 7 took a step backward in power management. Even the time required to sleep seems exceesive, compared to Vista on the same hardware (laptop and desktop).

    Guess this means MS, IBM, HP, Dell, Sony, etc. are all in cahoots to sell more batteries.

    1. Adam Azarchs

      Not a general Windows 7 flaw, either

      Lots of changes were made to the kernel and services in windows 7 which significantly improved battery life for most people. A few people might have config problems, but I'd put good money on most people who report these problems finding their battery life in windows 7 much better than in XP or Vista, if they dual-boot.

      Certainly in XP at least I've found most of the batteries sold with big-name laptops die after a year or two. Certainly no more than that. Some of them (a four-letter word starting with D) even put re-certified batteries in new laptops, and then have their 3 or 4-year warranty only cover the battery for one year in the fine print.

      As far as Microsoft's involvement, I'd say don't shoot the messenger, until you're sure the messenger is actually at fault.

  2. Henry Wertz 1 Gold badge


    Yeah, I'd buy this. I mean, people will claim equipment is "new" because it's only several years old. Unfortunately, a lot of batteries are crap and will be on the way out in just a year or two. The other factor is these computers that will fast-charge the battery in like 45 minutes or something.. this drastically shortens the life compared to slow-charge systems (which are virtually non-existent now) that would take maybe 3-4 hours to charge. This is anecdotal, but I had a P2 Gateway that was nearly 10 years old, and held around a 50-60% charge. it took hours to charge the battery. The newer Dells I've seen, they seem to get to a 50% charge within 2 or 3 years.

    The big test really is to boot some other OS (OSX, or XP with a battery life monitor, or Ubuntu, etc.) and see what the battery life estimate is? Does it agree with 7? OK, your battery is shot and XP or whatever didn't tell you. Does the number disagree? Then 7's battery monitor is faulty as people have claimed.

    1. James O'Brien
      Thumb Up

      You know

      I would actually agree with you on the battery fast charge issue. I know they rate Lion batteries for (what is it 300 duty cycles?) but have they ever done a fast charge discharge repeat cycle?

      All good points you made. Would like to see a study on this.

    2. jackharrer

      Who needs a title?

      Actually in Linux you can access all battery statistics straight in one text file. You can see how much capacity originally was available, how much is left, current power draw/charging, etc.

    3. Gulfie
      Thumb Up

      Slow charging

      Apple still slow charge their batteries. My MacBook Pro is two years old and with daily use both on and off the charger the battery is still showing over 95% of original capacity.

      When run down to near empty the battery takes a couple of hours minimum to fully charge, and when I was in Europe last week it took forever because, I'm guessing, of the lower voltage mains input.

      1. SJB

        Lower voltage?

        Eh? Europe has a lower mains voltage compared to where now?

      2. Lord Elpuss Silver badge

        Lower voltage?

        Except for the fact that in Europe we use 220/240V as opposed to the 'Merkin system of 110V.

      3. styx-tdo



        240 is lower than 120?!!

        1. Anonymous Coward
          Anonymous Coward


          I think he means that continental Europe's 220V is lower than th UK's 240V. However this will make sod all difference to the output once it's been stepped down and regulated.

    4. Anonymous Coward
      Thumb Up

      My results...

      OSX and Win7 stats for my battery are almost identical and actual battery life is very close to the predicted life in both cases so no issue here.

      Win7 can stand a little tweaking to the 'default' power profile to improve battery life, it would be interesting, however, to do a side-by side test with Vista and Windows 7 with identical settings / load... anyone?

      Anal Tester

  3. Anonymous Coward


    Bing Bang goes the eco-credentials?

    Bing Bing goes returns on battery maker shares?

  4. Orclev

    Dud batteries?

    Maybe part of the problem is also people buying dodgy "new" batteries from Chinese suppliers? It could very well be that their "official" battery is a cheap knockoff that really is putting out less than 60% of its claimed capacity and this new monitor is essentially tipping people off to the swindle.

    1. Anonymous Coward

      Dodgy replacement batteries

      I wholly agree on that. I have a HTC TyTN whose battery generally degraded after 3 years of heavy usage. Having budget issues at that time, I bought a no-brand replacement battery (well, actually, Sanyo-brand replacement battery. Still Made in China tho) for it.

      The first one died completely within 4 days.

