The system can also be used with just one battery. In this case it doesn't matter which socket the battery is connected to.Related ArticlesWhat is the Bosch DualBattery technology?How does the Bosch DualBattery work while riding?How are the batteries charged with the Bosch DualBattery technology?Can I retrofit the Bosch PowerMore add-on battery?Where can I find the serial number of my Bosch battery?