The new NMC4 battery in the Mercedes-Benz eCitaro: More capacity, longer service life

• Anniversary at Busworld: More than 3,000 eCitaro buses delivered
• More capacity, longer service life
• Proven large-scale production technology
• Higher power density, greater range
• Long service life despite fast charging
• Improved safety thanks to monitoring even when the vehicle is at rest
• Sustainable life-cycle management for NMC batteries

At Busworld Europe 2025 from 4 to 9 October, 2025 (3 October, press day), Daimler Buses will be presenting the Mercedes‑Benz eCitaro with the latest NMC4 battery generation. At the same time, the eCitaro is celebrating its anniversary: Since the start of series production in 2018, Daimler Buses has delivered over 3,000 eCitaro buses to customers.

The fourth generation of lithium‑nickel‑manganese-cobalt batteries – the successor to the current NMC3 technology – combines a high energy density, which enables greater ranges of e‑buses, with a very long service life. The new NMC4 batteries will be used in the Mercedes‑Benz eCitaro, eCitaro G, and eCitaro K low-floor city buses from 2026.

Proven large-scale production technology

The NMC4 battery is a proven technology from the battery system expert BMZ Poland, a BMZ Holding enterprise. This technology has already been produced in large scale for other applications since 2022 and was further developed by the Federal Ministry for Economic Cooperation and Development (BMZ) together with Daimler Buses for use in buses. In contrast to NMC3 batteries, the individual cells of the NMC4 battery are not cylindrical, but prism‑shaped. Twelve cells each form a module, 15 modules form a battery pack. The design of the NMC4 battery packs corresponds to that of the currently used NMC3 battery model. The new battery generation is therefore compatible with the current eCitaro in series production without any modifications to the vehicle. Even retrofitting existing eCitaro vehicles in the event that all battery packs need to be replaced is conceivable due to the given compatibility between the NMC generations.

Higher power density, greater range

A different composition of the cell chemistry in the NMC4 battery leads to an energy density that is almost 13 % higher than in the NMC3 battery and thus to a higher storage capacity with the same installation space. While a fully charged NMC3 battery pack contains 98 kWh of energy, the NMC4 battery has 111 kWh of energy. In addition, a higher share of the stored energy can actually be used for operation. Consequently, the possible range without recharging also increases considerably.

Long service life despite fast charging

Another important benefit for customers is the longer service life of the NMC4 battery and the resulting longer mileage of the eCitaro. Fewer battery replacements and less need for recycling contribute to sustainability and to reducing the total cost of ownership (TCO) of the eCitaro.

The longer service life of the battery is not only achieved with gentle, slow charging with a maximum charging capacity of 150 kW. The cell chemistry of the new battery demonstrates its advantages, especially during regular quick charging processes with up to 300 kW charging capacity, and can also score points with an extended service life in these applications. Daimler Buses is taking this opportunity to guarantee a service life of ten years for the new NMC4 batteries and optionally offer an extended customer-specific warranty with a duration of up to 15 years.

Improved safety thanks to monitoring even when the vehicle is at rest

The new battery generation can also score points in terms of safety. For example, battery monitoring, i.e. thermal monitoring and alarm activation in the event of overheating, does not only work as before with the NMC4 battery when the operating system is switched on, but also when at rest.

Omniplus as a reliable partner throughout the entire life cycle

Daimler Buses pursues a circular and sustainable approach to battery life cycle management and offers suitable solutions for the respective customer needs via the Omniplus service brand. The modular concept allows the batteries to be repaired and overhauled during their first service life. Subsequent use of the batteries outside their initial purpose in the vehicle extends their service life by a second service life in an energy storage system. The high‑voltage batteries are recycled at the end of their total service life with the objective of recovering raw materials.

Long range, individual battery installation, enormous increase in capacity

As usual, different versions of the battery equipment are possible for the eCitaro equipped with NMC4 batteries from 2026, both for the solo bus and the short eCitaro K as well as for the eCitaro G articulated bus. The battery packs of the new NMC4 battery generation have the same dimensions as the NMC3 packs. As before, the eCitaro solo bus and the short eCitaro K are therefore available with at least four and a maximum of six battery packs, which now have a higher capacity of up to 666 kWh together. The high‑voltage batteries are divided into three or four packs on the roof and two packs in what used to be the engine compartment. An exception is the version with four batteries. Here there are three on the roof and only one in the major assembly compartment.

