Question about Ctek MXS 5.0 EU-Version

If you mean the power source, then it is the standard 250 watts.

According to the test report, a maximum of 250 watts, depending on the charging phase.
On average, it is approx. 60 watts.

If the charger has to charge at maximum power, how much power is required from the socket

The question is more likely to be how large the receiver battery is and whether this device is suitable for it. You may need to define your question a little more precisely.