Frequently asked questions

We have compiled the most frequently asked questions and answers about e-troFit for you.

We put great emphasis on adapting your e-troFit vehicle exactly to your requirements. That's why we offer you detailed personal advice on your specific questions. Please contact us, we will be happy to assist you!


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.

Which charging concepts are available?

With e-troFit, both overnight depot loading and opportunity charging during ongoing operations (e.g. at the terminal stop) are possible.

Which method is appropriate and economical in the individual case depends on the specific route lengths and timetables of the operator. We check these requirements during the analysis phase and develop a coordinated loading concept.

If Opportunity Charging is selected, simple and fast loading can also be implemented using Pantograph.

Where can I get the necessary charging infrastructure?

During the analysis phase, we select the most suitable charging concept. We then advise and support our customers in the selection and installation of the appropriate charging infrastructure and, if necessary, also plan these projects.