AC Power Required to Start Charge

[NightFox]

Does anyone know how much AC power the I-Pace requires before it will start a charge? I know the charging standard sets a minimum charge level of 1.4 kW, but my I-Pace won't start charging off my zappi 2 (in its Eco+ solar excess only mode) until there's about 1.8 kW surplus, but then it's happy charging till the surplus drops below 1.4 kW again. The 1.8 kW threshold doesn't seem to be something that's set within the zappi.