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.

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

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 Current Transformer Orientation in Relation to Power Flow
  Figure 2. Neurio W2 CT Correctly Oriented to Measure Solar (top) and Incorrectly Oriented (bottom)
Confirm the CT is measuring the correct phase:
1. Locate the CT on the Meter page in Tesla One.
2. Determine which phase the CT should be measuring.
  Note
  If using Gateway CTs, the ports are CT 1 (Line 1), CT2, (Line 2), CT 3 (defaults to Line 1 but can be configured as Line 2 in Tesla One).
  Note
  If using a Neurio meter, the ports are A (Line 1), B (Line 2), B (Line 2), A (Line 1) and are determined by voltage reference.
3. Verify the CT is measuring the correct phase.
  Figure 3. Gateway CT Measuring Correct Phase (top) and Incorrect Phase (bottom)
  Note
  In the examples above, the CT is monitoring a solar inverter conductor, which is why only (1) CT is required.
  Figure 4. Neurio W2 CT Measuring Correct Phase (top) and Incorrect Phase (bottom)
  Note
  In the examples above, the CT is monitoring a solar inverter conductor, which is why only (1) CT is required.
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
  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).
  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 5. 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).