What is this tag about?
As pointed out in the excerpt, this tag is intended for questions related to batteries on Android devices. Though it might be hard to keep it apart, keep in mind that Android independent phone questions are off topic here according to our help center -- so your issue should have a clear relation to Android.
Some general things
To make it easier for you to avoid the off topic, some generic information on batteries can be found at Wikipedia: Android devices normally use Lithium Ion batteries. So general information on them can be taken from that link. Some other helpful information in short:
- Does constant charging harm my Android cellphone?
- Is my phone liable to explode if I charge it with a charger that came with a different phone?
- When should I start charging my Lithium battery?
- Is there an efficient way to calibrate the battery than using some apps?
Then there's the question about...
- How should I store batteries I currently don't use?
This can be deduced from the Wikipedia article. Basically: Store them half-charged (40-60%), dry, and at the right temperature (0°C..25°C).
- How often should I calibrate my battery?
As few times as possible. Calibrating basically involves running the battery empty (which is not good concerning its health the lower it goes, so stay above 5%), and then fully charge it to 100% in one run without interruption. Considered how often the battery is finished before the day is ended, you probably already do so often enough :) For a sum-up about calibration questions, please refer to Looking for a consistent answer about battery calibration.
See also: How frequently is it okay to let the battery discharge fully or as low as possible?