Summary: Comparing Various EV Charging Use Cases

Rick Sander, CEO, Tuesday November 30, 2021

Over the last two months, our blogs have explored a number of EV charging use cases: light-duty (LD) EV charging, public transit e-bus charging, e-school bus charging, refuse truck charging, metro delivery EV charging, federal vehicles, and “remote” (construction, military) EV charging. The “numbers” comparing these classes vary widely, as shown below:

Vehicle Class

Gross Weight

Energy Use
Time to Charge
(60kW Charger)
Light Duty (LD) <8,500 lbs 50-100kWh 5-10kWh <10 minutes
School Bus 14K-36K lbs 150kWh (typ) 125kWh 2 hrs
Construction/Military 40K-60k lbs 100-500kWh <100kWh 2 hrs
Metro Delivery Vehicle 14K-33K lbs 150-300kWh 125-250kWh 2-4 hrs
Refuse Truck 33K-50K lbs 221-400kWh 200-360kWh 3.5-5 hrs
Public Transit Bus 30K->40K lbs 300-600kWh 250-600kWh

4-10 hrs

Clearly, these charging use cases represent an extremely wide range of needs, with a nearly 60X range on daily energy use and “time to charge”, but except for the LD EV class, all of these vehicles really need DC fast chargers to be able to charge in a reasonable amount of time. One trend that is relevant is how EV charger reliability becomes more critical to fleets as vehicle size (and price) increases. There are two reasons for this: a) longer charging times tend to reduce the likelihood that an “extra” charger can be easily found if one fails (unless fleet operators overbuy their chargers); and b) the “wear” on the charger increases as the charging times grow. This is why high-reliability chargers are so important for medium- and heavy-duty vehicles.

And if you are looking for high-reliability, made in the USA high-power DC fast charging systems for your M/HD EV fleet, look to Rhombus Energy Solutions. Our market-leading bi-directional EV charging systems (which are designed from the start for the needs of fleet operators) are designed and built in the USA. Rhombus also excel in the design of high-power smart inverters for next-generation renewable energy and energy storage deployments. Our expertise in energy management system (EMS) software is also embedded in our VectorStat EMS controller and software which is embedded in our EV charging systems and smart inverters. We have built over a thousand V2G-capable high-power, high-reliability chargers and bi-directional smart inverters for a variety of different sizes and classes of EVs.

Find out how we can help you by contacting us at, or by reading our Vehicle to Grid Solution Brief.