As more commercial fleets transition to electric vehicles, facilities, and fleet operators are faced with the challenge of designing an entire charging infrastructure to support hundreds of vehicles. Commercial vehicles typically have larger batteries that need to be charged in a shorter amount of time than your average passenger vehicle.  Therefore, most commercial vehicles are designed to use Direct-Current Fast Charging (DCFC), which can charge a vehicle much faster than a residential AC-Level 1 or AC-Level 2 charger.

Here are three important steps to consider when choosing a DC fast charger for your commercial vehicle fleet:

1. Know your vehicle

Battery voltage and maximum charging current are limits set by the vehicle manufacturer to ensure the health and operation of the vehicle’s battery pack. Before selecting your charger, it’s important to understand the maximum power your vehicle can accept to ensure that you don’t oversize the charger or the associated electrical infrastructure.

For help calculating the maximum power for your vehicle, contact us today!

2. Determine your charging schedule

 Understanding when and for how long your vehicle can charge is essential for fleet planners.

Charging can only occur when a vehicle is parked and not in use. Therefore, operating an electric vehicle fleet requires having a charging schedule in place that specifies when, where, and for how long a vehicle will charge to meet the energy demands during a shift.

Having a charging window that is longer than the time needed to recharge the battery allows for more flexibility in fleet operation, as well as the opportunity to reduce charger power. A reduction in charger power, or a smart charging schedule, can reduce site electrical demand and save on energy costs.

If the charge window is shorter than the recharge time or the vehicle’s battery capacity is too small for a full shift of operation, opportunity charging may be required. In opportunity charging, a high-powered charger is used for a short period of time to replenish battery energy as fast as possible.

3. Calculate charge times

 Estimating the amount of time it takes to recharge an electric vehicle can be complicated. Working with vehicle manufacturers can get you rough estimates on approximate charge times, while accurate charge times can only be obtained through empirical data or computer simulations. Combining the simulated results with your operating schedule can provide the roadmap for charger requirements.

During a charge session, the rate at which the battery is charged will either be limited by the charger or the vehicle. Typically, the first and last 10% of the vehicles’ state-of-charge (SOC) charges at a slower rate than the middle 80%. This is done to protect the health of the battery.

A charger will reduce its power output based on different limiting factors at any given point in the charging session. It is possible that the limiting factor may change over a vehicle’s SOC meaning that it is possible that each vehicle and charger combination will have its own unique charge curve, and therefore charge time.

Let’s get charging

 The three steps listed above can help you get started in the charger selection process. Site limitations including available power, space for charging equipment, and additional infrastructure requirements can further complicate charger selections.

To learn more about how Proterra Energy can help right-size your fleet’s infrastructure, visit our website and contact us today for an initial site evaluation.