Mercedes-Benz has delivered three all-electric eCitaro electric city buses to German local public transport company Rhein-Neckar-Verkehr GmbH (rnv).
The first purely electric eCitaro bus service in Heidelberg goes from the main train station via the Seegarten to the Karlsplatz and then later to the Altstadt commuter rail station. Bus route 20 travels through Heidelberg’s city centre every 20 minutes, whereby it is expected that in the future two vehicles will cover the four kilometre long route with 12 stops.
One of Mannheim’s electric bus routes leaves from Käfertal train station and travels via Wasserwerkstraße to the Franklin district, a new district where members of the US armed forces used to live. The other route begins at the Platz der Freundschaft and ends at the new Taylor industrial estate, which also once belonged to the US armed forces. One eCitaro will be in operation on each route.
In Heidelberg, the vehicles will be on the road between 9.00 a.m. and 10.00 p.m. and in Mannheim between 6.00 a.m. and midnight. This corresponds to a daily mileage of about 200 kilometres or more per vehicle. Accordingly lithium-ion batteries with a total capacity of 243 kWh will provide the electric power. The battery design is modular, comprising 10 modules each with an output of 25 kWh. In addition to the six battery modules on the vehicle’s roof, four battery modules in the rear take the position of today’s drive system combination of combustion engine and transmission.
Charging technology in the depot
With its charging technology the eCitaro adapts to the conditions provided by rnv. The target is a mileage of 200 km or more for each vehicle which can be achieved with fast charging in the form of top-up charging during breaks in operation. During these breaks another eCitaro will be in operation in Heidelberg and Mannheim, otherwise it would not be possible to meet requirements. The buses are charged using a combi-2 plug, located on the right in the direction of travel above the front wheel housing. The new ISO 15118 standard offers extended functions which enable for example automatic authentication of vehicles without a separate charging card. With the help of extended data transmission, Mercedes‑Benz developed a function with which automatic control of preconditioning in buses is realised via the charging connector. Thus, there is no need for additional cables or lines for compressed air, low voltage or communication. The newly developed charging device has an output of up to 150 kW and is to be delivered to rnv together with the eCitaro. This guarantees the simplest, fastest and most favourably priced variant of the power supply.
Mercedes-Benz will continue to support the rnv after the buses and charging stations have been purchased: Together with energy management specialists, “The Mobility House” from Munich, Mercedes-Benz is developing and implementing a customised charging management system. Charging is optimised in a way that the connection power of the charging devices and the requirements of the vehicle battery are taken into account.
