On-Board Charging for Class I and Class II Lift Trucks

This is a summary from the presentation by the same title by Conway Hui, Director of Sales Application Engineering and Customer Support at Delta-Q Technologies, at the Future of Electrification 2023 conference. Watch the full session here:

As industries grapple with sustainability and efficiency mandates, the focus on battery charging technologies—especially for Class I and Class II lift trucks—has intensified. 

The Key to Navigating the Transition: Standardization

End users increasingly favor electric Class I and Class II lift trucks over internal combustion (such as propane and diesel). While traditionally utilized in warehouse spaces due to easy integration of charging infrastructures, the role of all-electric lift trucks in external scenarios has been constrained due to logistical charging challenges.

This is changing.

Shifting regulatory stances, such as the EU's Stage Five emissions restrictions, and the accompanying need for sustainable corporate practices, are escalating demand for electric lift trucks. Beyond regulatory adherence, users appreciate the additional advantages offered by such systems:

• Quieter operations 
• Decreased emissions 
• Reduced upkeep costs

Identifying this heightened need for versatility and sustainability, Delta-Q Technologies is driving innovative on-board charging solutions. These are poised to redefine the role of electric lift trucks—expanding their applications into areas such as construction, delivery, and rental.

Technical Hurdles: Design and Environmental Challenges

Taking Class I and Class II electric lift trucks from the predictable environments of warehouses to the unpredictable outdoors introduces new complexities:

• Durability – On-board chargers must be built to combat outdoor weather, as well as the shocks and vibrations from driving through rough terrain and urban environments.

• Charge constraints – Charging for on-board systems typically hovers around 6-7 kW—a marked contrast to the 10-20 kW provided by off-board alternatives. This constrained rate also means more time to reach full charge, especially for larger batteries.

• Compatibility – While ensuring synchronization between the charger and battery is crucial, charger-telematic integration is a close priority.

Connectivity and Charging Standards

With a range of potential outlets and inlets available, yet limited on-board space to utilize, the choice of charging connector matters:

• Universal EV connectors, such as North America's J1772 and Europe's Type 2, facilitate the charging process via prevalent infrastructures like standard wall outlets and L14-30 outlets.
• CCS and CCS Combo ports add DC voltage for faster charging capabilities, ranging from 50-400 kW (greatly outclassing the standard connector’s average of 6-7 kW).

While DC output connectors provide the fastest charge, finding a compatible charging station is currently a rarity. Until DC fast chargers become more widely adopted, standard EV connectors and EVSE adapters remain the most pragmatic solution.

Meeting the Challenges: Practical Advice from Delta-Q

Developing adequate on-board charging solutions requires intelligently navigating known challenges and potential surprises. For OEMs and fleet owners seeking to maximize the versatility and sustainability of their Class I and Class II lift trucks via electrification, consider the following approaches:

• Upgrade batteries – Utilize lithium-ion batteries as opposed to lead acid. In addition to reduced maintenance, energy-dense lithium-ion frees up additional space to incorporate modularized on-board chargers, such as the Delta-Q XV3300.
• Maximize connector space – Rather than attempting to incorporate multiple connectors, focus solely on EV-style AC charge inlets. This maximizes on-board space while minimizing the internal complexity of integrating communication circuits.
• Verify voltage requirements – Auxiliary voltage specifications can vary among Class I and Class II vehicle manufacturers. It is necessary to maintain a 12-volt output to facilitate communication with the EVSE interface, achievable either via a small 12-volt battery or a DC-DC converter.
• Educate operators – Given that charge times are primarily influenced by site-specific power availability, setting proper expectations for customers and end users may be helpful. Fully charging a 50 kW battery pack at a low power charge rate of 3.3 kW would take approximately 15 hours, for example. Such insights help users plan better.

With solid optimization strategies in place, the transition from traditional combustion engines becomes a manageable task, ensuring a fleet that is ready for the road ahead. 

Summary and Takeaways

Electric lift truck deployments are anticipated to grow. In addition to the apparent benefits of quiet operation and lowered maintenance costs, there are other factors driving this trend:

• Regulatory changes
• Sustainability initiatives
• The need for lift trucks in external applications

While there are challenges involved in the shift to electric drive, they are not insurmountable. Understanding available options, and then matching battery type, on-board charger, and charging connectors with the environment the vehicle is anticipated to encounter are the foundational pillars of optimization.

From technical challenges to design considerations and the symbiotic relationship with battery technologies, Delta-Q leads by example in educating end users and fleet operators alike—driving the charge toward a sustainable future.