Medium and heavy-duty fleet electrification now represents a growing segment of commercial transportation. Higher charging power levels, larger battery capacities, and longer duty cycles are becoming standard design considerations. These shifts place new demands on voltage architecture, thermal management, interconnection strategy, and overall site electrical planning.
Raj Jhaveri, CTO of Greenlane
Infrastructure design now requires coordination between vehicle capability, grid availability, and long-term scalability. Power delivery, hardware selection, and phased utility upgrades must align to avoid costly retrofits and operational constraints.
In Part I of this Q&A, Raj Jhaveri, Chief Technology Officer of Greenlane, discusses how charging power evolution is influencing voltage planning, grid-aware site design, and hardware requirements for high-power freight applications.
Part II will examine grid interconnection and power-quality considerations, deployment lessons from early installations, and the technical tradeoffs engineers must evaluate when balancing charging speed, reliability, and total cost.
Here’s what Jhaveri has to say…
How are medium and heavy-duty charging requirements reshaping voltage levels and power architecture?
As charging expands into medium and heavy-duty applications, power requirements are increasing substantially. Unlike light-duty deployments that evolved incrementally, many charging infrastructure strategies are now engineered from the outset specifically for larger vehicles, with voltage, power, and site configurations designed to support their unique operational demands.
What’s evolving most rapidly isn’t just power levels, but a more refined understanding of how different duty cycles require different charging solutions. A key distinction is emerging between vehicles that park for extended periods, such as tractor-only units staged in yard lanes, and vehicles that need to charge quickly and return to service via pass-through lanes.
Tractor-only or extended-dwell applications typically require lower power levels, up to approximately 240 kW, which are well suited for vehicles with predictable parking windows. In contrast, pass-through lanes are designed for higher throughput and faster turnaround, supporting 400-kW charging today. Importantly, many of these lanes are being prepared to accommodate Megawatt Charging System (MCS) standards, anticipating the next generation of vehicles.
Battery capacities in the current market already vary widely. Some vehicles can accept approximately 275 kWh, while others, depending on battery configuration and dual-port capability, can handle up to 800 kWh.
Freight charging hubs are being engineered with scalable electrical architecture to support 400-kW charging today and future megawatt-class vehicle platforms.
As newer models enter service with megawatt charging capability, vehicles are increasingly designed to support 800 to 1,000-kWh charging rates. That shift significantly impacts site design, including transformer sizing, switchgear, cable management, thermal management, and overall load planning.
How are grid constraints influencing large-scale, heavy-duty charging site design?
In practice, power availability is often governed as much by grid realities as by vehicle capability. Most utility providers deliver capacity to large charging sites in phases rather than all at once. As a result, infrastructure must be engineered to scale alongside phased utility upgrades. This requires modular electrical design, expandable switchgear, and careful master planning to avoid costly retrofits as capacity increases.
To address grid constraints and improve resilience, microgrid solutions are increasingly part of the design conversation. Onsite energy storage, managed load balancing, and in some cases renewable integration allow sites to smooth peak demand, optimize available capacity, and reduce strain on the local grid. These solutions are especially important at high-power freight corridors, where simultaneous megawatt-level charging events can create significant demand spikes.
By integrating energy management systems and storage from the outset, sites can operate efficiently even before full utility build-out is complete.
More broadly, the industry is moving away from a “build it and they will come” mindset toward right-sized, demand-driven deployment. Rather than installing large numbers of chargers upfront, developers are designing sites that can scale over time. Site selection prioritizes locations with viable grid access to accelerate deployment, while engineering teams plan for current constraints and future megawatt-scale expansion.
Corridor identification is also becoming more data-driven, using real-world freight movement patterns to ensure voltage levels, charger configurations, and site layouts align with where electrification is most likely to scale first.
How do higher charging powers affect thermal management, cable design, and connector selection in public charging networks?
At 350 to 400 kW, thermal management is already a critical design consideration. Sustained high-current delivery generates significant heat not only in the cable and connector, but also within power electronics, busbars, and switchgear. When you move into megawatt-level charging under MCS, those thermal loads increase substantially. Liquid-cooled cables are becoming essential rather than optional, and cooling systems must be designed for continuous heavy-duty operation rather than intermittent passenger vehicle use.
For Class 8 vehicles in pass-through lanes, charging events can involve very large energy transfers in relatively short timeframes. That sustained load profile requires advanced thermal monitoring, active cooling systems, and redundant safety controls to ensure connectors and cables maintain safe operating temperatures under high ambient conditions and repeated use.
