Write Only registers

1502001Off-grid function SwitchU16N/A10:OFF
2502011Clear Off-grid Over-loading Protection FlagU16N/A1Write 1 to clear

Support tables

Equipment info

Inverter TypeThree Phase HybridSingle Phase HybridThree Phase Hybrid 25-50K
(10008 high bit)303132
Model Info
(10008 low bit)

Working modes

#Hybrid Inverter Working ModeHybrid Inverter Working ModeDescriptionNote
50000 high 8bits50000 low 8bits
111General Mode
22Economic Mode
33UPS Mode
42N/AOff Grid Mode
531EMS_ACCtrlModeValid Registers: 50202-50206
73EMS_BattCtrlModeValid Registers: 50207-50211

Fault registers

Fault CodeRegistersBITHEXDECFault Description
(Fault FLAG1)
BIT00x000000011Mains Lost
2BIT10x000000022Grid Voltage Fault
3BIT20x000000044Grid Frequency Fault
4BIT30x000000088DCI Fault
5BIT40x0000001016ISO Over Limitation
6BIT50x0000002032GFCI Fault
7BIT60x0000004064PV Over Voltage
8BIT70x00000080128Bus Voltage Fault
9BIT80x00000100256Inverter Over Temperature
(Fault FLAG2)
BIT10x000000022SPI Fault
35BIT20x000000044E2 Fault
36BIT30x000000088GFCI Device Fault
37BIT40x0000001016AC Transducer Fault
38BIT50x0000002032Relay Check Fail
39BIT60x0000004064Internal Fan Fault
40BIT70x00000080128External Fan Fault
(ARM Fault FLAG1)
BIT00x000000011SCI Fault
10002BIT10x000000022FLASH Fault
10003BIT20x000000044Meter Comm Fault

BMS Fault registers

RegistersBitsHexDecFault Description
(BMS Error Code)
BIT00x000000011Internal COM Fault
BIT10x000000022Voltage Sensor Fulat
BIT20x000000044Temperature Sensor Fault
BIT30x000000088Relay Fault
BIT40x0000001016Cells Damage Fault
(BMS Protection Code)
BIT00x000000011Cells Low Voltage Protection
BIT10x000000022Cells High Voltage Protection
BIT20x000000044Battery Module Discharge Low Voltage Protection
BIT30x000000088Battery Module Charge Over Voltage Protection
BIT40x0000001016Charge Low Temperature Protection
BIT50x0000002032Charge High Temperature Protection
BIT60x0000004064Discharge Low Temperature Protection
BIT70x00000080128Discharge High Temperature Protection
BIT80x00000100256Battery Module Charge Over-current Protection
BIT90x00000200512Battery Module Discharge Over-current Protection
BIT100x000004001024Battery Module Low Voltage Protection
BIT110x000008002048Battery Module Over Voltage Protection
BIT120x000010004096Power Terminal Over Temperature Protection
BIT130x000020008192Ambient Low Temperature Protection
BIT140x0000400016384Ambient High Temperature Protection
BIT150x0000800032768Leakage Current Protection
(BMS Alarm Code)
BIT00x000000011Cells Low Voltage Warning
BIT10x000000022Cells High Voltage Warning
BIT20x000000044Battery Module Discharge Low Voltage Warning
BIT30x000000088Battery Module Charge Over Voltage Warning
BIT40x0000001016Charge Low Temperature Warning
BIT50x0000002032Charge Over Temperature Warning
BIT60x0000004064Discharge Low Temperature Warning
BIT70x00000080128Discharge Over Temperature Warning
BIT80x00000100256Battery Module Charge Over-current Warning
BIT90x00000200512Battery Module Discharge Over Current Warning
BIT100x000004001024Battery Module Low Voltage Warning
BIT110x000008002048Battery Module Over Voltage Warning
BIT120x000010004096Power Terminal Over Temperature Warning
BIT130x000020008192Ambient Low Temperature Warning
BIT140x0000400016384Ambient Over Temperature Warning

BMS control

High 8 bits BMS Control StatusBit15Rsved
Bit11ForceCharge1: ForceCharge Command(ChargeCommand Bit10 must write 1)
0: Invalid(Null)
Bit10ChargeCommand1:Enable 0:Disable
Bit9Off-grid DischargeCommand1:Enable 0:Disable
Bit8On-grid DischargeCommand1:Enable 0:Disable
Low 8bits BMS Running StatusBit0~Bit70:Sleep 1:Charge 2:Discharge 3:Standby 4:Fault

Battery configuration

Battery Brand(52500)Protocol Configuration (52501)Note
2EMSN/AOnly for EMS
10Wattsonic Li-HVN/A

That’s all I have at the moment. I hope you will find it useful. The examples how I integrated the inverter into Loxone config using these parameters will follow in the next post.


  • Hey
    Thanks, great information, very helpful.
    I’m owning an M-Tec system (the same, just different badge) and I’m currently trying to decipher some of the values and there are two that confuse me, maybe you got some more experience and you can help.
    What is Invt_A_P (And B and C of course)? In total it’s always up to 100 W above the sum of PV power and battery power. PV power and battery power are matching the values in the official dashboard, so I do trust them, at least as far as you can trust companies and their dashboards. Might it be the inverter power including heat losses? The inverter has a big heat sink and it is still above 40 °C, so that might match. I’ wouldn’t be surprised at all if the company hides the system losses in its dashboard. What’s your experience, do you think that might be right?
    Second items isn’t that important, just confusing: Backup power is always something like 60 W, though the backup line isn’t even connected. I guess that’s a measurement error, probably tolerances on the current sensors, plus maybe something like a tolerance compensation to be sure to never get a measurement below the real value. Do you see something similar?
    Hm, while writing this, I begin to wonder if the things might be related, with the system pulling it’s own power demand from the backup line.


    • Hi Holger,
      Invt_A_P (And B and C of course) translates to Inverter_L1_Power, Inverter_L2_Power and Inverter_L3_Power in Germany and is simply the english naming convention for the three phases in use. It represents the AC output power of the inverter per phase and is not directly related to either PV power nor battery power.
      You don’t find these values on the overview page of the app or webpage, but you can see it under Devices -> realtime information in the “inverter AC parameters” block


  • Hi, thank you, this site helped a lot. I also wanted to connect via Modbus TCP, this worked for me at the end (i just used QModMaster):
    Slave-IP: IP of the Inverter (device “espressif” on the router)
    TCP-Port: 502
    Modbud Mode: TCP
    Unit ID: 255
    Read Holding Registers (0x03)
    Start Address: e.g. 33001 for the charging state (you must add 1 to the register number)

    This should word on Wattsonic inverters Gen3, M-Tec Gen3 and some other brands with the same inverter inside.

  • Hi,
    thanks for the Wattsonic template and documentation. I want to change the “Grid Injection Power Limit Setting” register value, it is read/write register. I have imported the Wattsonic template into Loxone Config, but the register is not listed in actuators only in sensors. I can read it but can not write into it.

    Am I missing something? Using wrong template version,…


    • OK, got it. The template does not contain all the read/write registers, but I can add them myself.

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