You keep making unit mistakes. Charging rate is measured in kW, a unit of power. There's no /h, no /hour, no per hour.
For "31 kW in 1.5 hour", are you talking about 31 kWh? Energy is measured in kWh.
If you charge at 50 kW * 1 hour --> 50 kWh came out of the "wall". Multiply units and...