Wattsonic Hybrid Inverter Gen3 Modbus RTU Protocol

In this post I will try to share the details about how to communicate with Wattsonic inverters using modbus protocol. Understanding the connection details and list of registers is very useful if you want to get live data from the inverter directly, not relying only on the cloud app. This is essential thing if you want to connect your solar inverter into any smarthome solution, which then allows you to properly balance the load, manage your energy consumption and export, and minimize the need to purchase additional energy from the grid. Also, there is the ability to control some of the functions of the inverter using that modbus connection.

In this (three page long) list below you will find groups of registers with the brief description. You won’t find this in the user manual. But, I strongly recommend to consult the user manual for additional details, especially to better understand inverter working modes and other settings, that might be available in the app and you will be able to read and also (in cases of RW registers) write into the device.

Now there is a warning. First, the Wattsonic Cloud App and its back-end hosted somewhere in Hong-Kong is not expecting that changes will be done via Modbus directly to the inverter. So in case you do write a change, that will not become instantly visible in the Wattsonic App. I spent quite a while investigating why the Operating modes do not change, until I went to see the inverter myself and saw that changes are happening and are just not propagating back to the cloud. So, some of the updates between cloud and the inverter are just one directional, but this is probably a small design flaw. Second, there could certainly be some inaccuracies in the lists below as well caused by multiple factors, so if you see that something has changed or does not work as described, it would be great to leave comment so that we can keep the tables up-to date. I am using it with 3rd generation of Wattsonic 3P 10K inverter. It could (potentially) work with other models, but I have not been testing it.

How to connect

I have connected the Wattsonic inverter with my Loxone smarthome using Loxone Modbus extension, which is extra piece of HW I had to purchase. But these settings below are applicable for any other master system of your choice.

Now, if you want to establish Modbus connection between Loxone Modbus extension and Wattsonic Hybrid inverter you need to know the following:

1. Wattsonic inverter uses Modbus RTU for communication with Loxone. Some people posted elsewhere that they use ModbusServer and Modbus over TCP, and in my opinion this was just a photo mock-up, completely misleading and wrong. So Loxone Modbus Extension is the right way to go. There might be other ways how to convert Modbus to TCP, but I have not tested this.
2. The wiring between Loxone Modbus extension and Wattsonic inverter needs to be done using separate twisted pair and it must be connected to PIN 13 and 14. [PIN 14 = A, PIN 13 = B]. It cannot be on the same bus with the SmartMeter (this was my initial mistake!).
3. The Modbus line settings are 9600 baud, No parity, Stop 1.
4. Not all values that come with the template from official Loxone library are being populated by live data. Try to use this updated template (below).
5. The terminating 120 Ohm resistor (supplied with the Loxone Modbus extension) is not needed in this case, the terminating resistor is already built-in to the Wattsonic Multi-function communication connector. You need to switch it on using small screwdriver (see detailed view).

Disclaimer

I take absolutely no responsibility for any damages you cause as a result of the use of any material shared on this site. It is for development purposes only.

You must accept that You and You alone are responsible for your safety and safety of others in any endeavor in which you engage. While the material on smarthome.exposed is provided in hopes that you build or tweak your own smarthome system, You are responsible for verifying its accuracy and applicability to your project. You are responsible for knowing your limitations of knowledge and experience. If you do any work with “main power” such as 240 or 400 VAC power wiring, you should consult a Licensed Electrician. Same applies for any high voltage circuits related to battery storage which I strongly recommend to not touch at all!

The following tables are showing the Modbus registers that can be used when communicating with Wattsonic Inverters. Please note that there might be some changes over time. This list was built for Third Generation of Wattsonic hybrid inverters. With any updates happening after that milestone some inaccuracy might be introduced. Use with caution.

