Lessons from more than a decade working on electric motorcycles and compact vehicle platforms.
By Ino González · Guilera · guilera.com
Reading time: 6–7 minutes
Electrifying a compact vehicle looks straightforward on paper. Motor. Battery. Inverter. That is usually where the conversation starts — and, in our experience, where the underestimation begins.
After more than a decade designing and supplying power electronics for electric motorcycles and compact off-highway platforms, we have seen the same patterns repeat across projects: the visible part of the system gets all the attention at the start, while the invisible part — integration, architecture, diagnostics, CAN communication — is where projects actually succeed or fail.
This article brings together ten realities we have observed working alongside OEMs and system integrators. Each one is something that experience teaches, usually the hard way. We are sharing them here because understanding them early can change the outcome of a project.
| 1 | Electrification is not just a drivetrain — it is a complete electrical system |
The motor, battery and inverter represent perhaps 30% of the engineering effort in a real vehicle project. The other 70% sits below the surface: electrical architecture, wiring harness design, power distribution, DC/DC conversion, diagnostics and control systems.
| The drivetrain is the visible part. The system is what makes or breaks the vehicle. |
Every project that starts with ‘we just need to integrate a motor and a battery’ eventually discovers this. The difference is whether it is discovered in the planning phase or during prototype debugging.
| 2 | Electrical architecture decisions define the entire project |
Architecture errors propagate everywhere. A connector placed in the wrong location, a voltage platform chosen for the wrong reasons, a power distribution strategy defined too late — these decisions shape cost, weight, reliability and serviceability for the entire vehicle life.
The most consequential early decisions include:
- Overall electrical architecture of the vehicle
- Voltage platform (48V / 72V / 96V)
- Power distribution strategy
- Connector philosophy and environmental protection levels
| In one off-road motorcycle project we worked on, the motor controller was positioned below the pedal area — exposed to water, debris and impacts. Protecting it required mechanical redesign, additional wiring complexity and added weight in a critical zone. Early architecture decisions could have avoided that entirely. |
Small component choices matter. But architecture mistakes are the ones that become expensive.
| 3 | Voltage architecture determines system behaviour — not just power output |
Typical ranges for compact electric vehicles follow a clear pattern:
- 48V → up to ~5 kW continuous
- 72V → up to ~10 kW continuous
- 96V → up to ~25 kW continuous
But voltage selection is not simply a power question. It directly impacts current levels, cable cross-sections, connector durability, thermal management requirements and DC/DC architecture. At 10 kW and 48V, you are working with roughly 200 A — a figure that changes the entire conversation about cables, connectors and thermal behaviour.
| Voltage selection should be an engineering decision, not a marketing one. |
We have seen projects where the voltage platform was chosen to match a supplier’s off-the-shelf battery pack, with the downstream consequences handled later. Later is always more expensive.
| 4 | The number of suppliers matters more than people expect |
Each additional supplier introduces new variables into the system. Different documentation standards, different firmware update cycles, different levels of integration support. In complex electrification projects, this quickly multiplies integration risk.
Reducing the number of suppliers tends to improve:
- System coherence — components designed to work together
- Project efficiency — fewer interfaces to manage
- Troubleshooting speed — clear ownership when something goes wrong
- Cost control — fewer commercial relationships to manage
Concentrating responsibilities in a smaller number of experienced partners simplifies integration and reduces friction during the phases of development where friction is most expensive.
| 5 | Supply agreements matter more than engineers expect |
Technical success depends on more than engineering. We have seen well-designed systems run into serious difficulties because the commercial structure supporting them was poorly defined.
Poorly written supply agreements can generate supply interruptions, delivery delays, unexpected price increases and integration conflicts as a project scales. These are not abstract risks — they are recurring patterns in electrification projects that grow beyond the prototype stage.
| Well-structured agreements, written with experience of how these projects actually evolve, are not a legal formality. They are a project risk mitigation tool. |
| 6 | Connector systems and removable batteries deserve far more attention than they receive |
Battery connector systems and removable battery interfaces look straightforward in specifications. They rarely stay straightforward in the field.
The failure modes are consistent: mechanical wear, terminal deformation, overheating due to contact degradation, and environmental exposure. In high-cycle applications — where a battery is removed and re-inserted many times per day — connector specifications that look generous on paper can prove inadequate within months.