Cable design also becomes more complex at higher power levels. Megawatt charging requires larger conductors to handle increased current, but usability cannot be sacrificed. Cables must remain flexible and manageable for drivers while containing liquid cooling channels and insulation capable of withstanding higher voltage architectures. Strain relief, cable routing, and retracting systems become important parts of site design to prevent wear and ensure safe handling in high-traffic freight environments.
Connector selection is similarly impacted. As fleets transition gradually from CCS to MCS, public charging networks must accommodate standards without compromising utilization. CCS/MCS-compatible or modular dispenser designs allow operators to serve today’s vehicles at 350 to 400 kW while preparing for future megawatt-capable trucks. MCS connectors are physically larger and engineered for higher current density, requiring reinforced mounting, more robust latch mechanisms, and precise thermal integration to maintain performance and safety.
Higher charging powers also influence overall site electrical architecture. Power cabinets must dissipate more heat, often requiring enhanced airflow or liquid-cooled internal systems. Transformers, switchgear, and protection systems must be rated for higher fault currents. As multiple trucks charge simultaneously at high power, intelligent load management becomes critical to balance demand across dispensers while operating within phased utility capacity constraints.
An additional factor in heavy-duty charging environments is the electrification of trailers, particularly refrigerated units (eTRUs). While trailer refrigeration loads are significantly lower than propulsion charging, they may operate simultaneously with tractor charging and introduce additional continuous demand at the site. Providing dedicated lower-power connections for trailer systems, separate from high-power CCS or MCS dispensers, helps optimize utilization while avoiding unnecessary strain on megawatt-capable infrastructure.
High-capacity battery-electric tractors can transfer several hundred kilowatt-hours in a single session, placing significant demands on cooling systems, cabling, and site-level power management.
As fleets electrify tractors and trailers, charging sites must account for multiple load types operating in parallel, reinforcing the need for flexible distribution design and advanced energy management systems.
From a layout perspective, higher power levels also influence vehicle spacing, cable reach, and equipment placement. Pass-through lanes designed for high-speed freight operations must accommodate larger vehicles and safe cable handling zones, while dwell-oriented bobtail lanes operating at lower power levels, up to approximately 240 kW, experience less thermal stress but still require scalable infrastructure planning.
What grid interconnection and power-quality considerations are more critical as charging sites support higher loads and longer duty cycles?
At a fundamental level, grid capacity and interconnection timelines often dictate deployment schedules. Utility infrastructure varies significantly by location, and most utilities deliver capacity to large sites in phases rather than all at once. That means charging hubs must be engineered with modular electrical architectures that can scale alongside phased utility upgrades, incorporating expandable switchgear, transformer capacity planning, and space allocation for future equipment. Without that foresight, sites risk costly retrofits as demand increases.
As power levels rise from 350 to 400 kW into megawatt charging under MCS, peak demand spikes become more pronounced. Simultaneous charging of multiple Class 8 vehicles can create substantial instantaneous loads, particularly in pass-through configurations designed for high turnover. Longer dwell times in bobtail lanes introduce sustained load profiles that further stress local distribution infrastructure. Engineering teams must carefully evaluate feeder capacity, substation proximity, and protection coordination to ensure reliability.
Power quality becomes increasingly important at these higher loads. High-power dc fast charging can introduce harmonics, voltage fluctuations, and reactive power impacts on the local grid. As charging hubs scale, mitigation strategies such as harmonic filtering, power factor correction, and advanced inverter design become critical to maintaining compliance with utility standards and avoiding disruption to surrounding customers. Protection systems must also account for higher fault currents associated with megawatt-scale infrastructure.
Load management also plays a critical role in stabilizing grid interaction. Intelligent energy management systems can dynamically allocate power across dispensers, reducing peak demand and smoothing load curves. This becomes even more important as fleets begin electrifying tractors and auxiliary systems, such as refrigerated trailers, which may introduce continuous secondary loads alongside propulsion charging.
To address grid constraints and improve resilience, microgrid solutions are increasingly integrated into site design. Onsite battery energy storage systems can buffer peak demand, reduce demand charges, and allow sites to operate effectively before full utility build-out is complete. In some cases, distributed energy resources such as solar can supplement site energy profiles, though most large-scale commercial freight hubs will continue to rely primarily on grid supply for base load requirements.
Flexible interconnection models, including managed charging agreements or non-firm capacity arrangements, show promise for accelerating deployment. However, broader adoption will likely require more standardized regulatory frameworks to provide predictability across utility territories.
Part II will further explore grid interconnection, power quality, and infrastructure tradeoffs.
Filed Under: Charging, Featured Contributions, High Voltage Systems (> 60 VDC), Q&As