      Since it's still under warranty, I took it in to have it replaced. The second one still delivers, but is showing signs of degradations very fast. Right now it's 6 months down the road and the battery is already struggling to last over a day.

      These batteries need better QC...

  5. Watashi


    Laptop batteries often don't last more than a couple of years before they significantly lose capacity. Quite often, batteries die quite quickly. If several million people suddenly upgrade to Windows 7 there will be several thousand who find their battery life is reduced simply because the battery has coincinetally died at the same time. Not only this, but Vista's battery life measurement isn't that great anyway, so perhaps some of these are just cases of correcting problems.

    Having said thet, a Microsoft OS with no problems at all would be a bit weird.

    If people do find their battery life being sucked out faster than they like, there are a few options in the advanced section of power settings that can help. You can limit max CPU rate, for example.

    1. Allan George Dyer

      ... or install Linux...

      Sorry, I tried to resist, but the temptation was too great.

      Flames, because it is the other things batteries are well-known for...

  6. jim 45


    Maybe the key weasel-word is "recommended". Is Win7 using new replacement guidelines issued by the Laptop Battery Manufacturers Association? Ok I made that up but you get the point - maybe these new 'recommendations' are just a wee bit conservative?

  7. Anonymous Coward
    Thumb Up


    Running "powercfg energy" from an elevated command prompt will give you, among other things, the battery's design (new) and current capacity.

  8. wibbilus maximus


    "The OS then calculates how much this figure has decreased from the capacity provided by the battery's original design specs"

    Could it be that the information on the original design specs is faulty/corrupted? If the original design specs data that Windows 7 accesses indicates a battery life to be twice what it should be then Windows 7 will report a failing battery even if said battery is brand new.

    Anyone know where Windows actually gets the information on the original design specs? if it's held in an internal database then it's possible the information is wrong or has been corrupted somehow.

  9. Iain Thomas


    Sounds like they're just accessing data that's available via ACPI. Linux tools (like cat /proc/acpi/battery/*/info) have been able to do this for a while now. It would seem a fair guess that a number of these issues are just the ACPI code returning bogus data. Because there's no point fixing it because windows doesn't use it... Well, it does now, and affected people might do well to check for BIOS updates for their machines, and see if any of the changes mention battery statistics...

    Then again, they could be right; rechargeable batteries fail gradually, and humans seem to be quite excellent at not noticing gradual changes. This particular attribute does not bode well for battery powered electric cars which will, one day, have just not quite enough power left to get one all the way home...

  10. Monteeth

    Check your processes

    Everyone who has this problem I recommend downloading Process Explorer here:

    look out for constant low level CPU activity of 3 processes - dwm.exe (Desktop Window Manager), SearchProtocolHost.exe, SearchFilterHost.exe. Also keep an eye out for dllhost.exe when browsing folders in Windows Explorer- it seems there may be a bug in W7 that can cause the search and thumbnail to indexes to constantly delete and refresh themselves, which is obviously going to be bad for battery life......

  11. uninventiveheart

    OK, how?

    It's nice to get these warnings and all, but most modern laptops that are cost-effective (cough, netbooks) DO NOT HAVE replacements sold. If your battery is skunked, you're stuck with it.

    1. Anonymous Coward
      Anonymous Coward

      Some do...

      My Acer Aspire One has three replacement battery options, 3, 6 and 9 cell.

    2. Anonymous Coward
      Anonymous Coward

      Re: OK, how?

      "most modern laptops that are cost-effective (cough, netbooks) "

      Did I miss a meeting?

      Say a netbook sells for £200, and a dual core laptop (200, maybe 300% more powerful in terms of raw CPU power alone) sells for £300 (only 50% more).

      I know which I'd choose to be the cost effective option.

  12. Flocke Kroes Silver badge

    Before blaming the battery manufacturers

    Try disabling bluetooth and wifi. Inadequate EMC suppression can make battery monitoring chips give false readings. Some charger chips include a timer to make absolutely certain the battery is never over charged. Preventing the timer from activating when a radio transmits is challenging (much easy to use a chip without a timer, and use an external time source). If the timer stops the charger early, monitoring software will think the battery has reached its maximum charge when it has not had enough time to get close to full capacity.

  13. JamesKew35

    Weird speculation here..

    What people are missing is that this is not anything to do with bad batteries, or increased power draw of windows 7 or processes. The issue is that windows 7 corrupts the information stored on the batteries. My laptop ran fine with windows vista, the battery died within a week of a clean windows 7 install. This was a healthy battery, low cycles.

