win 7 shutting down laptop at 50% battery

I have a brand new battery in an Acer travelmate 5720. It has a BRAND NEW battery in it. at 50% power, the laptop dies as if the battery is totally drained. Will not even post to bios. Just dead.
I adjusted the settings for the battery in windows to alert and shut down the computer at 50% to save whataver data is there, but this is not a good fix. There are no settings in the bios for adjusting the battery. What is going on in windows to cause this?
I've read thru the threads and saw a lot of people with this problem only to be told that it's their battery or the laptop, and blah blah blah. Anything but Windows 7. I'm going to insisit that this problem is definitely caused by windows.

yes I think alot of ppl here are backing up windows 7 but YES it is probably a windows 7 problem because ALOOOOOOOOOOOOOOOOT and when I say alot i mean thousands of ppl are saying it's a windows 7 problem because, most Battery problems occur AFTER the installation of windows 7, my problem is that it drains alot of power it use to have 3hrs battery life after installing windows 7 BAM! 15 mins of battery life it made my Laptop a Desktop computer now and I don't think it's when your computer is turned on because I also noticed that when my laptop is turned off and after like 8-10 hrs it would already be unable to boot up so now what i know is that It screws up battery life it's most likely NOT in the system but windows does something to the laptop's battery. a solution for the broken computer NONE
the solution GET A WINDOWS 7 LAPTOP THAT THE DEFAULT OS IS WINDOWS 7 thats the only fix available. this problem is very common AFTER the installation of windows 7 so I'm sorry microsoft but you kinda screwed up somewhere here

cluberti said:

The problem is, the battery IS drained. If you can't power back on, the problem is that the BIOS, the firmware, or the battery itself is misreporting the amount of juice in the battery. Windows 7 reads battery information from the BIOS slightly different than previous versions of Windows, so if your battery "dies" at 50% and you have to plug it back in to get your laptop to boot, the problem is your system components misreporting charge when queried, not a Windows "bug" or issue. The system is misreporting the charge when queried by Windows, and that's where the fix has to come from - either a BIOS or firmware update, or indeed the battery is faulty.

Windows 7 Battery Notification Messages - Engineering Windows 7 - Site Home - MSDN Blogs

For what it's worth, my wife's laptop (1.5 years old) started doing this last month, and after the hardware manufacturer of the laptop came out and tested the battery it was indeed determined that the battery itself had reached it's end-of-life and was not holding a charge properly. The battery itself was reporting to the firmware incorrect information, which caused the system to report to Windows incorrect information, which caused Windows to report incorrect information.

I realise I'm resurrecting a dead thread, but this is for the benefit of anyone else who stumbles upon this thread like I did. I'm going to have to disagree with the above. I *just* did a hard drive swap on my Acer, installing Win7 Ultimate on the new hard drive. Prior to installing Win7 Ultimate (I had been using Win7 Home Premium on my last hdd), I had no battery problems whatsoever. But with this new install, I suddenly crash at 50% battery. I replaced my battery 3 months ago (it couldn't hold charge even for an hour) and have had no problems with it with my last OS, nor with any "misreporting" of battery information. It is absolutely a Win7 issue in some cases, especially since there would be little reason for Win7 Home Premium to read my battery correctly and Win7 Ultimate to not be able to do the same thing.

When I first got this laptop, it used Vista. I upgraded to Win7 almost immediately and experienced no problems with it. But a sudden upgrade to Win7 Ultimate makes my battery read wrong, and you think it's a firmware or malware issue? Nothing changed on my computer at all, except the hard drive and the OS. Prior to installing the new OS, absolutely nothing was wrong with my computer. My battery, firmware, and everything else had no problems whatsoever communicating with Home Premium until I switched to Ultimate and I have had issues since.

Whatever the dysfunction is, it came with this Ultimate install. I'll be going back to my Home Premium and enjoying being able to use my brand new battery and my computer that was okay until then.

cluberti said:

The problem is, the OS subsystem code that's responsible for power management doesn't change between any SKUs of Windows 7, so when you upgraded to Win7 Ultimate none of that changed. If it's working in one install and not in another (and we're talking about the installation being on the exact same hardware as well), the only difference would be things that could be different - apps, drivers, etc. Windows itself, as far as the innards, isn't different between Home Premium and Ultimate - only additional tertiary features like the ability to run the licensed XP Mode or use features like Bitlocker or Applocker. There are a whole host of SKU differences, but the Windows subsystems don't change.

It's intriguing that upgrading to ultimate caused you this issue, but it won't be Windows-specific - it's going to be something else that's the explanation.

It is very interesting. The only thing I can think of is somewhere in the installation, something went wrong. I'm going to try re-installing the OS. Everyone's suggestion (everywhere) is to replace the battery. For some people, the issue is that it does, in fact, need a new battery. But mine is less than 3 months old and on Home Premium I could use my computer for a good 2 hours before it completely died. Now I can use it all of maybe a half hour before it's down to 50% and crashes. I'm changing my power setting to warn me when it's near 50%. Kind of aggravating though.

windude99 said:

Go to support.acer.com and find your laptop model. Next, you need to go to the section called BIOS and see if there is a new bios update for your system. There may be some Windows 7 incompatibilities with your current bios.

Been there already. There is one BIOS update, but actual Acer owners say it's not an upgrade and flashing the BIOS causes problems on my particular system with cool boot and a few other things so I haven't committed to it yet.

The other thing I can't figure out is why my BIOS would be incompatible with Ultimate, but worked fine with Home Premium.