From Rallye to Rall-E: How a Broken Mower Sparked an Electric Idea
From "Rallye" to "Rall-E"
How a Broken Lawnmower Became a Fully Electric Prototype – Powered by Neomium
When a broken lawnmower engine sparked an idea, Neomium’s engineers turned it into Rall-E – a ride-on mower electrified with the CÆSIUM® Cs-40 controller, modular magnetic battery packs, and a hint of movie-robot charm.
From Rallye to Rall-E – How a Broken Mower Sparked an Electric Idea
Every engineering company has its small side projects – the ones that start with a “what if” during a coffee break. For Neomium, that moment came when our old Rallye UM1136 ride-on lawnmower broke down on the way to the test field.
The internal combustion engine was done: a blown cylinder-head gasket, beyond easy repair. We could have ordered a new engine, repaired it, or have it repaired. But instead one of our engineers asked the question that defines our brand philosophy:
“Why not electrify it?”
And just like that, Project Rall-E was born.
A Proof-of-Concept with Personality
The name came naturally. “Rallye” turned into Rall-E – echoing not only the original machine but also the spirit of a beloved movie robot that turned scrap into hope.
Where that robot collected waste, our Rall-E mows lawns – demonstrating that Neomium’s technology can power anything from future aircraft systems to… a humble lawnmower.
Painted in rusty orange, fitted with two expressive robot eyes, and equipped with a digital dashboard showing speed, voltage, and power, Rall-E became both a functional prototype and a character – a small ambassador of what’s possible when engineering meets creativity.
Powertrain
Underneath Rall-E’s playful exterior lies a fully functional electric powertrain built from Neomium’s core technologies.
The CÆSIUM® Cs-40 Controller
At the heart of Rall-E beats our Cs-40 mid-voltage motor controller, capable of 40 kW peak power and operating in the 180-200 V range. Running on open-source VESC® firmware, the controller offers full transparency and configurability – the same philosophy that makes it a favorite among developers in e-mobility research.
Its modular communication setup (CAN, UART, analog interfaces) and high thermal efficiency made it the ideal choice for this small-scale demonstration.
Magnetic, Weld-Less Battery Modules
The power source? A set of Neomium’s proprietary modular batteries, based on our magnetic cell contacting. Instead of welds or solder joints, the cells are connected magnetically, allowing tool-less assembly, full recyclability, and straightforward second-life use.
Each module is individually monitored at single-cell level, ensuring safety and longevity even under rough test-field conditions. This technology is currently advancing toward CE certification – and Rall-E provided the perfect playground to test robustness, vibration resistance, and integration flexibility.
The Dacia Spring Motor
For the drive unit, a reused Dacia Spring electric motor was chosen – a compact, efficient traction motor that perfectly matches the Cs-40’s capabilities. By repurposing an existing EV motor, we demonstrated how second-life hardware can blend seamlessly with first-class control electronics to create a fully functional conversion.
The Build
From Workshop Sketch to Working Prototype
The build process unfolded over a few weekends and many cups of coffee. Our engineers and interns teamed up, combining mechanical retrofitting with electrical integration:
– Mechanical adaptation: removing the gasoline drivetrain, adapting the chassis, and integrating the motor mount
– Electrical integration: installing the Cs-40, wiring the battery clusters, and implementing safety cut-offs
– Control & display: connecting a simple HMI that visualizes speed, voltage, power, and energy use (Wh)
After the first successful test run, Rall-E quietly cruised through the grass – zero emissions, low noise, and 100 % smiles 🙂
Just for Fun?
A Showcase of Real Capabilities
“It’s a fun project – but also a serious demonstration of our system-integration capabilities,” says Tobias Salbaum, Co-Founder of Neomium.
“We design and build modular, circular, and open systems – and we can electrify almost anything.”
The project highlighted Neomium’s ability to:
– Rapidly prototype mid-voltage powertrains using in-house controllers and battery systems
– Combine mechanical, electrical, and software expertise in a compact integration cycle
– Repurpose existing hardware for sustainable innovation
– Turn technical proof-points into relatable, human stories
Why Fun Projects Matter
Projects like Rall-E bridge the gap between innovation and communication. They demonstrate what’s technically feasible – while reminding everyone that electrification isn’t just about specs and standards, but about creativity, re-use, and joy in engineering.
Sometimes the best way to show what’s possible is to build something nobody asked for – and make it work flawlessly.
Rall-E may mow the grass, but its real job is to inspire.
What’s Next?
Neomium is currently advancing several large-scale electrification programs – including propulsion systems, battery platforms, and integrated safety electronics for light-electric vehicles and aerial-mobility applications.
Rall-E served as a playful demonstration of these technologies in action – and as a reminder that serious innovation can have a sense of humor.
Want to Electrify Your own Project?
If you’re curious about our controller platforms, battery technology, or integration capabilities, feel free to get in touch. Neomium supports partners and startups in developing modular electrification solutions – from early prototype to production readiness.
Reach out: info@neomium.eu or +49 8063 2569772
Disclaimer
All references to cinematic characters or themes are purely inspirational. “Rall-E” is an independent prototype created by Neomium GmbH and is not affiliated with or endorsed by any film or media franchise.
© 2025 Neomium GmbH – All rights reserved. CÆSIUM® is a trademark of Neomium GmbH. VESC® is a registered trademark of Benjamin Vedel and vedder.se, used under acknowledgment.
Neomium GmbH is a technology-driven startup founded in October 2022, dedicated to propelling electrification across mobility and aviation. We develop and deliver high-performance electronic components — like motor controllers and power systems — designed for the demands of next-generation electric vehicles. Alongside our product line, we’re also advancing an innovative cargo drone concept aimed at reshaping aerial logistics.
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