Sig Energy Topic

Author	Message
gaspo Regular Member Joined: 25/06/2018 Location: Australia Posts: 67	Posted: 02:00am 23 Dec 2025         wiseguy said   I haven't had the top cover off mine yet - probably the first thing I've ever owned and not done that. I assume that was required to get access to the connector in question? I was not aware modbus was an available option over the ethernet, you made good use of it. Does the ESP32 retransmit the inverter information via WiFi with the combined inverter plus your temperature value? There is no need to remove the plastic cover. The back of the inverter, where all the connectors are located, is already open and can be accessed by hand from the rear. The temperature module I built is independent of the Sigenergy data. It uses an ESP32-C3 running MicroPython code and publishes temperature data via MQTT (over WiFi) to Home Assistant. In Home Assistant, I defined a new sensor that subscribes to the MQTT topic published by the temperature module, and this sensor is displayed on one of the dashboard cards.   wiseguy said   I also made an incorrect assumption that the gateway unit was the WiFi point for the Sig, but the inverter itself has a WiFi antenna, so it appears the gateway communicates over I am guessing canbus or modbus or ethernet, data back to the Sig inverter for WiFi relaying? Yes, the WiFi module is integrated into the inverter and uses a version of the ESP32. The gateway connects to the inverter via an Ethernet cable, while the second Ethernet port on the inverter is used to connect to my local network. Modbus over Ethernet also works when the inverter is connected only via WiFi.   wiseguy said   This morning I took a look at the inverter data page and noticed some weird information. Maybe Gaspo (anyone?) can tell me what it is up to, here is the page; The house load was about ~380W at the time yet phase 1,2 & 3 all have ~5A of current at ~240V the reactive power was ~4kVAR, reported power factor was ~.091, which when multiplied by the ~4kVAR equates to the ~380W of consumption. I don't fully understand how various AC powers work in the grid connected inverters. So I asked ChatGPT for inverter power analysis of my data: Active power: 2kW Reactive power: -1.7kVar Phase A current 11.5A Phase A Volts: 243 Power factor: 0.755 1. What each value means Phase A Volts: 243 V Normal Australian single-phase grid voltage (230 V nominal, ±10% allowed). Phase A Current: 11.5 A The RMS current flowing between the inverter and the grid. Active Power (P): 2 kW This is the real, useful power that actually does work   - Running appliances   - Charging batteries   - Exporting to the grid Formula: P=V×I×cos(φ) This is the power your meter bills for. Reactive Power (Q): −1.7 kVAr Reactive power is power that oscillates back and forth between the inverter and the grid and does no net work. It comes from:    - Inductors (motors, transformers)    - Capacitors (filters, inverter output stages) Power Factor (PF): 0.755 Power factor tells you how efficiently current is being used. Formula: PF=P/S Where: P = Active power (kW) S = Apparent power (kVA) A PF of 0.755 means: Only ~75.5% of the current is producing real work The rest supports reactive power 2. What does negative reactive power mean? This is the key point. Sign convention (very important) For grid-connected inverters (including Sigenergy): Reactive Power Meaning Positive Q (+) Inverter is absorbing reactive power (inductive, lagging PF) Negative Q (−) Inverter is supplying reactive power (capacitive, leading PF) 👉 Your inverter is exporting capacitive reactive power to the grid. In plain English Your inverter is acting like a capacitor   - It is pushing reactive power into the grid   - This helps support grid voltage (lowering it when it is above 230-240V range)   - This is intentional behavior, not a fault. 3. Why is the inverter doing this? Modern grid-tied inverters (including Sigenergy) are required to provide grid support: Common reasons:   1. Volt-VAR control enabled      When voltage rises, inverter injects capacitive reactive power      This counteracts inductive loads on the grid    2. AS/NZS 4777.2 compliance       Australian standards require inverters to:          Adjust reactive power automatically          Support voltage stability    3. Local grid conditions       Light load, lots of solar nearby       Grid voltage drifting high → inverter responds 243 V is slightly on the high side, so exporting −1.7 kVAr makes sense. 4. Why is the power factor not close to 1? Because:    - You are exporting reactive power intentionally    - Reactive current increases total current    - PF drops even though nothing is “wrong” This is normal and expected for grid-support mode. 5. Is this bad? Should you worry? No.    - Residential customers are not billed for reactive power    - The inverter is operating correctly    - This actually helps the grid Unless:    - Your inverter is hitting current limits    - Or you see export clipping due to excessive VARs In normal operation, this is fine.