M-TEC Energy Butler
Monitors M-TEC Energy Butler battery and power metrics via Modbus
This template reads battery and power data from the M-TEC Energy Butler via Modbus TCP. It provides state of charge, voltage, current, temperature, BMS status, grid and PV power readings, and fault flags. Designed for Gen3 devices, it can be adapted for Gen2 with minor register changes.
- Protocol
- Modbus RTU
- Connection
- RS485, 9600 baud
- Registers
- 15, read only
- Brand
- M-TEC
- Key readings
- State of Charge (SOC) · Battery Voltage, Current, Temperature · BMS State, Error, Warning · AC Power Grid and Backup · PV Power and Power Meter · Fault FLAG1 and FLAG2
- Compatible models
- M-TEC Energy Butler
- Last updated
Registers (15)
15 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| State of Charge (SOC) | % | Read | |||
| Battery Voltage | V | Read | |||
| Battery Current | A | Read | |||
| Battery Temperatur | °C | Read | |||
| BMS State | Read | ||||
| BMS Error | Read | ||||
| BMS Warning | Read | ||||
| AC Power Grid | kW | Read | |||
| AC Power Backup | kW | Read | |||
| PV Power | kW | Read | |||
| Power Meter | kW | Read | |||
| Battery Power | kW | Read | |||
| Running State | Read | ||||
| Fault FLAG1 | Read | ||||
| Fault FLAG2 | Read |
Loading registers…
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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 battery state of charge and voltage trends on a live dashboard for residential energy storage customers.
- Create an alert when BMS error or warning flags are raised to enable fast remote troubleshooting.
- Track PV power production and grid power exchange over time to optimize self-consumption rates.
- Log fault FLAG1 and FLAG2 values historically to identify recurring issues in the M-TEC Energy Butler system.
- Compare battery temperature readings against ambient conditions to detect cooling or ventilation problems.
Installation
Connect the ModbusCloud gateway to the M-TEC Energy Butler's Multi-Funktion Port connector using the appropriate cabling.
Configure the Modbus communication settings on the gateway: 9600 baud, 1 stop bit, no parity, and auto timing.
Verify the Modbus TCP connection by reading a known register such as the state of charge (SOC) value.
Import the M-TEC Energy Butler template in the ModbusCloud platform and assign it to the connected gateway.
If using a Gen2 device, replace the register addresses in the template with the corresponding start registers from chapter 4 of the M-TEC documentation.
Confirm that all readings, including battery metrics, power values, and fault flags, appear correctly on the ModbusCloud dashboard.
Things to watch for
How do I know if my M-TEC Energy Butler is Gen2 or Gen3?
Refer to chapter 2 of the M-TEC Modbus documentation, which explains how to identify the hardware generation. The register addresses differ between Gen2 and Gen3 devices.
Why are some register values showing as zero or incorrect?
Some registers use int32 or uint32 data types that span two consecutive Modbus addresses. Verify that your register mapping accounts for both addresses and uses the correct byte order.
What baud rate and parity settings does the M-TEC Energy Butler require?
Set the baud rate to 9600, stop bits to 1, parity to none, and timing to auto. Incorrect settings will prevent communication.
Can I use this template for a Gen2 Energy Butler without modifications?
No. The template is designed for Gen3 devices. For Gen2, you must replace the register addresses with the corresponding start registers listed in chapter 4 of the M-TEC documentation.
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