A burner system includes a fuel nozzle, an electrode configured to apply electrical energy to a combustion reaction supported by the fuel nozzle, a high-voltage converter configured to receive electrical energy from a low-voltage power supply and to provide high-voltage power to the electrode, a battery charger, and a switch module coupled to the battery charger, the converter, and first and second batteries. The switch module is selectively switchable between first and second conditions. In the first condition, the first battery is coupled to the battery charger and decoupled from the high-voltage converter, while the second battery is coupled to the high-voltage converter and decoupled from the battery charger. In the second condition, the first battery is coupled to the high-voltage converter and decoupled from the battery charger, while the second battery is coupled to the battery charger and decoupled from the converter.