This section applies to batteries installed to meet the requirements of § 129.310(a) for secondary sources of power to vital loads.
(a) Large. A large battery-installation is one connected to a battery charger having an output of more than 2 kW, computed from the highest possible charging current and rated voltage of the battery installed.
(b) Small. A small battery-installation is one connected to a battery charger having an output of 2 kW or less, computed from the highest possible charging current and rated voltage of the battery installed.