As fleet managers transition their vehicles to electric, it's important to understand that designing an EV charging infrastructure should fit your vehicle and operational patterns, as fleet charging isn't one size fits all. Let’s clear up some misconceptions about the charging process, as EV charging is fundamentally different from gas refueling.
One of our clients' drivers mentioned that never having to go to the gas station is a key benefit because it does not disrupt the workday. Stationary or parked vehicles can use Level 2 charging, but the amps required might vary. On the other hand, vehicles running three shifts a day and making a few short stops in different locations might require Direct Current Fast Charging (DCFC) as the best option.
Utilizing Downtime for EV Charging and Battery Health
Fleet operators can charge their vehicles when they're not in use, which can lead to increased efficiency and reduced downtime during the day. This is a win-win for both fleet managers and drivers. By plugging in before work, running errands, or getting rest, the vehicle is more likely to be ready to go by the time you need it.
Manufacturers typically recommend charging to 80% state of charge (SOC) to help prolong the life of standard NMC-chemistry batteries (Nickel Manganese Cobalt), but this is evolving as other chemistries like LFP (Lithium Iron Phosphate) become common. Charging the battery to 100% for extended periods puts more stress on the cells, causing them to degrade faster over time. By charging to 80%, you are provided with enough range for most daily use, while still leaving a buffer for unexpected trips or emergencies.
Comparing Charging Speeds: Level 1, Level 2, and DCFC
Our team has seen that a large majority of fleet vehicles stay parked for at least 15 hours, which is enough time to charge some vehicles to 80% using Level 2 chargers. The charging speed varies depending on the EVSE setup. For example, a Ford F-150 Lightning Extended Range (that carries a massive 131 kWh battery) can be charged to 80% in that time frame with an 80A, 40A, 32A, or higher output Level 2 charger. It could even charge to 100% with the 80A and 40A in that same amount of time, though this may not be necessary.
The graph below shows how long it would take to charge the same electric pickup, starting from the slowest charging level (Level 1, 12A, 120V) to the fastest (DCFC, 150 kW).