Charge HQ uses a live data feed from one of the solar inverter, home battery or an energy monitor. This data feed is accessed over the internet and provides time series data on how much solar is being produced and in many cases how much is being exported. Charge HQ constantly monitors this data feed then communicates with the EV or wall charger over the internet, instructing it to charge at a rate matching the excess solar energy that is available. You can read more about the minimum hardware requirements, or how the charging control system works.
