To determine if your panel power meter is accurate, follow these steps:

Calibration:
Ensure your power meter is properly calibrated according to the manufacturer's instructions. Calibration is often necessary to maintain accuracy.

Compare with a Known Accurate Meter:
Use a known accurate and reliable power meter as a reference. Compare the readings from your meter with the reference meter under the same conditions.

Consistency Check:
Check for consistent readings over time. An accurate power meter should give consistent readings under the same conditions.

Manufacturer Specifications:
Review the accuracy specifications provided by the manufacturer. Ensure your power meter's readings fall within the specified accuracy range.

Environmental Conditions:
Ensure that environmental conditions (temperature, humidity, etc.) are within the operational limits specified by the manufacturer. Extreme conditions can affect accuracy.

Load Test:
Perform a load test using a known load (e.g., a resistive load like a space heater). Measure the power consumption with your meter and compare it to the expected power consumption of the load.

Regular Maintenance:
Ensure your power meter is regularly maintained and serviced as per the manufacturer’s recommendations. Wear and tear can affect accuracy over time.

Third-Party Testing:
Consider having your power meter tested and certified by a third-party laboratory if you require high accuracy for critical applications.

User Reviews and Feedback:
Research user reviews and feedback for your specific power meter model to see if others have reported accuracy issues.

Firmware Updates:
Check for and install any firmware updates provided by the manufacturer, as they may address accuracy issues.
If you find discrepancies in the readings, contact the manufacturer for support or consider getting a professional calibration service.

PAC2110 Multi-Function Smart LCD Panel Digital Power Meter