What if your EV charger is slow?

Hello, this is Honest Electric Ltd.

Today, we are going to learn about what to do when your EV charger is slow.

There are 3 parts of EV charging system.

1. Breaker that is installed in your electric panel

2. Wiring between breaker to your EV charger

3. Your EV charger itself or the receptacle that is installed in the end of the wiring

The first thing to check is the circuit breaker installed on the electrical panel. In the case of the circuit breaker of the EV charger, since it is a device that operates continuously for a long time, not for a short time, it is installed with a margin of 125% according to the construction code. That is why a 32A charger has a 40A circuit breaker. If this margin is not there, the charging speed may decrease and the circuit breaker may go blown due to heat generation during charging.

The next specification to check is the wiring from the circuit breaker to the EV charger. The thickness of the wiring should be chosen to be the thickness that can receive the maximum capacity of the circuit breaker. According to the construction code, copper is #8 and aluminum is #6 for 40A.

The last thing to check is the charger body or outlet installed at the end of the wiring. You should use good quality products for both the body and the outlet so that you do not have to worry about slowdowns or heat generation during charging.

In the case of the outlet, if the quality is good, the tightness of the receptacle when plug is inserted is good, so there is less resistance, and thus less heat generation. In the case of a good quality charger, the susceptibility to stress of the internal components is high, so even if the same current flows, there is less heat generation, and the design is designed with heat dissipation in mind, so there is no problem even when using it for a long time.

Also, one more thing to add is that if the installer did not tighten the wiring with enough force during installation, heat generation may occur in that area, current may decrease, and fire or charging speed decreasing might occur. So, it is critical to hire a professional electrician. Aluminum wiring has a higher probability of problems, so a thorough installation is necessary.

Lastly, the reason why I hope you read enough reviews on the Internet before purchasing a charger is that, for certain chargers, the maximum charging speed may be much lower than the advertised specifications.

If you have checked all of this, but the charging speed is slow, you should be aware that all chargers in this world have to slow down the charging speed as they get closer to being fully charged, both electrically and physically. This is because the charging speed decreases as it gets closer to being fully charged in terms of hardware/software, and physically, according to the V=IR formula, the voltage difference between the battery and the charger decreases as it gets closer to being fully charged, which reduces the current. It is normal for the charging speed to slow down when close to fully charged.