The eCitaro G articulated bus boasts a minimum of four and a maximum of seven battery packs with a combined capacity of up to 777 kWh. Depending on the configuration, up to five packs are accommodated here on the front section as well as one on the rear section and in the previous engine compartment.

The maximum equipment guarantees a reliable range of up to 600 kilometers for the eCitaro solo bus and eCitaro K and up to 450 kilometers for the eCitaro G^[2]. This means that the buses cover the majority of the requirements of the daily driving performance of city buses.

Priority: Depot vehicle socket charging, optional opportunity charging

Thanks to its high energy capacity, the eCitaro with new generation batteries is also ideally suited for long routes and subsequent vehicle socket charging at the depot. In this process, charging capacities of up to 150 kW are possible. The familiar positions are available on the left and right above the front axle and at the rear. An additional plug position is also available in the area of the vehicle front. A maximum of two positions are possible per vehicle. Two eCitaro buses can also be charged sequentially, i.e. one after the other, at a charger with two charging points. This avoids charging peaks, saves infrastructure costs and still offers the operator the necessary operational flexibility.

For even longer routes, intermediate charging via pantograph or charging rails is also possible, also referred to as opportunity charging in the technical jargon. In combination with charging rails on the roof of the bus, even the maximum configuration with batteries is attainable. In this case, the charging capacity increases to up to 300 kW. In addition, the charging rails can be optionally equipped with an RFID tag to ensure unique vehicle identification during the charging process at the depot.

Innovative thermal management drastically reduces energy consumption

The battery capacity alone does not say enough about the performance and range of a fully electrically powered city bus – the true benchmark is energy consumption. In a city bus, it is very strongly influenced by the climatic conditions and thus by the cooling and, above all, the heating of the vehicle interior. Daimler Buses therefore places great emphasis on thermal management. For example, the high-voltage batteries are tempered to the ideal temperature. This leads to maximum charging capacity, performance, and service life. The passenger compartment is heated in an energy-saving manner by a heat pump and, if necessary – in the event of significant temperature changes – supported by the braking resistor connected to the water circuit.

For maximum efficiency, the eCitaro is equipped from the outset with a state‑of‑the‑art air conditioning system with sophisticated thermal management, which is operated with the refrigerant R744. For use in moderate temperatures, the EvoThermatic Basic air conditioning system is also available as an option for the eCitaro, with the EvoThermatic High Comfort air conditioning system available as an option for use in hot countries. All air conditioning systems available for the eCitaro have a highly efficient heat pump.

Another plus: The vehicle interior can be preconditioned to the desired temperature while the batteries are being charged at the depot. This means that the energy for the required climate control is not drawn from the battery at the start of the journey and the range is increased. Overconditioning is even possible: In winter, the city bus then starts with a higher temperature in the passenger compartment from the depot in order to counteract the cooling from the outside, which further reduces consumption during operation. Similarly, it is already precooled somewhat stronger in the summer.

Proven portal axle

The drive of the eCitaro is based on the proven and optimized ZF AxTrax 2 LF portal axle with electric motors on the wheel hubs. The peak output of the motors is 440 kW, the continuous output 360 kW and the continuous torque 407 Nm. The latter is fully available from the start thanks to the system and ensures appropriate dynamics even with full occupancy.

Cockpit and operating concept correspond to the conventionally powered Citaro

The layout of the eCitaro’s passenger area corresponds to that of the usual Citaro models. The almost identical operation compared with the Citaro with a combustion engine therefore allows the usual quick change of driver. However, the instrumentation meets the requirements of the electric drive: A power availability display replaces the tachometer. It shows the current power demand or recuperation. The driver also receives information about the state of charge of the batteries. From the central display, they can access the range, power availability, and a charging indicator. The eCitaro also helps its driver in energy‑saving driving with an acceleration control system: When moving off from a bus stop or traffic lights, whether empty or under full load, the acceleration is limited to a comfortable level. This leads to a gentle, passenger‑friendly driving style and at the same time reduces energy consumption.

