Several Misconceptions About Electric Vehicle Charging

The electric vehicle (EV) charging industry has grown rapidly as automakers around the world have pledged to sell only electric vehicles in the future, and governments have helped build fast, reliable charging networks. These EVs will require fast, efficient and powerful EV charging stations.

In this article, we'll clear up some of the misconceptions about EV charging.

Mistake #1: Electric vehicles can be charged directly from AC power.

Yes, there are EV chargers that directly use AC power to charge EVs, such chargers rely on the on-board charger to first convert AC to DC and then use DC to charge the EV battery.

However, some EV chargers also convert AC to DC first, and then do AC/DC conversion without an on-board charger to directly charge the EV battery. Typically, DC chargers operate at higher power levels, so charging times can be shortened.

Mistake #2: All EV charging stations use the same charging technology.

Electric vehicle charging stations use a variety of technologies. Some chargers convert AC power to DC power by using on-board chargers to directly charge electric vehicles with AC power.

However, there are EV chargers (called DC chargers) that first convert AC to DC and then charge the EV battery directly without the need for an on-board charger for AC/DC conversion. AC/DC conversion can use different power topologies.

Mistake #3: EV chargers are all the same power level.

Electric vehicle chargers (aka charging stations) come in a variety of power levels. Levels 1 and 2 are AC chargers up to 20kW. Level 3 contains fast DC chargers typically 50kW and above (up to 350kW).

Mistake #4: Electric vehicle charging stations are operated by the grid or utility.

But in fact, it's not. While grid and utility-run charging stations can operate charging stations, some automakers run their own network of charging stations, and other brands of electric vehicles can also be used.

There are also third-party charging station network operators who are neither utility companies nor EV OEMs.

Mistake #5: High-power-level EV chargers are more efficient.

Power topology, control method, design, and component selection have a significant impact on the overall efficacy of a charger. For example, zero-voltage switching and zero-current switching power supply topologies can greatly reduce switching losses and thus improve power efficiency.

On the other hand, low power class chargers are not more efficient than high power class chargers. Low-power-level chargers rely on on-board chargers to convert AC to DC power before charge an electric car battery. Since the efficacy of a charger is determined by a variety of components, it is not clear that one charger power level is more efficient than others. Typical efficiencies are between 95% and 99%, depending on implementation.

Mistake #6: High-voltage EV chargers are notoriously unreliable.

With the advent of new battery technologies, the voltage of car batteries can reach 800V and above. Following this trend, EV charger designers will face a common problem of maintaining isolation levels and system reliability.

Solar technologies (photovoltaic inverters) with DC bus voltages in the 1,000V to 1,200V range are widely used in electric vehicle charging designs. These isolation technologies have been proven for over a decade and are well known for their reliability.

Mistake 7: Electric vehicle charging still requires the driver to go to a charging station to "power up," just like going to a gas station to refuel.

There are now many different ways to charge at home, and consumers can choose to automatically charge their EVs when electricity bills are lower, such as at night. Most modern homes or homes with garages are equipped with a 240V plug that will give you 100 to 200 miles of range on a charge.

Even an ultra-low-power charger installed in a home garage that connects to a standard 120V plug can achieve a range of 40 to 60 miles after an overnight charge. For most drivers, charging at home every day is the easiest and most convenient way to charge.