    Got a replacement battery, installed vista and had no issues. We Ran windows 7 on it but only without being plugged in, then recharged by booting a ubuntu live cd. This arrangement worked and the battery was fine after 3 weeks. We then started letting windows 7 charge the battery and the battery was dead within a few days. Read the technet and you can see this duplicated over and over again.

    Now, at work we did a transplant of the cells from the second battery to a third and guess what.. It works fine! We're working to start logging windows 7 interaction with the battery to collect evidence for a class action atm.

    You wonder why microsoft is trying to downplay this? Imagine the recalls..

    1. PaulW


      [Quote] windows 7 corrupts the information stored on the batteries [/quote]

      Can anyone explain this part to me? Am I really missing something?

      I thought APCI was read only. I was unaware that anything could write back to an APCI device? (Maybe its done by using some funky quantum mechanics during the charge cycle to set electron spin orbits or something?)

      And if I can write to the battery, how much storage can I get on a battery? Could I use it to store my collection of umm fine art images for extra portability?

    2. Anonymous Coward
      Thumb Up

      any blog or website to track your findings?

      Do you have a blog or some such that people like myself can use to track your findings and then specific on the potential class-action lawsuit you're looking to start? My wife's lenovo ideapad y550 has seen less than a month of use and the battery went dead (win7 says "plugged in, not charging").

      As a Linux software engineer I immediately thought windows7 was at fault ;) It's comforting to know my gut feeling was seemingly accurate.

      The first replacement battery shows up tomorrow. I think I'll get Fedora 12 running on this lenovo and just use KVM (virtualization) to run windows (if at all). At this point my wife is open to all solutions (including "we should get in on that class action" :)

  14. Anonymous Coward
    Thumb Down

    Luddite justified!

    I've always thought that laptops were a compromise too far, and along comes another vindication of this opinion.

    Don't get me started on netbooks...

  15. S 10
    Thumb Down

    The hardware is junk

    I've not upgraded to Win7, but have to say that the quality of laptop batteries seems to have been in general decline for a long time. My <1yr old HP lap now holds a charge for about 10 mins (no kidding). Compare that to my 5 year old HP machine which still manages about 2hrs40.

  16. Geoff Mackenzie

    collective ecosystem knowledge


  17. tempemeaty

    I see bubbles....

    Something look a little fishy? People do notice before-and-after differences in things. Give it some months and I think the truth will begin to show what is really going on here.

  18. mkc

    They lie

    I understand that Win7 may draw more power to do the same things as Vista. But if I switch off all the fancy stuff in Win7 and plug in so my battery gets 100% charge, the charge vanishes in minutes, I get the Consider replacing yoru battery pop up and then the laptop shuts off.

    If I reinstall Vista again the battery lasts for hours, how can simple things in Win7, like just running the OS and a Web Browser draw the battery to empty in minutes? How are netbooks coping that have smaller batteries?

  19. JC 2

    C'mon Now, This Is Windows

    Since when was MS really expected to release an OS that did not usurp more resources than predecessors? It's not a flaw it's a design feature. Surely your whole computing world revolves around buying new hardware to run Windows, and run windows as much as possible so damn the expense you need a new battery, then a new PC, because you can't buy too many windows licenses.

  20. Anonymous Coward

    If it was "previously running fine"

    then I'd suggest that their warning is, at best, scare-mongering.

    "We recognize that this has the appearance of Windows 7 'causing' the change in performance"

    So there is a perceptible change in performance then, which happens just around the time you install Windows 7? What a coincidence.

    Windows 7 does a lot of irritating things (it's a shame, because it's otherwise a very stable OS). It refuses to work with most DVI KVM switches, because it's doing something that previous OSs didn't do. Microsoft's fix? Spend another $200 on a new KVM. Gee Bill, thanks.

    I thought those who said they'd wait for the first service pack were silly - now I agree with them.

  21. The BigYin

    Simple answer for MS


    Add the module (through Windows Updates) to XP and Vista, then people can see for themselves if this is "caused" by Win 7 or not.

    How about a Reg-Off? Unscientific I know, but two new lappys; same model, same specs. One with XP (or Vista, if you must) and one with Win7. Then use a scripting to tool to run through the same operation repeatedly until the battery paps it.

