Notes on comments.
Welcome to our blog dedicated to the engineering of Microsoft Windows 7
Over the past week we have seen a little bit of blogosphere activity regarding Windows 7 and batteries, specifically the new Windows 7 message “Considering replacing your battery”. Since this is related to the engineering of Windows 7 we’re going to use this blog to provide an update to people. As we have talked about many times, we have a relentless focus on the quality of Windows 7 and we take seriously any reports we receive that indicate a potential problem that could result in a significant failure of the OS. In a previous post we talked about the steps we take when we receive a bug report, in particular when we start to see several reports that appear to be the same. For the past week or so we have been diligently working through these steps and more to see if there is anything in Windows 7 we need to address regarding this issue. At this time we have no reason to believe there is any issue related to Windows 7 in this context.
Several press articles this past week have drawn attention to blog and forum postings by users claiming Windows 7 is warning them to “consider replacing your battery” in systems which appeared to be operating satisfactorily before upgrading to Windows 7. These articles described posts in the support forums indicating that Windows 7 is not just warning users of failing batteries – as we designed Windows 7 to do this – but also implying Windows 7 is falsely reporting this situation or even worse, causing these batteries to fail. To the very best of the collective ecosystem knowledge, Windows 7 is correctly warning batteries that are in fact failing and Windows 7 is neither incorrectly reporting on battery status nor in any way whatsoever causing batteries to reach this state. In every case we have been able to identify the battery being reported on was in fact in need of recommended replacement.
Using all the tools at our disposal including contacting customers reporting this issue on forums, customer service communications, partnerships with our PC makers, and of course the telemetry in Windows 7, we have been monitoring reports and discussions regarding this new feature, trying to separate reports of the designed behavior from those that might indicate an issue with Windows 7. In the latter cases we are trying to understand the scope of applicability and obtain hardware on which to reproduce a faulty behavior. To date all such steps indicate that we do have customers seeing reports of battery health issues and in all cases we have investigated Windows 7 has simply accurately detected a failing battery. Before I go into our status on this particular issue, we should review the details behind this new feature.
One of the most obvious components of PC battery life (the runtime you get on battery power) is the battery itself. PC batteries inherently degrade in their ability to hold a charge and provide power (as is the case for all rechargeable batteries). The cause of this is complex and includes irreversible changes in battery chemistry, and increased internal resistance among other things and those in turn are dependent on the design and manufacturing of the battery. This degradation translates into less battery life for the user over the life of the battery in the PC. Ultimately, batteries must be replaced to restore an acceptable battery life. A quick check of mainstream laptops will show that batteries usually have a warranty of 12 months, which is about the length of time when statistically we expect to see noticeable degradation (meaning that you start to notice the need to charge more frequently). Those of us that have owned the same laptop (or mobile phone, or music player, or anything else with rechargeable batteries) for a couple of years and taken it through regular charge cycles have no doubt “felt” the decline in battery life though we might have attributed to any number of factors since we did not have any information available to us otherwise.
Windows 7 makes use of a feature of modern laptop batteries which have circuitry and firmware that can report to Windows the overall health of the battery. This is reported in absolute terms as Watt-hours (W-hr) power capacity. Windows 7 then does a simple calculation to determine a percentage of degradation from the original design capacity. In Windows 7 we set a threshold of 60% degradation (that is the battery is performing at 40% of its designed capacity) and in reading this Windows 7 reports the status to you. At this point, for example, a battery that originally delivered 5 hours of charge now delivers, on average, approximately 2 hours of charge. The Windows 7 the notification is a battery meter icon and notification with a message “Consider replacing your battery”. This notification is new to Windows 7 and not available in Windows Vista or Windows XP.
PC batteries expose information about battery capacity and health through the system firmware (or BIOS). There is a detailed specification for the firmware interface (ACPI), but at the most basic level, the hardware platform and firmware provide a number of read-only fields that describe the battery and its status. The firmware provides information on the battery including manufacturer, serial number, design capacity and last full charge capacity. The last two pieces of information—design capacity and last full charge capacity—are the information Windows 7 uses to determine how much the battery has naturally degraded. This information is read-only and there is no way for Windows 7 or any other OS to write, set or configure battery status information. In fact all of the battery actions of charging and discharging are completely controlled by the battery hardware. Windows only reports the battery information it reads from the system firmware. Some reports erroneously claimed Windows was modifying this information, which is definitely not possible.
As mentioned, every single indication we have regarding the reports we’ve seen are simply Windows 7 reporting the state of the battery using this new feature and we’re simply seeing batteries that are not performing above the designated threshold. Below we’ll talk about the data we have to support this point of view. It should stand to reason that some customers would be surprised to see this warning after upgrading a PC that was previously operating fine. Essentially the battery was degrading but it was not evident to the customer until Windows 7 made this information available. We recognize that this has the appearance of Windows 7 “causing” the change in performance, but in reality all Windows 7 did was report what was already the case.
This data would confirm our point of view that we are seeing nothing more than the normal course of battery degradation over time. The transparency provided in this new Windows 7 feature produced a notice that previously was not available to customers and did so shortly after upgrade. This is the root cause of the urgency with which we’ve seen postings, but does not change the reality of the condition of the battery. We have no confirmed cases of new machines with the as-purchased batteries.
As we always say with regards to any reports on the quality of Windows 7, we are going to continue to be diligent and use all the tools at our disposal to get to the bottom of a report that has the potential to require a code change we would distribute to customers. We are as certain as we can be that we have addressed the root cause and concerns of this report, but we will continue to monitor the situation. In particular, we will continue to have focused communication with our OEM partners as they monitor their customers and PCs over time.
