Visibility on power and energy data is needed for the Powerwall 3 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.
• Metering Solar – Solar meters capture production from PV inverter(s). There must not be any loads or Powerwalls behind the Solar CTs. This would result in under- or over-estimation of solar production. In this system, Powerwall 3 performs its own Solar metering. Standalone (AC-coupled) solar inverters must be metered by Tesla Remote Energy Meter.

Site and Solar Metering for Backup Switch

Backup Switch makes metering simple with its built-in Site meter (Meter Z). Meter Z may be used for a whole home backup configuration, with no additional steps required during installation.

If there are any loads or solar upstream of Backup Switch, Tesla 200 A CTs connected to Tesla Remote Energy Meter can be used to measure loads / solar less than 200 A; multiple CTs can be used to measure loads/solar greater than 200 A. Tesla 200 A CTs may be extended up to 28 ft (8.5 m) using up to (2) Tesla CT Extension kits (Tesla P/N 2060713-xx-y). See Residential Energy Product Metering Guide for Tesla Remote Energy Meter installation instructions.