You don't need to worry about anything when riding. The system automatically ensures an equal discharge of both batteries. Related ArticlesDoes the RX Chip record when I transport my bike on a bike carrier on a car?How does the Bosch DualBattery work while riding?Do I have to swap the Bosch DualBattery batteries from time to time?Can I ride twice as far with Bosch DualBattery?Smart lock from I Lock It