Why Is My BYD Charging Slower Than the Charger Rating?

You bought a 7kW BYD charger, but your car is showing only 5kW or 6kW.

Is something wrong?

Not necessarily.

The advertised charger rating represents the maximum available output, not a guaranteed charging power under every condition.

1. Your BYD May Have a Lower AC Charging Limit

The first thing to check is your vehicle's maximum AC charging power.

If the car can accept a maximum of 7kW, a 22kW charger cannot force it to charge faster.

2. Voltage Can Affect Charging Power

Charging power depends on voltage and current.

If the voltage at the charging location changes, the actual power can also change.

For example:

Power ≈ Voltage × Current

Therefore, a charger operating at a lower-than-expected voltage may not reach its advertised maximum power.

3. The Charger May Be Set to a Lower Current

Many portable EV chargers allow users to adjust the charging current.

For example, if a charger is capable of 16A but is configured to operate at 10A, the charging power will naturally be lower.

This can be useful when charging from electrical systems with limited capacity.

4. The Home Electrical System May Limit Charging

If the electrical installation cannot safely support the required current, the charging system may limit power.

This is why the charger, socket, wiring, and circuit breaker all matter.

5. Charging Conditions Can Change

Actual charging power can also be affected by:

√ Battery state of charge
√ Battery temperature
√ Vehicle charging management
√ Voltage fluctuations
√ Charger temperature
√ Electrical losses

Charging may also slow as the battery approaches a high state of charge.

What Should You Check?

If your BYD is charging slower than expected, check:

1. Vehicle AC charging limit
2. Charger current setting
3. Voltage
4. Electrical circuit
5. Battery state of charge
6. Charging temperature
7. Charger specifications

Final Takeaway

A 7kW BYD charger does not guarantee that your car will always charge at exactly 7kW.

The actual charging speed depends on the entire charging system.

If the power is consistently much lower than expected, check the vehicle settings, charger configuration, and electrical installation before assuming that the charger is defective.