Retrofitting


e-troFit is the only OEM-level series conversion provider.

With our multiple award-winning retrofit kit, we turn your existing commercial vehicle into a state-of-the-art electric vehicle that is in no way less powerful than new vehicles. This is how you get into electric mobility and continue to use your existing buses or trucks in a cost-effective and environmentally friendly way!

Quality standards satisfied by our e-troFit® kit:


  • TÜV certification. The kit undergoes TÜV testing, which guarantees the customer that this complies with European standards
  • Compliance with relevant norms and standards for all components (e.g. ISO 6722-1, ECE R100, ECE R10, VDV230)
  • Regular quality audits internally and with all component suppliers
  • ISO 26262-compliant development: functional safety & testing of system and components
  • Regular maintenance during normal operation
  • Selected suppliers with high quality level and more than ten years of experience in the field of commercial vehicles and refurbishment works
  • Working according to ISO 9001 Quality Management and ISO 45001 Occupational Health & Safety
  • Compliance with ISO 14001 Environmental Management and ISO 50001 Energy Management

e-troFit Bus

With the e-troFit® kit, we retrofit existing diesel buses to electric drive. e-troFit GmbH provides the conversion service including all necessary components and the complete regular approval for road traffic according to the previous type of use of the bus.

The e-troFit® concept bus includes the retrofit with the e-troFit® kit, consisting of the components Vehicle Control Unit, powertrain, battery modules, auxiliary units, heating/air conditioning, telematics unit and driver additional display as well as TÜV certificate and TÜV vehicle approval according to its previous type of use.

e-troFit Truck

With the e-troFit® Kit Truck, we retrofit existing trucks to electric drive. The e-troFit GmbH provides the conversion service including all necessary components and the complete regular approval for road traffic according to the previous type of use of the truck.

The e-troFit® concept truck includes the retrofit with the e-troFit® kit concept truck Mercedes Benz Actros, consisting of the components central drive, battery modules, auxiliary units, air conditioning compressor and driver additional display as well as TÜV certificate and TÜV vehicle approval according to its previous type of use.

Project flow

Phase 1: Analysis

Your e-troFit bus adapts to your individual requirements: We analyze your driving operation with regards to route lengths, uphill gradients, traffic conditions and other influencing factors. In addition, we carry out a detailed technical assessment of the vehicles to be converted.

Phase 2: Concept

Based on the analysis data, we design the battery, powertrain and charging concept specifically to ensure that the vehicle will be able to meet all of your everyday requirements. The battery, as the most expensive component, is dimensioned in such a way that the necessary ranges are achieved without installing unnecessary battery capacity. The charging concepts allow both night charging and opportunity charging.

Phase 3: Retrofit

One of our certified partner workshops will modify your vehicle, put it into operation and carry out technical approvals. You will receive an operational and fully registered vehicle. The conversion usually takes about 4 weeks. If required, further modernisation work can be carried out on the vehicle as part of the conversion.

Phase 4: Start of operation and on-going maintenance

We accompany you during the start-up and will be your partner for questions. In addition, we organize the training of your workshop staff and the planning of the necessary charging infrastructure. Service and maintenance can take place in the worldwide workshop network of our service partner ZF, as well as with other certified partners.

FAQ on Retrofit

How long does the conversion take and how is it done?

The e-troFit conversion takes place in two phases:

1. Analysis phase First, the vehicles to be retrofitted undergo a technical check to determine whether they have special technical features. In addition, the conditions under which the vehicle will be used later are analysed (route lengths, route profiles, circulation times, loading points, etc.).

Based on this, the exact design in terms of range, battery capacity and some other characteristics is determined. Depending on the effort involved, this analysis phase takes approx. 3-6 months.

2. Retrofitting The vehicle is brought to one of the partner workshops for the actual conversion. The conversion takes approx. 4 weeks (assuming availability of all components).

What is the operating range of an e-troFit bus?

Battery capacity and range of each bus are individually adapted to the operator's requirements. For public transport operation, ranges of 200-250km are usually sufficient and feasible.

Which components will be replaced during the conversion?

Powertrain and battery Diesel engine, gearbox and drive axle are removed and an electric drive axle is installed. For city buses, we use an electric low-floor portal axle by ZF (AVE130). This axle relies on the concept of the integrated close-to-the-wheel drive with two liquid-cooled asynchronous motors.The battery modules are installed in the former engine compartment (additional capacity can be installed on the roof, if necessary).

Ancillary units All auxiliary components previously driven by the combustion engine (such as air conditioning, air compressor, pumps etc.) are removed and replaced by electrically powered components. An efficient control system, which takes over the interaction of these components, guarantees the most energy-efficient operation possible.

Driver’s position An additional display is installed at the driver's seat, which provides the driver with information on the vehicle status, charge status and any errors.

Which power train technology is used?

In city buses, we use the AxTrax Ave electric portal axle from ZF: Each wheel is powered by a compact, high-speed, liquid-cooled asynchronous motor, which keeps the axle weight low. The maximum motor output is 250 kilowatts and a maximum torque of 22,000 Newton meters.

No separate engine or cardan shaft is required, reducing space requirements and vehicle weight. The resulting space can be used to install a more powerful battery or optimize the vehicle interior to carry more passengers. The AxTrax Ave does not require any special wheel components. This means that the tire-rim combinations used in conventional buses can also be used, as well as standard disc brakes. The brakes are installed in the same maintenance-friendly position as with the standard axles.

Which battery technology is used?

e-troFit has developed a modular battery module based on lithium-ion batteries (NMC). The individual module has a capacity of 60kWh, several of these modules can be connected in parallel to achieve the desired capacity.

Does the retrofitted vehicle have a road registration?

We take over the road approval for you - the retrofitted vehicle will be delivered ready for operation and with road approval.

Where can I get retrofitting and service for the e-troFit bus?

e-troFit has signed a preferred partnership with ZF: ZF not only supplies the powertrain components for e-troFit, but also offers the workshop network for e-troFit conversions.

By partnering with ZF, we can ensure sufficient workshop capacity and carry out retrofits in ZF's local workshops. Since retrofitting poses a major challenge in terms of technical know-how, the workshops are carefully inspected and selected accordingly. In addition, the worldwide service network of the ZF Group is available to ensure optimal and customer-oriented maintenance of the conversion kit.

Are there any government subsidies for the conversion?

In Germany, municipal bus operators are benefiting from the German government's "Clean Air 2017-2020" emergency programme: this funding programme provides 350 million euros for the electrification of urban transport. Retrofitting of existing buses is also eligible!

Subsidy programmes also exist in many other countries. We will be happy to advise you on the specific conditions at your location.