FoxESS FoxESS MQ2200 (grid) Modbus TCP template

FoxESS MQ2200 (grid)

The FoxESS MQ2200 is a hybrid all-in-one inverter with integrated battery storage, sold under several brand names including Avocado, ONE, and Avocado Pro. This Modbus TCP template reads grid-side meter data: active power at address 39168 (positive for export, negative for import), cumulative energy at 39625, and three-phase voltages and currents across phases A, B, and C. Connecting via the ModbusCloud Gateway over the built-in LAN or WLAN port on port 502 gives installers and facility managers a real-time, cloud-based view of grid interaction without relying on the FoxESS cloud.

Protocol
Modbus TCP
Connection
Ethernet, Modbus TCP
Registers
8, read only
Brand
FoxESS
Compatible models
Avocado · MQ2200 · ONE · Avocado Pro
Last updated

Registers (8)

8 read, 0 write

NameUnitAccessAddress (Hidden until you enter your email)Function (hidden)Type (hidden)
powerWRead
energyWhRead
voltages_aVRead
voltages_bVRead
voltages_cVRead
currents_aARead
currents_bARead
currents_cARead

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Use cases

  • Monitor grid active power in real time to detect unexpected import or export events on the FoxESS MQ2200.
  • Track cumulative grid energy to verify billing meter alignment and spot discrepancies between invoiced and measured consumption.
  • Alert on phase voltage imbalance across phases A, B, and C to identify wiring faults or grid disturbances early.
  • Compare per-phase currents over time to confirm balanced loading and flag asymmetric load distribution in three-phase installations.
  • Report weekly grid import and export totals for energy performance reporting across multiple FoxESS MQ2200 sites.

Installation

  1. Confirm the FoxESS MQ2200 is connected to your local network via its built-in LAN or WLAN interface, and verify Modbus TCP is active on port 502 by opening a telnet connection to that port from the same subnet.

  2. Connect the ModbusCloud Gateway to the same LAN segment as the inverter, ensuring it can reach the inverter's IP address; note the IP from your router's DHCP table as the MQ2200 obtains its address via DHCP.

  3. In the ModbusCloud portal, add the Gateway, create a new device, import the FoxESS MQ2200 (grid) template, and set the unit ID to 1 and the target IP to the inverter's DHCP address.

  4. Verify the connection by checking the live value for the power register (39168) in the portal dashboard; a non-zero signed integer confirms successful polling.

Things to watch for

All register values return zero or an error. What is wrong?

The MQ2200 exposes Modbus TCP on port 502 with unit ID 1. Confirm the inverter's LAN or WLAN interface is active, that no firewall blocks port 502, and that the Gateway is on the same subnet. A telnet to port 502 from a laptop on the same network confirms reachability before troubleshooting further.

The power register reads a large negative number unexpectedly.

Register 39168 is a signed int32. A negative value correctly indicates the inverter is drawing active power from the grid. This is expected behaviour during low-irradiance periods or battery discharge curtailment. If the magnitude seems wrong, check the gain factor documented in the FoxESS Modbus protocol: the raw value is in watts with a gain of 1.

Phase voltage registers A, B, or C show implausible values.

Registers 39123 to 39125 are signed int16 and report voltage with a gain of 10 per the FoxESS Modbus protocol document, meaning the raw integer must be divided by 10 to obtain volts. Confirm your polling client or the portal template applies this scaling; raw values without scaling will appear roughly ten times too high.

Register reads worked after installation but stopped after a firmware update.

FoxESS firmware updates can alter register maps. After any firmware update to the MQ2200, cross-check the active register addresses against the latest FoxESS Modbus Protocol PDF version. Re-import or refresh the template in your ModbusCloud portal if polling returns exception codes or all-zero responses following an update.

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