If you have ever plugged in an electric vehicle late at night, you might have noticed a strange sound. Some people think of it as a low, steady hum that sounds like a bee trapped in a jar. But for others, it sounds like a tiny jet engine taking off in the driveway. It’s normal to feel a bit nervous when a piece of high-voltage equipment starts making noise. This is because we usually expect electronics to be silent like our cellphones. However, moving significant amounts of electricity is a heavy job that creates physical reactions. Under normal conditions, a charger’s noise is a sign that the hardware is doing its job to keep your battery healthy and full for your morning commute.
Heat Is the Main Reason for the Whirring
When electricity moves from your home’s wiring and into your car’s battery, some of that energy turns into heat. High-speed chargers, called Level 2 chargers or DC fast chargers, push a lot of energy very quickly. This creates a considerable amount of warmth. To keep the internal parts from melting or wearing out, many chargers have built-in cooling fans that spin at high speeds. These fans pull in cool air and push out the hot air so that the devices stay within a safe temperature range.
The Reason for the Electrical Hum
You may have walked past a large green transformer box on the sidewalk and heard a vibrating buzz. This sound is called “coil whine.” It happens because of electromagnetism. Inside your charger, coils of wire create magnetic fields as electricity flows through them. These magnetic forces can cause the metal parts inside the charger to vibrate back and forth extremely fast. Since these vibrations happen hundreds of times every second, they create a sound that our ears hear as a constant hum or a high-pitched whistle. If your charger is older or has loose parts inside, this humming might be louder than that of new model that is tightly sealed.
Why Some Units Stay Completely Silent
If your neighbor has a charger that never makes a sound, they might be using a lower-power Level 1 charger or a unit with passive cooling. Smaller chargers that plug into a regular wall outlet move electricity slowly. This means they do not create nearly as much heat as the bigger and faster chargers. Since there is less heat, these devices can rely on heavy metal shells called heat sinks to soak up the warmth and release it into the air without needing a fan. These silent chargers are great for people who sleep near their garage. However, the trade-off is that they take a much longer time to fill up the battery. If you live in Lexington, KY or a surrounding area and need EV charger services, make your first call to Absolute Services.