Charging service vehicles and methods using modular batteries are disclosed. The service vehicles are vehicles having electric vehicle (EV) charging equipment, and removably mounted battery modules or battery module connection points. The battery modules are connected to the EV charging equipment as a source of electrical energy. Some embodiments disclose integrating the EV charging equipment with the vehicle, recharging modules through a distribution grid connection, the manner of discharging the batteries, modes of connecting and disconnecting the modules, the size and weight of the modules, quick-disconnectability of modules, control and monitoring of the modules and charging equipment, and/or ways of connecting modules to the vehicle. These features are beneficial to efficiently keep service vehicles available for EV charging through exchanging battery modules or providing additional battery modules when necessary, and may keep operators safe through de-energization of connectors and other precautions inherent in these designs.