This week a reader writes in: “If I was going to look at buying a refurbished laptop, is there any simple way to determine the state of the battery? I know it is not going to be a new battery, but is there any way to tell if it is on its last leg?”
The answer is yes, you can get a look “under the hood” and see some battery statistics that are not visible in the regular operating system control panels or under the battery menu.
On a Mac, you go to the Apple menu on the upper left corner, click and pull down to About This Mac.
You’ll get a small dialog box of information about the Mac, but this doesn’t include the battery data.
For that, you’ll need to dive a bit deeper.
On the About This Mac Overview screen, you’ll notice a button at the bottom that is labeled “System Report.”
Press that button, and the MacOS will generate a report on all sorts of system information.
In the report, on the left, scroll down and select “Power” to display the battery information, which includes the battery condition (it should read “Normal”), the number of charge cycles on the battery (lower is better) and the number of milliamp-hours (mAh) the battery is holding along with the original full-charge capacity.
For instance, my Macbook Pro at work shows normal battery health, 55 charge cycles on the battery (it should last at least 1,000 cycles) and a full charge capacity of 7,030 mAh. The current battery capacity at 100% charge is 6,399 mAh.
The report can also let you know whether the battery is fully charged or still charging. You can read more about Mac batteries at https://support.apple.com/en-us/HT201585.
On a Windows laptop, you’ll need to go to the Start button (lower left), scroll the program list to Windows PowerShell and select it and launch PowerShell.
You’ll see a new window appear with a flashing cursor called a command prompt.
PowerShell is an app programmers use to run commands and programs.
You’ll want to type the following command at the flashing prompt: powercfg /batteryreport /output “C:\battery-report.html” and then hit the Enter key on your keyboard. This command asks PowerShell to run a battery report and save the output as an HTML file called battery-report on the root level of your C drive.
PowerShell should tell you the report was saved. Then you can open your C drive from the Windows File Explorer (right click on the Start button to launch the File Explorer) and double-click the file called battery-report.html to launch that file in a browser.
The report lists more information than you ever knew existed about your laptop’s battery, including the designed capacity, maximum current capacity and cycle count.[object Object]