Windows 7 includes a new command that shows you a lot of details on its power usage & settings and helps you troubleshoot power issues (like Windows 7 waking up unexpectedly when you’ve put it in Sleep mode).
This command also shows you some detailed information about your laptop’s battery, including its design capacity and the last full charge. With this data you can calculate how much (percentage-wise) your battery has deteriorated over time. Let’s have a look:
- Click Start button and type cmd in Search programs and files box
- Right click on cmd.exe listed at the top of the Start menu and click Run as administrator
- In the command prompt type cd %userprofile%/Desktop and press Enter
- Next type powercfg -energy in the command prompt and press Enter, powercfg will enable a trace for 60 seconds. If you want to use it for more information than just the battery details, make sure no other processes are running during that time
When finished, powercfg will generate a report (in html format) which shows errors, warnings etc. Since we directed the command prompt to your desktop, the report will be placed on your desktop as energy-report.html.
Just open the report in your web browser & scroll all the way down to the Battery Information section.
|Battery ID||53883 2013/04/03Hewlett-PackardPrimary|
|Serial Number||53883 2013/04/03|
|Last Full Charge||47941|
This test was done on my HP Laptop 6470b (yes we sell them) the design capacity of my battery is 47941 & the last full charge is the exact same amount which means the battery is like new – which it is.
If the last full charge was say 40% of the design capacity that would = 28765. From experience I’d guess that this battery will only last maybe a few months more.
Full Charge Capacity refers to the maximum capacity of the battery at the present time. It will slowly decline with age and use as the batteries ability to hold a charge decreases. “Charge remaining” refers to the current state of the battery.
Laptop batteries have a voltage rating (V) and milli-Amp hours (mAH) rating, and they’re multiplied together to come up with the milliwatt hours capacity. Following Design Capacity is the Full Charge Capacity, which represents the amount of charge that the battery will actually hold.