Lithium batteries don't like being fully discharged. My experience though is that after a few charge cycles where you DON'T fully discharge them they should come good again.

Fully discharging lithium batteries on a regular basis is not a good idea. Also, Lithium batteries don't like being left fully charged without use either. If your not going to use the battery within 2 days or so you would be best to only charge it to 80%. Lithium batteries are very powerful but also a little finicky.

Anthony