In Windows 7, there is a little-known feature available from the Command Prompt that will analyze your system, then tell you what power settings you have enabled that may not be providing you with the best battery life for your laptop. It won’t help fix what’s wrong, but can point you in the right direction.
To access this report, first open up the Command Prompt. You can find this in the Start Menu, in the Accessories folder.
This report, however, needs to be run as an administrator, so instead of clicking as normal, right-click, then choose the Run As Administrator option.
Once you’ve clicked Yes to allow the process to run (not shown), the Command Prompt window will appear.
As you can see from the screenshot above, you are running this application as the Administrator, so be careful. You can do damange to your system as the Administrator, although our usage will be quite harmless.
To run the energy report, type powercfg -energy then hit the Enter key.
As you can see from the updates, this report will take a minute or so.
When the report has finished, you can see if there were any errors (there were 0 errors in the report generated above), plus any warnings (only the one), and general information. You’ll also notice that your report has been generated as a simple HTML file. It should be located in the System32 folder, which is inside the Windows folder (located at the root level of your hard drive). The report will be named “energy-report.html” (although you may note see the “.html” if your system is configured to hide file extensions.
Now simply double-click this report to view it in your web browser.
This report will tell us quite a few things about our system’s power saving settings. It shows us where there are problem areas, as well as information that could help us make an informed decision regarding settings that could save energy, and thereby produce better battery life.
The one warning given in this report tells us that our Power Policy for our 802.11 radio (or wireless card), is not configured for low-power mode, which means that when we’re using wireless and running on battery power, we’ll likely use up more energy than necessary because of the wireless card.
Another piece of information users will find helpful is battery life information. Located directly below the CPU Utilization entry in our report is Battery Information.
This doesn’t tell us how long to expect our battery to last but the overall capacity of our battery. In the screenshot above you can see the capacity the battery is designed for, and what it attained during its last charge. Dividing the last full charge by the battery’s designed capacity (48107/48840 in our case), and multiplying that number by 100 gives us a percentage. In our instance, the number is 98.499, telling us that our battery is still able to charge up to almost 98.5 percent of its original capacity (which is good, since the laptop is only a couple months old!).
There are many other bits of info laptop users may find useful in this report. You’ll see what types of sleep states your computer is capable of (likely “sleep” and “hibernate” but possibly others), as well as whether Adaptive Display Brightness is supported. Many of these power settings don’t show up by default in the standard Power Settings control panel, however. Instead, you’ll need to navigate there, click the Change Plan Settings option for your power plan, then finally click the Change Advanced Power Settings option.
This, finally, will bring up the Advanced Power Settings window.
There are many valuable settings here (including the 802.11 power plan mentioned earlier), that should help battery-conscious laptop users squeeze every extra minute of use out of their computer as possible.
As mentioned, running the power report won’t “fix” anything at all. It will tell you what’s wrong, if anything, and areas where you can improve, but ultimately, it’s up to you.