Windows Battery Health Step #6: Store Smartly
If you're not going to use your laptop for a while (or you've unplugged the battery and set it aside), you should be careful when storing it.
Remember: Laptop batteries don't like to be at 100% capacity for an extended period of time, and definitely I also don't like having the battery at 0%. To preserve the battery as much as possible, discharge it to about 50% and then turn it off before storing it. (Make sure you also store it in a moderate environment, as extreme heat, cold, and humidity are harmful.)
The battery's power level will decrease over time if it's not stored for a long period, so you may want to take the system out of storage and charge it back up to 50% every six months or so. If you leave it like that for a few years, the battery may go back to 0%. And again, if it's been at 0% for a while, that's bad.