Windows 8 and 10 both include a hidden “Battery Report” feature. Generate a report to see health information about your battery, how its capacity has decreased over time, and other interesting statistics.
This battery reporting feature is built into the
powercfg command, so you’ll have to pop into Command Prompt or PowerShell to run the command. We’ll be using PowerShell in this tutorial, but either works just fine. You can also use powercfg to generate an energy report, which gives you recommendations for ways you can reduce your computer’s energy usage and extend its battery life.
Generate a Battery Report
The actual battery report you’ll be generating is an easy-to-understand web page file. You just have to run a single command to create it.
First, open a PowerShell window. Press Windows+X and choose “PowerShell” from the Power User menu.
At the PowerShell prompt, type the following command, and then press Enter:
This command saves a battery report in HTML format to the following location:
Just head to your user directory in a File Explorer window and double-click the file to open it in your default browser.
Read the Battery Report
The battery report is a single HTML page, divided into a variety of sections. The first section tells you the name and product name of your computer, the BIOS and OS build version, whether the PC supports Connected Standby, and the time the report was generated.
The “Installed Batteries” section shows you information about your installed batteries, and you’ll only see one battery on most devices. Battery information includes the name, manufacturer, serial number, and chemistry type of the battery.
The most important details here, though, are the design capacity, full charge capacity, and cycle count numbers.
For example, in the screenshot above, you can see that the design capacity of the battery is 44,400 mWh, while the current full charge capacity is 37,685 mWh. This is a result of the normal wear a battery experiences over time, and it lets you see just how worn down your battery is. The battery was originally designed to hold 42,002 mWh, but now has a maximum of 40,226, meaning it holds a little less charge than it used to. For reference, the laptop we used was about five years old. This number will continue going down over time as you use your battery and put it through more charge cycles.
Note: If you have a new device, it may actually have a higher current full charge capacity than its design capacity. That number will decrease over time as the battery chemistry changes.
The cycle count number in the “Installed Batteries” section shows you how many charge cycles a battery has been through. A full charge cycle is measured by 100% battery drain. So, a cycle might be a full discharge from 100% to 0%. Or, a full cycle could be discharge from 100% to 50%, a charge back up to 100%, and then another discharge down to 50%. Both of those count as a single cycle. Batteries can only handle so many charge cycles, and different batteries are rated for different numbers of charge cycles.
The “Recent Usage” section of your battery report displays the device’s power states over the last three days. You can see when your device started, when it was suspended, and how much battery capacity drained over time. The capacity remaining is displayed as both a battery percentage and a number in mWh.
The “Battery usage” section offers a graph that shows how your battery drained over time. Both this and the “Recent Usage” section display data for the last three days only.
The “Usage history” section shows your battery’s usage and duration over time. You can see how much time the device spent on battery power and how much time it spent plugged into a power outlet. The statistics here go all the way back to when you originally set up Windows on the PC—possibly to when you purchased the device.
Battery Capacity History
The “Battery Capacity History” section is also interesting. You can see how your battery’s full charge capacity gradually decreased over time compared to its design capacity. Like with the above section, the statistics here go back to when you originally set up Windows on the computer.
Battery Life Estimates
The “Battery Life Estimates” section displays an estimate of your device’s average battery life for different time periods, based on how you actually used it. Interestingly enough, it compares observed battery life at the device’s full charge to theoretical battery life at its design capacity.
For example, the most numbers displayed in the screenshot below show that the device managed four hours and forty-six minutes of battery life at its current full charge capacity, but that it would have managed four hours and fifty-eight minutes if the battery was still at its design capacity.
Details like this one can help you decide when it’s time to replace the battery. If the difference is drastic, you may want to get a new battery for your laptop or tablet.
The battery report doesn’t provide any instructions or recommendations, as the energy report does. However, the in-depth information about your battery’s capacity over time will help you get an idea of your battery’s health and understand whether you need to replace it or might in the future.
Image Credit: Intel Free Press on Flickr