Riese & Müller is one of the first E-Bike manufacturers to implement Bosch Dual Battery technology. which makes their bikes unbeatable when it comes to range. Note that 2 batteries will add considerably more weight to the bike, usually around 7lbs, and can't be retrofitted, so you gotta choose it up front.
How does the Dual Battery technology work?
While riding, the batteries alternate. The system automatically tracks the charge states of both batteries and switches between them when it detects a charge difference of five percent. This ensures that both batteries are discharged and used in an equal manner, which significantly prolongs the service life of the batteries. If necessary, riders also have the option to use just one battery. In this case, it doesn't matter which unit the battery is attached to. The two batteries can be charged directly on the bike or detached and charged on an external charger – which is very convenient when no socket is nearby. Both batteries have the same key, which saves time searching for the right one. The same charger can be used to top up the batteries whether mounted or removed, but it is only possible to charge both of them simultaneously directly on the bike. The charging time for both 500 Wh batteries, starting from a completely discharged state, is about 9 hours, or 4.5 hours for just one of them.