6 Myths about solar for trucks and trailers — What fleet managers need to know

Solar technology in commercial transportation is growing rapidly and making a real impact, yet myths and misunderstandings about its reliability and effectiveness still persist. In this article, we’ll debunk the 6 most common myths about solar technology for trucks and trailers, using real data, case studies, and practical examples to explain how solar significantly improve your fuel efficiency, reduce CO₂ emissions, cut idling costs, and enhance your fleet's performance.

Myth 1: On-board solar technologies don’t provide energy enough to power trucks  

Fact: Solar systems do not generate enough energy to fully power a vehicle’s propulsion system. Instead, they are primarily used to supply power to auxiliary electrical systems and reduce the load on the alternator, thereby saving fuel and lowering emissions. The annual electric energy demand ranges from 1.000 kWh to over 4.000 kWh, depending on the vehicle and the types of electrical devices in use.

Today’s commercial vehicles use a range of electrical components, including: tail lift, internal lift, movable floor, pallet truck, ventilation, battery packs, truck electronics, truck cabin, HVAC… These systems constantly draw power from the alternator, sometimes even when the vehicle is stationary.

On-board solar technology harnesses sunlight to power these auxiliary systems, reducing the need to idle the engine or put extra strain on the alternator.  

The result: Lower fuel consumption, less battery wear, fewer breakdowns, reduced maintenance costs, and more uptime for your fleet. 

For electric trucks, solar power can significantly reduce parasitic loads on the vehicle’s electrical system, thereby increasing its driving range.

Myth 2: Solar technologies are too expensive for trucking companies to justify the investment.

Fact: The cost savings from reduced fuel consumption, longer component life, fewer repairs, and less downtime typically result in an ROI within 3 to 4 years depending on vehicle type, usage patterns, and the specific solar system installed. 

Key cost savings realized by onboard solar solutions are:  

• • Reduced engine load and unnecessary idling

The alternator generates electricity by putting mechanical load on the engine. The more the alternator works, the more fuel is consumed. By using onboard solar technology to power auxiliary systems, the engine experiences decreased loads, idles less, and consumes significantly less diesel fuel. 

Typical savings: 1.500–3.000 liters/year per vehicle 

Example: Van Rijnsbergen achieved annual savings of €2.675 per trailer by reducing idling and alternator load through solar integration. 

• • Extended battery life:

Battery failure is a common source of breakdowns. Solar systems for trucks provide continuous charging, maintaining battery voltage healthy.  

Battery Life Extension: Up to 3× longer lifespan.

Battery cost:

• • Battery replacement cost (24V commercial battery): ~€350–€500 
• • Standard lifespan: 2 years 
• • Solar-supported lifespan: up to 6 years (3× longer) 

• • Fewer Emergency Repairs and Service Calls 

Dead batteries cause costly emergency service calls and downtime. Solar-supported electrical systems improve reliability, resulting in fewer breakdowns and less unplanned downtime. 

Cost of breakdown due to dead battery: ~€500 - €800 

Myth 3: Myth: Solar panels add a lot of weight 

Fact: Today’s solar panels are lightweight and optimized for transport use. 

For instance, SolarOnTop technology uses ultra-thin, flexible solar panels that weigh 6 kg each. Depending on the application, systems typically consist of 4 to 12 panels, totaling:  

• • 4 panels = approximately 24 kg  
• • 12 panels = approximately 72 kg  

Impact on fuel economy and payload    

Based on field testing and experience with more than 130 vehicles equipped with SolarOnTop, the impact on fuel economy and payload is negligible.  

To put this in perspective:  

• • A typical trailer can carry up to 28.000 kg of cargo  
• • A 72 kg solar system represents only about 0.27% of the total payload of a trailer carrying 28.000 kg.  
• • Since the weight is mounted on the roof, it doesn’t reduce usable cargo space  

Fuel Efficiency  

Real-world testing shows no measurable impact due to the added solar weight. Instead, fleets gain multiple benefits:  

• • Battery life extended up to 3 times longer.  
• • Fewer dead battery service calls.  
• • Up to 5% reduction in energy consumption and decreased engine idling. 
• • Lower maintenance costs and improved fleet uptime.  

Myth 4: you can only use solar in sunny places 

Fact: Solar panels produce energy all day long—even on cloudy days.  

This is a common misconception. While it’s true that solar panels generate less energy in low light or cloudy conditions, new solar panels are designed to operate efficiently throughout the day. Thanks to significant advancements in photovoltaic materials, solar panels now perform better in a wider range of lighting conditions. 

Additionally, advanced solar technologies are paired with batteries that store excess energy, which can be used at night or when sunlight is limited. These innovations make solar technology one of the most reliable solutions. 

Myth 5: Solar technologies are only for electric trucks  

Fact: On-board solar systems support all types of trucks—diesel, hybrid, electric, HVO, LNG  

Trucks and trailers, no matter their main energy source for propulsion, rely on electrical components powered by batteries. On-board solar technologies are designed to charge and support these important systems, regardless of the vehicle’s energy type. 

Myth 6: Solar panels are too fragile for tough conditions and require maintenance 

Fact: Solar panels designed for trucking are built to handle real-world challenges: vibrations, extreme weather conditions, constant road movement... These panels are tested for the toughest environments. 

SolarOnTop by IM Efficiency uses durable, high-performance solar panels specifically engineered for commercial transport. Fleets using SolarOnTop have driven thousands of kilometers across diverse climates, from snowy Scandinavia to the heat of southern Italy and Chile, without system failures or the need for additional maintenance.