If a removable battery concept is required, the connector system should be over-dimensioned relative to the nominal specification. This is one area where the cost of doing it correctly at the start is always lower than the cost of redesigning it later.
| In several early electric vehicle projects we worked on, removable battery connectors degraded far earlier than expected. Even connectors from recognised brands overheated after repeated insertion cycles when the concept had not been sufficiently over-dimensioned for real-world use frequency. The specification had looked adequate. The field disagreed. |
| 7 | Testing effort is consistently underestimated |
Running a prototype is not validation. A prototype that moves and performs correctly in controlled conditions tells you that the system can work. It does not tell you that the system will work reliably across a product life in real operating environments.
A serious development programme requires:
- A structured test plan, defined before testing begins
- A dedicated testing engineer with vehicle system experience
- Environmental validation — temperature, humidity, vibration, ingress
- Durability validation — cycle testing over representative product life
When internal validation resources are limited, selecting component suppliers with strong validation capabilities, or engaging experienced testing facilities early, becomes essential to programme integrity.
| 8 | EMC is frequently discovered too late |
Electromagnetic compatibility is one of the most common sources of late-stage programme delays in vehicle electrification. It tends to be treated as a certification step rather than an integration challenge — which means it is often the last thing tested, and the most disruptive when problems appear.
Integrating power electronics into compact vehicles requires specific experience. When components are not designed or integrated with EMC in mind, the consequences can include:
- Repeated test failures that reset certification timelines
- Long debugging sessions with unclear root cause attribution
- Programme delays that affect launch dates and commercial commitments
| Even when the EMC problem originates in a specific component, the entire vehicle programme absorbs the cost. |
We have seen projects where a motor controller from a third-party supplier introduced conducted emissions that caused repeated certification failures. The component met its own datasheet. But once integrated into the vehicle harness, with the specific cable routing and grounding topology of that platform, the system failed. Debugging took weeks and required rerouting sections of the wiring harness that had already been finalised.
EMC planning belongs at the architecture stage, not the certification stage.
| 9 | Small component details have a disproportionate effect on system durability |
Surface finishing, sealing, environmental protection ratings, connector ingress protection levels — these details appear secondary during the intensity of early development. In the field, they determine whether a vehicle lasts two years or ten.
A well-sealed DC/DC converter, for example, does not just protect against moisture ingress. It protects the aesthetics of the installation, maintains thermal performance over time, and reduces the likelihood of premature replacement. Durability and industrial design meet at the component level.
In off-highway and demanding outdoor environments, the components that fail first are almost always the ones whose environmental protection was treated as optional.
| 10 | Durability is part of sustainability |
Electrification is most often framed around environmental impact — lower emissions, reduced fuel consumption, cleaner operation. These are real and important benefits.
In compact vehicles used in demanding environments — agriculture, construction, last-mile logistics, off-highway — sustainability is not only about energy sources. It is equally about durability and service life. A vehicle that lasts ten years and requires minimal replacement parts delivers a fundamentally different environmental footprint than one that needs major interventions within three.
But real sustainability also depends on how long a vehicle lasts, how reliably it operates, and how easily it can be serviced. A vehicle that requires frequent component replacement, or that has a shortened useful life due to inadequate electrical architecture, does not deliver the environmental promise of electrification.
| Designing robust architectures and durable components is both an engineering responsibility and an ESG one. |
The vehicles that contribute most to sustainability over their product life are the ones built to last.
From posts to practice
Over the past weeks, we have shared this series of realities as individual posts on LinkedIn — using the language of engineering teams who live these challenges daily. The response confirmed something we already believed: these patterns are widely recognised, because they are widely experienced.
The goal of this article is not to catalogue problems, but to make the invisible visible early enough to act on it. Architecture decisions made in the first weeks of a project shape everything that follows. Supplier choices made without considering integration complexity tend to create the CAN debugging nights and connector failures that appear later.
Experience does not eliminate these challenges. But it makes them visible earlier — and that changes what you can do about them.
| Working on an electrification project? At Guilera, we have been designing and supplying power electronics — motor controllers, DC/DC converters, and complete electrical architectures — for compact electric vehicles for over a decade. We work alongside OEMs and system integrators from early architecture decisions through to series production. If you are facing any of the challenges described in this article, we would be glad to discuss them. Contact us at guilera@guilera.com |
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