ContentServer. asp. pdf - GM Volt Forum Bolt EV High Voltage (HV) battery cooling heating — The HV battery on the Bolt EV has an external 2 5 kW heater, external coolant chiller (a mini-evaporator connected to the A C system) and internal cooling manifolds, cooling plates and coolant hoses 2 HV Reserve Energy Storage System (RESS) battery cooling heating loop