Many charging stations do not deliver the power they should: “It’s like heating a thermos from the inside”

Summer is here, and experts predict a heatwave throughout the Nordic region. This means that many electric vehicle owners run the risk of suddenly finding themselves without a fully charged car.
“Many charging stations derate, meaning they do not deliver on the promised power. The DEFA Power charging station is an exception and does not derate at all in our Nordic climate,” says Bård Vestgård, Chief Engineer at DEFA.

Why do charging stations not deliver the desired power? In various Facebook groups and EV forums, there are many questions from electric vehicle owners during the summer months, who experience that their charger doesn’t deliver as promised.

Bård Vestgård, Chief Engineer, explains:
“When a charging station is in use, heat is generated inside of it. In addition, it may also be heated from the outside by the sun. When a charging station becomes very hot and risks overheating, its charging power is reduced. This is what we mean by derating.”

How does derating affect the electric vehicle owner?
“It takes longer to fully charge the car. If the charging power is reduced from, for example, 16 A to 6 A, it takes more than twice as long to charge the car”, says Vestgård.

“Imagine putting your car on charge and expecting it to be fully charged when it’s time to pick up the kids from preschool or leave for the vacation. You expect the charging station to charge at maximum power, even when it’s hot outside. When the car doesn’t charge as planned, it can have consequences. At its worst, derating could mean that the car doesn’t charge at all.”

Which charging station should I choose if I want one that delivers on its promises?
“DEFA Power is designed to always be able to deliver up to the car’s capacity as long as the available electricity in the house allows it. If it’s 35 degrees Celsius outside on a hot summer day, as a DEFA Power user, you will not experience any derating.”

Why does DEFA Power not derate at all?
“Many charging stations on the market are encapsulated by more than one layer of plastic. It’s like heating a thermos from the inside, and that’s obviously not good. DEFA Power has only a single layer of plastic around it, and the design minimizes heat developing inside the box. The unit has an aluminum plate in direct contact with the hot copper inside the charging station. This allows heat to be transported directly from the inside and spread across the aluminum plate. And the wall mount on which the charger is fitted is perforated. It looks like a Swiss cheese, which allows heat to further dissipate from the aluminum plate to the surrounding air. In addition, our electronic components are resistant to high temperatures.”

“We have conducted very detailed analysis and relied on advanced mathematics when designing DEFA Power, to ensure that it delivers without any power loss: we have not only chosen robust design and technology but also placed the different components in exactly the right places.”

What about fans in chargers – is that a good solution for charging station manufacturers facing derating issues?
“Active cooling with a fan blowing and mixing air involves contamination with particles. A charging station must be completely sealed and be able to withstand rain, snow, and dirt in all conditions. We use no active cooling, only passive. DEFA Power does not let any air in or out. This design is perfect for both warmer and more humid weather, as we are heading towards a hot summer.”