Marstek Venus D (pv)
The Marstek Venus D is an all-in-one balcony power plant with an integrated inverter, up to 4 kW of PV input across four independent MPPT channels, and modularly expandable LFP battery storage. This Modbus TCP template reads four PV channel power registers (power_a through power_d), giving your ModbusCloud portal per-MPPT visibility into solar harvest. Installers and building owners can track individual panel string output in real time, detect shading or soiling on specific channels, and feed the data into historical trend analysis without relying on the Marstek app.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 4, read only
- Brand
- Marstek
- Last updated
Registers (4)
4 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power_a | W | Read | |||
| power_b | W | Read | |||
| power_c | W | Read | |||
| power_d | W | Read |
Loading registers…
Send your device list
If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor each of the four PV channel power readings to verify balanced solar harvest across all MPPT inputs.
- Track power_a through power_d over time to detect capacity degradation or soiling on individual panel strings.
- Alert on a channel reporting zero output during daylight hours to identify a disconnected or faulted PV string.
- Compare daily energy contributions per channel to verify correct panel orientation and tilt after commissioning.
- Report per-MPPT power trends across multiple Marstek Venus D sites from a single ModbusCloud multi-site overview.
Installation
Enable Modbus TCP on the Marstek Venus D by navigating to the communication or network settings in the device app or web interface and activating the Modbus server on port 502.
Connect the Marstek Venus D to the same LAN segment as the ModbusCloud Gateway using a standard Ethernet cable, and confirm the device has a stable IP address.
In the ModbusCloud portal, add the ModbusCloud Gateway, import the Marstek Venus D (pv) template, and assign the correct unit ID and the device IP address.
Verify the connection by checking that power_a through power_d return live readings during daylight; zero values at night are expected and normal.
Things to watch for
All four power channels show zero even during daylight. What is wrong?
First confirm the Modbus TCP server is active on the device. Some firmware versions require Modbus to be explicitly enabled in the app settings. Also verify the device IP address and that port 502 is reachable from the Gateway's network segment. A firewall or VLAN separation between the Gateway and the device is a common cause.
One channel reads correctly but the others return errors. Why?
Register reads for addresses 30037 through 30040 should succeed in a single contiguous FC3 request. If one register fails, the device may be returning an exception for that address. Check that the firmware version supports all four addresses; older firmware revisions have been reported to respond differently to contiguous block reads.
Values appear but seem implausibly high or inconsistent. What should I check?
These registers are uint16 with no scaling factor defined in this template. If the raw value does not match expected PV output, cross-check against the Marstek app reading for the same channel. A polling interval that is too short (under two seconds) can cause the device Modbus stack to return stale or corrupted responses.
The gateway connects but drops readings intermittently. How do I stabilize it?
The Marstek Venus D Modbus TCP server can serve only one client connection at a time. If another system (such as a home automation platform) is simultaneously polling the same port 502, connection resets will occur. Use a Modbus proxy or dedicate the polling slot to the ModbusCloud Gateway to avoid conflicts.
Want to see how it works?