    As for batteries....any good with a soldering iron? Pop the battery open (it's often LiOn AAs or similar inside), note down the serial number of whatever is inside, order new ones, unsolder the old, solder in the new. So long as you have a reasonably steady have (and a multimeter to check connections...) you should have a new battery pack for better than half price. Heck, if you know your electrickery, you might find a way to "upgrade" the battery.

    Reminds me...I have a laptop I need to do that to.

    1. Peter Gathercole Silver badge

      2 laptops?

      Why not just 2 hard disks? One with Win7, the other with WinXP. Do serial checks, one with the XP disk and one with the Win7. Repeat, and see whether anything changes.

      Cheaper on hardware, but possibly more time consuming.

  22. John Smith 19 Gold badge
    Thumb Up


    Thanks for the pointer. It's good to see someone offering some constructive help. Your comments suggest that Windows 7 is a *monster* battery hog and the battery app is just reporting the fact.

    The help file is rubbish.

  23. KroSha
    Paris Hilton

    The problem is user education

    I regularly see people who complain that their battery is fritzed. The vast majority have never ever run a calibration process, or even run the battery all the way down. And most run their laptops on their desk, permanently plugged in to the mains. So they have no concept of how long a charge actually lasts, and they are frying the battery as well.

    Paris knows how long her batteries last.....

  24. Anonymous Coward
    Anonymous Coward

    I think MS are right on this one

    I recommend people have a read of Zen and the Art of Laptop Battery Maintenance at

    Oh and to the guy saying Win7 "uses more power" - not in my experience. It may well "use more power" than XP but it uses considerably less than Vista on the same hardware - the 64-bit version at least. I suggest you have a LONG HARD look at how your power management is set up.

    Good point from Iain - there's a lot of very broken ACPI implementations out there.

  25. Anonymous Coward
    Thumb Down

    After 6 months I think Win7 is horrible.

    Microsoft help isn't helpful. MS Access still has blank entries for some of it's errors, and has done since 2003. Either they haven't considered the problem or their search facilities are lacking, knowing 'bing' I think the latter. Excel and word are barely able to find basic help files, so complex coding in Excel has little chance without google and some useful MVP out there with a blog.

    Microsoft answers don't help. I have yet to be told why my speakers and headphones don't work at the same time, but do for XP, Vista and Ubuntu. A nice lady in India has gone quiet.

    And Win7 is horrible for all kinds of reasons, like my usb keyboard that takes a minute after reaching the password screen before the base unit gives it power enough to actually type in the password. (It works fine for BIOS, and works fine in the other OS I have used. So win7 removes the power to the USB and then gives it back during boot)

    And why does it still take 19 hours ( I kid not ) to copy 200MB from HDD to flash pen. And take five minutes to work out the 19 hours. Some things from Vista still carry over.

    And now every time sleep mode comes on, the machine crashes because I use SLI. Hardware support my rear end.

    How anyone can put that laggy bunch of rubbish onto a small form factor netbook and get it to work is beyond me. I have never used it's "battery useage" tools, but all the whistles and badly put together bells don't hold out confidence in a limited resource platform.

    Choose a penguin, ubuntu 9.10 works fine on my asus eee 1000, and the MAC OS-X works nicely so I have seen.

  26. Tarthen

    You mean....

    ...Windows' battery meter actually WORKS now?

    (In every laptop I have had, the XP/Vista battery meter would jump around worse than the times in the file copy dialog.)

  27. Roger Garner

    Two Acer Laptops...

    ... one 3 years old - still has the same 1.5 hour battery life under 7 it had under Vista.

    The other 1 year old oddly has an extra 30 mins life under 7 compared to Vista... considering this is the 8930G 18.4" beast that never had more than 2.5 hours when brand spanking new I'm naturally far happier under 7 than Vista from that point alone :p

  28. Anonymous Coward
    Anonymous Coward


    Cheap and nasty laptop - meet bloated OS.

  29. James 47

    I love it

    The Lin-tards all uppity about Windows' battery consumption. So... how come it took so long for Linux to make it on to a mobile phone??? It wouldn't have anything to do with the fact that it just sucked the battery dry? Check out the battery life on an N900.

  30. Anonymous Coward
    Thumb Up

    7 year old laptop, Athlon64 3200+ on its 3 battery.