The unrivaled safety of the eCitaro

For Mercedes‑Benz buses, safety does not consist of individual measures, but is based on a comprehensive, integral safety concept. With the eCitaro articulated bus, this begins with the driver‑fitness safety. Its cockpit corresponds almost completely to the usual Citaro and does not require any getting used to. The seat, visibility, ergonomics and climate control are exemplary. The comfortable and secure chassis with electrohydraulic, intelligent eco steering and roll‑pitch control has earned a great deal of recognition.

A safety focus includes high-voltage technology with impact-proof mounted battery modules and well protected charging cables. The batteries are tested and certified in accordance with hazardous goods regulations. With tests of the cell, cell block, battery pack and the battery groups in the vehicle, the battery systems are extremely safe.

The active safety of the eCitaro is unrivaled. For example, all models are equipped as standard with a wide range of assistance systems with functions that, in some cases, go far beyond what is required by the General Safety Regulation (GSR) of the European Union.

For example, the radar-based Sideguard Assist 2 of the second generation is standard equipment in the eCitaro. Sideguard Assist 2 reacts and warns even more precisely in the event of a risk of collision with pedestrians and cyclists. It is now also used for the left side. In addition, Sideguard Assist 2 takes over the function of a lane change assistant at speeds above approx. 40 km/h. Up to the maximum permissible speed, it informs the driver of objects on both sides of the vehicle. In critical situations during a lane change, the system generates a visual and haptic warning. Sideguard Assist 2 thus supports lane changes, for example when overtaking a cyclist or when changing lanes on multi-lane roads.

Frontguard Assist detects and warns of obstacles or people directly in front of the vehicle. Together with the now standard reversing camera or especially the optional 360° camera system (270° camera system for articulated buses), the driver is provided with a comprehensive information and warning system all around their eCitaro bus.

The intelligent Traffic Sign Assist speed limiter warns when the permissible speed is exceeded. The standard equipment of the eCitaro also includes the tire pressure monitoring system (TPM) and Attention Assist (AtAs) as well as an interface for the use of alcohol testers for the driver cockpit.

Omniplus Charge: Total e-mobility from a single source

From autumn, Daimler Buses Solutions GmbH will be offering its services under the new Omniplus Charge brand and thus under the strong common Omniplus brand umbrella. This combines classic services with Omniplus On to provide a comprehensive range of digital services. Daimler Buses Solutions advises transport companies and actively accompanies them on their journey to e‑mobility. The enterprise specializes in consulting, designing, and building e‑mobility and H₂ infrastructure. In cooperation with experts from Daimler Buses Solutions GmbH and other partners, Daimler Buses can supply the entire e‑mobility ecosystem from a single source if requested: From the feasibility analysis, to the custom‑configured electric bus, to the complete e‑mobility infrastructure for the depot, including construction measures, electrical installations, chargers (including maintenance and service), battery storage facilities, charging management systems, and other digital services.

New in the portfolio is the Charging‑as‑a‑Service offering, whereby Daimler Buses takes over the operation of the charging infrastructure completely and the customer can conveniently charge at their own depot with monthly billing.

Omniplus: New digital services for electric buses

Another plus for all eCitaro buses is the comprehensive service offered by the Omniplus service brand. It not only has the largest bus-specific service network in Europe, but also the number of specialized eBus service centers with employees qualified for high-voltage work and the corresponding technical equipment already comprises more than 120 eBus service centers in Europe and is constantly growing.

In addition, digital services are becoming increasingly important, as they offer the opportunity to make bus operations even more efficient, economical, and safe. With its Omniplus On portal, Daimler Buses offers a wide range of digital services: From online remote diagnostics, Uptime and Uptime pro, and location services, consumption and driving analyses, to the “Remote Control Functions” charging and preconditioning control for electric buses. With the current Digital Services Package, all buses delivered by Daimler Buses from this year onwards will temporarily receive a number of digital services as a free option. For electric buses, these can be used free of charge for six years.

Another new feature is the Omniplus On monitor location services plus. This allows speed-based geofencing to be set up, which uses the vehicle’s position data for activation of the speed limiter. The new service increases safety and takes the strain off drivers.