Don't know exactly what prompted it but the battery would not charge above 64%, no matter how I changed the settings of the power saving mode.
Here's how I solved it:
- Power off
- Remove the battery
- Restart Windows
- Go to Control Panel -> Hardware and Sound -> Device Manager
- Under Batteries, remove all Microsoft AC Adapter and Microsoft ACPI-Compliant Control Method Battery
- Power off
- Put the battery back in place
- Restart Windows
Thanks to nickscomputerfix!
On the contrary, a good reason not to keep it charged at 100%:
The third tip relates to when and by how much batteries should be charged. One of the more widely known aspects about battery life is the “memory effect”.
In older rechargeable battery chemistries, such as nickel cadmium, partial charging and discharging significantly decreases the energy capacity.
What is less known is that the memory effect in lithium-ion batteries, if it exists, tends to be very small. Instead, they have quite nuanced characteristics. When not in use, batteries degrade most when fully charged. So if left for several days or weeks without use, they should ideally be kept at a relatively low charging state, e.g around 20% charged.
Conversely, when being charged and discharged a lot, it is best to keep the batteries as close to the 50% mark as possible. So if you are only charging and discharging batteries a bit at a time, it is much better to do this between 45-55% than between 90-100%.
Full article.