Appendix F: System Energy Metering

Visibility on power and energy data is needed for the Powerwall+ system to operate properly. An energy meter accomplishes this by measuring voltage (by voltage tap) and current (by Current Transformer, CT) at certain points in the system.

There are many possible configurations for installing metering depending on system design. However, there are two goals:
  • Metering the Site – Site meters show the overall power flow to/from a site from the Grid’s perspective. Thus, Site meter(s) must be installed upstream of all solar production, Powerwalls, and loads. Backup Switch makes metering simple with its built-in Site meter (Meter Z), which may be used for a whole home backup configuration, with no additional steps required during installation.
    Informational PurposesAn informational icon, calling your attention
    Note
    If there are any loads or solar upstream of Backup Switch, see Installing a Neurio Remote Energy Meter for instructions to install a Neurio meter and CTs.
  • Metering all Solar – Solar meters capture production from PV inverter(s). A solar meter is factory installed in the solar assembly, with a Solar CT factory installed around the solar assembly AC power conductor.
    Informational PurposesAn informational icon, calling your attention
    Note
    When the site has an additional solar inverter, an additional Solar CT must be installed to measure the inverter's production. If the additional solar inverter is within 15 ft (4.5 m) of the factory-installed Neurio meter in the Powerwall+ solar assembly, the additional Solar CT can be plugged into the factory-installed meter. Otherwise, an additional remote energy meter must be installed and the Solar CT plugged into the new meter. Installing a Neurio Remote Energy Meter outlines installing a Neurio remote energy meter to meter additional solar.