Many Nikon cameras use an EN-EL Lithium-ion battery as a power source. Nikon Lithium-ion (Li-ion) batteries have negligible memory effect and therefore do not require refreshing as required by Ni-Mh batteries used by other digital cameras, to maintain optimal performance. The battery itself is not covered under a Nikon warranty, while the battery charger is covered by the warranty.
If the camera is to be stored for an extended period of time the battery should be removed from the camera. Nikon recommends that batteries should be charged and used at least once a year. There is no need to discharge the battery before recharging. If the battery is left in the camera for extended periods, a minute electric current continues to flow, which may drain the battery excessively, resulting in over discharge, and a deterioration of the battery.
Care should be taken with the battery when it is not in the camera. It should not be stored where keys, coins or other metal could touch the contacts. Ideally the supplied plastic cover should be used to protect the contacts.