Finally, if you believe you are receiving this error and your battery is new or believed to be in great shape we would encourage you to report this to us or your original PC maker. You are welcome to send me mail through the contact form on this page, use the TechNet forum, the Microsoft Answers forum, or visit support.microsoft.com where you can get additional information about how to contact Microsoft assisted support in your region.
I have seen posts on Technet with new machines that have Windows 7 factory installed.
Threads galore pop up daily. I have suggested as a work around, remove the battery and be a desktop until a fix surfaces.
Depending on temperature li-ion batteries should last least a few years.
My old 2004 camera needed a new battery because the capacity degraded to under 50% of max capacity. The new battery brings the device back to life.
I have read where some have bought a new battery and the problem was still evident.
I swapped my 6 cell battery (that died completely, won't recharge) for my son's 9 cell battery (exact same computers - Dell Inspiron 1520) he bought a new machine. It is working so far, recharging to 100%. Fingers crossed.
I have gigabyte U60 my battery is 6 months, when full charged(100%) it last 25 min. and reach 1% win 7 shut down and I plug my charger just for 5 sec. to power on when OS starts battery is 0% and then u60 work 1 h and shut down permanently, Then if I charged him powered off my battery indicator when it is charged start blinking (what whose normally on xp) but if I charged it when power on in win 7 it charges 100% and indicator lamp just shut down. So Win 7 definitely control my charging and stop charge before it is full charged battery.
P.S. It is not win 7 design machine but everything works fine except battery and M$ pleas give as an options to chose what acp battery control we wont xp, vista or new win 7.
My System is approx 2 yrs old. The system when installed with Windows 7 did not report the battery needing replacement and in fact ran fine for some time. It was after making a change to the power settings that the message appeared. When the battery is removed and self tested it shows 100% power, no degredation. Microsoft Windows 7 support members have suggested a BIOS upgrade since one of the updates that was applied after the initial install was believed to be the cause. Is this a valid statement?
Stop complaining about windows 7 which does a great job in detecting your stupid old PC
Buy a new machine!!
Just did the so call upgrade to Win 7 Ultimate on 2 laptops. First dv9000 reports "plugged in not charging" and was pefectly charging before. HP DV4 reports "consider changing your batter" and was the battery was great before hand. Should have known better considering Microsofts' history with its previous OS versions. I'll contact Steve so he can add this to the list with his companies ad campaign.
Guys, get over it. Microsoft cannot (and will not) admit to causing this problem. Why? If they did, they will be the ones responsible for replacing every single battery destroyed. From a business's perspective, this means $$$ loss and Microsoft cannot accept this.
Microsoft says that it is not possible to modify the batteries and destroy them because they were read-only. You do not need to modify battery data to destroy it. All you have to do is either overcharge it, or drain it too much to degrade it. This is something that can be easily done with faulty programming or incompatibility with some motherboards.
Also, there were wayyyy wayy more than just 20 people having this problem, as reported on this blog. From one blatant lie, you can expect to know more exists within the same article.
Expect this post to be deleted...
I think George is right because my acer 5738 is just one year and 12 days old and its warranty just lasts 29th sept 2010 and today 11th of oct. my windows 7 ultimate show me that "considering replacing battery" msg. How can this be possible? just after 12 days of warranty ends...
same issue here... and this problem seems to have surfaced on the net for over a year by now. Microsoft should do something... seriously...
at least come up with an update to fix this issue, so that even if i do buy a brand new battery, that IT WON'T HAPPEN AGAIN... jeez...
All this text is just a lot of bullshit! I used to have a battery working during 2 to 2,5 hours before to install Windows 7 (I used to have a Windows Vista Home Premium OEM installation at my Toshiba Satellite U305-S7448) and now my battery works for 20-30 minutes only. Hey man...Microsoft, as usual made a lot mistakes. Please correct that as soon as possible.
Come on Microsoft! 18 pages of responses so far and I too have the same problem. New Acer laptop was fine on Vista and within a few weeks on Windows 7 the system shuts down with critical battery level after 5 minutes. If I disable the ACPI driver it lasts nearly 2 hours before a hard shut-down. There MUST be a problem with Windows 7 and surely you can do something about it before someone fires up a class action case.
After reading the whole thread and search on net, seems there is no solution and all and Microsoft is just not interested to look into this.
Mine is window 7 home edition on HP d640 (10 months old lappy). the prob started all of sudden a week back. Even after full charge it displays a msg "100% charged, consider replacing your battery" and battery run time has been reduced to 10-15 mins from 2 hours.
Tried the given solution, but all in vain
Wondering if there is any fix!
"You may incorrectly receive a "Consider replacing your battery" warning message on some older HP notebook computers that are running Windows 7"
When this can happened on HP notebooks then on other notebooks, Why not?
I think this is a programming bug that cause degrade battery faster and Microsoft doesn't want to accept it. MICROSOFT just accept this mistake and release a update or patch so that our new battery live longer.
Steven, We have an 11 month old Dell Inspiron that has just developed this problem. There has been no upgrade it came with 7.
The laptop has so far had to have a new HD and last week a new motherboard and screen. The techs who came and fixed it went away without re connecting the speakers. Is it just co incidence that this has occurred within a week of him taking the lap top apart???
Not a technical person. Does it need a new battery or is this just a message we can turn off....
I just got this notification on my Toshiba Satellite M505-S4940 laptop and have had it for about a year. It was originally Windows Vista then I upgraded it to Windows 7. I haven't had any physical problems with it since I bought it and the battery has been holding it's charge pretty good. About 2 hours depending on which settings I have it on. I'll go to where I originally got it and see what they can do about it.