Understanding Power Loss in EV Charging

When charging an electric vehicle (EV), many people wonder: Does all the power from the charging station reach the battery, or is some of it lost?

In this article, we explain the process behind power transfer from the charging station to your EV's battery.

Power Networks: Our power grid uses Alternating Current (AC).

EV Batteries: The power stored in an EV's battery is Direct Current (DC).

Since the two types of current are different, a transformation is necessary to make the AC from the charging station suitable for storing in your EV battery.

Inverter Function: This transformation is called inverting.

Familiar to Solar Panel Users: If you have solar panels, you're likely familiar with inverters. Solar panel inverters convert DC generated by the panels into AC that can be used by the power grid.

EV Charging Inverters: The inverters for EV charging work the opposite way: they convert AC from the power network into DC suitable for your car's battery.

The inverting process happens directly in the charging station when using a DC charger. This means the power delivered to the EV battery is already in the correct form (DC).

With AC chargers, the inverting process happens inside the car. The power must first be converted from AC to DC before it can be stored in the battery.

Why It Takes Longer: This is why charging with an AC charger typically takes longer than with a DC charger—the transformation process takes time.

The transformation from AC to DC is a complex process. It’s not surprising that:

10-20% of the power used during charging goes into the transformation process itself. This "lost" power is not wasted; it is used for: Driving the transformation process (AC to DC) Heating or cooling the battery to protect it from damage during charging