$t_{\text{NC}}=\frac{E_{\text{NC}}}{P_{\text{CN}}}$

Note 1 to entry: The second (s) is the base unit of the nominal charging duration; other units can also be chosen for convenience (e.g. h).

Note 2 to entry: With reference to an EES system based on secondary batteries and to the definition of "charge rate", the nominal charging duration t_NC is the minimum duration for which the secondary batteries' rated capacity should be declared (this rated capacity should be also compatible with P_CN).