Negative Solar Reading

On the landing page, the Solar value is negative and does not match the solar production reading from the inverter

Symptoms

On the landing page, the solar value is negative and does not match the solar production reading from the inverter.
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Note
For multi-product installations, see Negative Loads Alert for Multi-Product Installation.
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Note
To troubleshoot this issue, measure solar production using one of the following methods:
  • For Tesla Solar Inverter, use the Solar Inverter Configuration Interface or measure with a multimeter
  • For a third party inverter, use the display on the inverter itself (if present), the inverter production monitoring app, or measure with a multimeter

Steps to Troubleshoot

  1. Confirm the CT is facing the correct way:
    1. Locate the CT(s) used to measure the source that is displaying incorrect power flow readings.
    2. Verify the CT(s) are oriented such that the label is facing toward the source (away from the breaker).
      1. Solar Current Transformer: Label toward the inverter
      2. Site Current Transformer: Label toward the Grid
        Figure 1. Tesla 100 A CT (for Backup Gateway 2) Orientation in Relation to Power Flow
        Figure 2. Neurio W2 CT Correctly Oriented to Measure Solar (top) and Incorrectly Oriented (bottom)
  2. Confirm the CT is measuring the correct phase:
    1. Locate the CT on the Meter page in the Device Setup interface in Tesla One.
    2. Determine which phase the CT should be measuring.
      • Backup Gateway 2 with Tesla 100 A CTs:
        CT1Line 1
        CT2Line 2
        CT3Defaults to Line 1 but can be configured as Line 2 during device setup in Tesla One
      • Neurio Remote Energy Meter with Neurio CTs:
        CT1Line 1
        CT2Line 2
        CT3Line 2
        CT4Line 1
    3. Verify the CT is measuring the correct phase.
  3. Ensure the CT has been placed in the correct location and is measuring the correct conductor(s):
    1. Verify the CT is clamped properly around the intended conductor(s).
      Warning IconA warning icon, calling your attention to a possibly risky situation
      Warning
      Before installing, disconnecting, and/or adjusting CTs, ensure the circuits being measured are not energized and the system is completely powered down. Failure to de-energize the system may compromise operator and equipment safety.
    2. Verify the CT is not capturing any other conductor(s).
      Informational PurposesAn informational icon, calling your attention
      Note
      If a site has multiple inverter outputs and their conductors are being grouped, ensure every conductor is captured.

      In the first example below, the CT captures the (3) L1 conductors for three solar inverters. In the second example, the CT captures (2) solar inverter conductors and (1) hot tub conductor, leaving the third solar inverter conductor uncaptured.

      Figure 3. Solar CT Measuring all PV (top) and Solar CT Measuring Partial PV and a Non-Solar Load (bottom)
    3. If solar is in a generation panel where the only conductors are solar, the entire generation panel can be measured:
      1. If there are additional 120V loads in the downstream panel, move them all to the same phase (in the example below, they are moved to L2).
      2. Move the Neurio meter and CTs to the upstream panel and place the CT on the downstream panel feeder, choosing the opposite phase (in the example below, the CT is placed on L1).
      3. Configure the CT as Solar (1CTx2).