    Hi, be thankful Windows 7 is reporting battery life problem. Generally a battery under 70% charge capacity should be replaced in critical equipment like medical equipment. Microsoft is recommending it at 60% which is fine for laptops. Or would you rather your battery fail in the middle of a important presentation, etc? Most people can ignore the warning like I do, until it won't turn on in battery mode...

    1. frymaster

      threshold value for "consider replacing..." dialog

      "Generally a battery under 70% charge capacity should be replaced in critical equipment like medical equipment. Microsoft is recommending it at 60% which is fine for laptops"

      actually it's at a _degradation_ of 60% i.e. only 40% of capacity

    2. Jess--

      The title is required, and must contain letters and/or digits.

      that is the point, you cant ignore the warning since windows 7 turns the laptop off for you when it thinks your battery should be replaced.

      I currently get around 3 hours use out of my laptop, when it reaches the point that it only lasts 2 hours because my battery is aging I will still find that acceptable since windows xp or vista will warn me at different intervals that the batter is running out (20% & 3% if memory serves)

      now throw windows 7 into the mix and it spots the fast drop (from what should have been 100% charge but is in reality around 60% because of an old battery) and it decides your battery should be replaced and shuts down (even though you know there was at least a further hour or more of life in the battery)

      by all means let me know that my battery has aged and can no longer hold more than 60% of its proper charge, just let the laptop run as normal afterwards and use the normal warning levels for when to shut down.

  31. Simbooth

    new possiblity

    Looking into it, I have seen it suggested that, for example the 88.8Wh reported for my laptop is the capacity of a larger battery;is it possible that as the information has never been used up to now, that manufacturers have simply been using one set of firmware for all of the different capacity batteries? And just changing the amount of cells? I must admit at first I was also quick to blame MS, but it does seem a very likely scenario if they were trying to reduce manufacturing costs. Cant say that that makes me happy though.

  32. Eradicate all BB entrants

    lalalalalalalalalalala i cant hear you

    first off @ AC who thinks Win7 is horrible, why the hell are you blaming it for Access issues? Secondly ...try running it on something better than a Cyrix welded to a pc chips board.

    Now for the serious stuff. Laptops manufacturers have been classing batteries as 'consumables' for years. Consumable means they want you to buy at least a few over the life of the product they are put in. I remember when Dell launched the updated D series Latitudes .... feck your were lucky to have a battery that lasted 6 months and then when you reported the thing was dead they wanted you to buy a new one. Took hours of shouting to get it replaced under warranty. Any new battery is now designed to last just over a year so you have to buy a new one.

    As for the whiners, learn about the equipment you are using. If you charge from less than 30% (i think) while using the laptop you may as well pop it out and take a lump hammer to it. As some of the later posters have pointed out, run the laptop until the battery is fully discharged, then plug in the psu and leave it powered off until the battery is charged. Doing this once a month will make the battery last longer.

    Dont blame MS for the poor implementation of hardware technology by the manufacturers.

  33. ZenCoder

    Score one for Windows 7

    Windows 7 is just making users aware that batteries do in fact have quality control issues like any other product and that some wear out sooner than others.

  34. jbabybulldog
    Thumb Up

    I haven't noticed a change

    I haven't noticed a change in my laptop battery life, but I have a friend who just bought a brand new Gateway and immediately her battery meter says 7% battery life. When she plugs it in to the power adapter it doesn't change, still shows 7%.

    Btw great blog I'm in a class where we are learning to create blogs and yours is the first site I found that had interesting useful information. Thanks

  35. Wortel


    I´d like to see their so called results and compare them to the rest of the world. NEW batteries being reported as ´degraded´ by win7 smells like a software issue. I have yet to find, after 8 years and 44 notebooks with 32 more on the way within the next 3 months, a DEAD factory installed battery. I have only replaced 4 batteries just this week because capacity was below 30%. only 4 after all these years.

    1. steve 44

      Bigger sample size requried......

      I've found dozens of dead "new" batteries in laptops. Then again, I was a laptop engineer for about 4 years so i've seen hundreds if not thousands of the bloody things. Maybe you need a bigger sample size........................

  36. Graham Wood

    Wonder if I should check mine properly.

    I've got an "oldish" laptop that W7 tells me has a dead battery - and within 5 minutes of shifting to battery it turns itself off. I'm pretty sure that XP would run for > half an hour...

    Will try an ubuntu liveCD and see what happens.

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