One of the useful Windows 8 features for notebook/tablet owners is the opportunity to check the battery health using Windows built-in utilities. With this data, you can learn, how the battery is used, how worn it is, if it needs to be replaced and predict its lifetime. This information can be especially important for the users of notebooks with the reduced battery life or in case of buying a used device.
In Windows 8, the Battery Report can be generated with the Power Configuration Utility.
Start a command prompt as an administrator and enter the following command:
The Power Configuration Utility has to generate a report file and save it as battery_report.html, located in the current user profile (C:\Users\(user-name)\battery_report.html).
Let’s open resulting report file (battery-report.html) in any browser and consider it in more detail.
In the first section of the report there is some general information about the system and the battery (the info is mostly referential). More important data can be found in the Installed batteries section. The following parameters are relevant for the user:
- Design Capacity is set by the manufacturer and means the maximum capacity of a new battery (in mWh)
- Full Charge Capacity contains the information of the current maximal capacity of the fully charged battery
- Chemistry is the type of the battery, in our example a lithium-ion battery (Lion) is used
- Cycle Count is the number of full cycles of charge and discharge (up to 100%) of the battery, the cycles when the battery has been discharged to 50% and charged again also fall there.
It’s obvious, that the closer is the value of the Full Charge Capacity to this of the Design Capacity, the better, and vice versa. In our example, you can see that the notebook battery capacity reduced from 38 mWh to 32 mWh during its operation, i. e. the wear of the battery after a year of work is about 16%.
The following report contains complete information about all previous charge and discharge cycles starting from Windows install date. When the system is reinstalled, all the data are lost.
There is also some information about the expected lifetime of the system at the charged battery in the Battery life estimates section of powercfg report. Of course, you should understand that the estimation is quite approximate and depends on the power profile used in the system and the current load.
By the way, this time is displayed on the battery icon in the system tray.
And finally, here are some simple tips that allow to extend the lifetime of a notebook battery and increase the time of its standalone operation:
- It is recommended always to fully charge and discharge NiCad or NiMh batteries. The matter is that these batteries are likely to have a «memory effect» – a gradual capacity loss due to the incomplete charge/discharge of the battery.
- Li-Ion batteries are not subject to the memory effect, but they hardly bear low temperatures. So try to use these batteries under low temperatures as little as possible.
- Li-Ion batteries should be trained from time to time. To do it, discharge and charge it fully approximately once a month.
- It is not recommended to leave the laptop on a full charge plugged in for a long time, because battery from it wears out much faster.