Typical EV Charging Use Cases for Light-Duty Chargers
Joseph Gottlieb, CTO, Tuesday Sept 28, 2021)
One question I hear a lot is why can’t home chargers or light-duty (LD) commercial chargers be used for medium- and heavy-duty (M/HD) electric vehicles. To best answer this question, you need to understand the typical use case for home and LD chargers. Let’s start with the LD vehicle daily mileage and usage. According to the US DoT, the average vehicle is driven slightly under 30 miles per day. Depending on the size of the vehicle, this represents 9kW-15kWh of energy usage per day. It would take the average home Level 2 AC charger (slightly under 10kW of charging capacity) between 1 and 1-1/2 hours to charge one of these vehicles. These devices are typically under $1,000 in cost.
The use case for AC commercial chargers (the ones that you find at shopping centers or workplaces) is similar. The role of these chargers is to “top off” cars while consumers are shopping or working. If the average daily mileage in the US is 30 miles, then the average one-way distance to a workplace or shopping mall could be construed to be 15 miles on average; this represents 4.5-7.5kWh of energy usage. Most AC commercial chargers (which typically cost around $8,000-$10,000 for a dual-port charger) have power output levels of 7.2kW per port. If you are shopping for an hour, one of these chargers could top your car off in 40 minutes to an hour. If you are charging at work (and even if you only use the charging space for half the day), most of the time the charger is connected to your vehicle it is not operational. And that is one of the defining characteristics of AC chargers – they are used in situations which are characterized by non-use most of the time, and with relatively low power output when used. Next week we will look at the use case for M/HD EVs, and why the characteristics of AC Level 2 chargers are not suited to supporting these vehicles.
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