Lithium ion polymer batteries need to be charged very carefully.The basic concept is to first charge each cell at a constant current of 4.2V.The charger must then switch to constant voltage mode, and as the charging current decreases, the charger must keep the battery cell at 4.2V until the current drops to a certain proportion of the initial charging current and stops charging.Some manufacturers set specifications at 2 to 3 percent of the initial current, although other values are acceptable, but the difference in battery capacity is small.

    Balanced charging means that the charger monitors each cell and charges each cell to the same voltage.

    Trickle charging is not recommended for lithium batteries.Most manufacturers set minimum and maximum voltages for cells at 4.23V and 3.0V, and any cell beyond this range may affect the overall battery capability.

    Most good lithium-ion chargers also use a charging timer that automatically stops charging when the time is up (usually 90 minutes) as a safety feature.

    lithium ion polymer batteries with a charge rate of up to 15C(15 times the battery's charging current, or about four minutes of charging) were made possible by a new type of lithium-ion nanowires in early 2013.However, this is still the exception, and the generally recommended 1C charge rate is still the standard for remote model players.No matter how much charging current the battery can withstand, it is important that a lower charging rate can extend the service life of the model aircraft battery.

    Similarly, continuous discharges of up to 70C (70 times the battery capacity) and instantaneous discharges of 140C were also achieved in mid-2013 (see "Remote Control Model" section above).Both of these discharge "C-number" standards are expected to increase as lithium-ion nanobattery technology matures.Users, too, will continue to push the limits of these high-performance lithium-ion batteries.