Leaving empty batteries for a long time in your appliance without charging causes critical damage to the electrode of the cell (over-discharging) and shortens battery service life, so try to avoid this.
Charge your batteries frequently. Ideally, batteries should be recharged when 70% of their capacity has been consumed. This will make sure there is no chance of over-discharging the batteries, which is one of the main causes of damage to the cells.
Do not use batteries in high temperatures as this increases internal pressure within the cell, which induces leakage and a shorter service life.
Group your batteries. When batteries are grouped together for one appliance, e.g. 4 x AA for a toy, means the cells will discharge simultaneously. If one battery is taken out to be used in another appliance, e.g. to operate an LED light, and then put back in the toy, this results in 1 out of 4 batteries having a different power level than the others. This will cause the cell to degrade and over-discharge more rapidly.
In order to maximise the performance of rechargeable batteries, it is vital to use cells of equal condition. Use batteries of the same specifications such as:
Using rechargeable batteries of different conditions will increase the performance gap between the cells which will lead to unnecessary degeneration of the batteries and their service life. It could be useful to mark your batteries with a permanent marker in order to maintain the differentiation.
Make sure the battery cell’s terminal and charger are cleaned frequently. Repeatedly using rechargeable batteries leads to (invisible) contamination (such as grease or dust) on the batteries and the charger, which will adversely affect your Panasonic products in terms of performance. As a result, such dirt could obstruct the charging of the cells along with shortening the discharge time of the batteries. For these reasons, Panasonic urges its customers to clean their batteries and chargers frequently using a cleaning cloth.