Power measurements are needed for a Powerwall or Solar Inverter system to operate properly, and for system data to appear in the customer's Tesla app. An energy meter accomplishes this by measuring voltage (by voltage tap) and current (by Current Transformer) at key locations in the system.

Current Transformers (CTs) are installed around conductors to monitor the current flowing through them. The CTs are connected to a meter which sends the measurements to the system's Site Controller. Using this current measurement, the system calculates power measurements to determine how much power the customer is using, or how much power the PV system is producing. The power values are then displayed in the customer app and are used by the system to operate as configured by the customer. For instance, a customer may want to store their solar power for use at night. CTs measure both solar production and the home's power consumption so that the system knows how much solar to store during the day and supply at night.

In the example below, CTs within Backup Gateway 2 measure home power consumption, and a CT connected to Backup Gateway 2 measures solar production.

See Metering Options for an overview of each measurement type and the available meters and CTs for that measurement type.