So after the obligatory warnings, here are the lists of Modbus registers for 3rd gen. of Wattsonic hybrid inverters:

Read Only registers

ID	Register	Bytes	Description	Data Type	Unit	Accuracy	Note
1	10000	8	Inverter SN	STR	N/A	1	Read Bytes to string
	……
2	10008	1	Equipment Info	U16	N/A	1	Please refer to table Equipment info
3	10011	2	Firmware Version	U32	N/A	1	Read Bytes
	10012
4	10100	1	Date: Y/M	U16	N/A	1	Continuous read
5	10101	1	Time: D/H	U16	N/A	1
6	10102	1	Time: M/S	U16	N/A	1
7	10104	1	Grid Regulation	U16	N/A	1
8	10105	1	Inverter Running Status	U16	N/A	1	0:wait, wait for on-grid 1:check, self-check 2:On Grid 3:fault 4:flash, firmware update 5.Off Grid
9	10112	2	Fault FLAG1	U32	N/A	1	Please refer to table Fault registers
	10113
10	10114	2	Fault FLAG2	U32	N/A	1
	10115
11	10120	2	Fault FLAG3	U32	N/A	1
	10121
12	10994	2	Phase A Power on Meter	I32	kW	1000
	10995
13	10996	2	Phase B Power on Meter	I32	kW	1000
	10997
14	10998	2	Phase C Power on Meter	I32	kW	1000
	10999
15	11000	2	Total Power on Meter	I32	kW	1000
	11001
16	11002	2	Total Grid-Injection Energy on Meter	U32	kWh	100
	11003
17	11004	2	Total Purchasing Energy from Grid on Meter	U32	kWh	100
	11005
18	11006	1	Grid Lines A/B Voltage	U16	V	10
19	11007	1	Grid Lines B/C Voltage	U16	V	10
20	11008	1	Grid Lines C/A Voltage	U16	V	10
21	11009	1	Grid Phase A Voltage	U16	V	10
22	11010	1	Grid Phase A Current	U16	A	10
23	11011	1	Grid Phase B Voltage	U16	V	10
24	11012	1	Grid Phase B Current	U16	A	10
25	11013	1	Grid Phase C Voltage	U16	V	10
26	11014	1	Grid Phase C Current	U16	A	10
27	11015	1	Grid Frequency	U16	Hz	100
28	11016	2	P_AC	I32	kW	1000
	11017
29	11018	2	Total PV Generation on that day	U32	kWh	10
	11019
30	11020	2	Total PV Generation from Installation	U32	kWh	10
	11021
31	11022	2	Total PV Generation Time from Installation	U32	H	1
	11023
32	11028	2	PV Input Total Power	U32	kW	1000
	11029
33	11032	1	Temperature Sensor 1	I16	℃	10
34	11033	1	Temperature Sensor 2	I16	℃	10
35	11034	1	Temperature Sensor 3	I16	℃	10
36	11035	1	Temperature Sensor 4	I16	℃	10
37	11038	1	PV1 Voltage	U16	V	10
38	11039	1	PV1 Current	U16	A	10
39	11040	1	PV2 Voltage	U16	V	10
40	11041	1	PV2 Current	U16	A	10
41	11062	2	PV1 Input Power	U32	kW	1000
	11063
42	11064	2	PV2 Input Power	U32	kW	1000
	11065
43	18000	2	ARM Fault FLAG1	U32	N/A	1	Please refer to table Fault registers
	18001
44	30200	1	Backup_A_V	U16	V	10	AC Voltage
45	30201	1	Backup_A_I	U16	A	10	AC Current
46	30202	1	Backup_A_F	U16	Hz	100	Frequency
47	30204	2	Backup_A_P	I32	kW	1000	AC Active Power
	30205
48	30210	1	Backup_B_V	U16	V	10	AC Voltage
49	30211	1	Backup_B_I	U16	A	10	AC Current
50	30212	1	Backup_B_F	U16	Hz	100	Frequency
51	30214	2	Backup_B_P	I32	kW	1000	AC Active Power
	30215
52	30220	1	Backup_C_V	U16	V	10	AC Voltage
53	30221	1	Backup_C_I	U16	A	10	AC Current
54	30222	1	Backup_C_F	U16	Hz	100	Frequency
55	30224	2	Backup_C_P	I32	kW	1000	AC Active Power
	30225
56	30230	2	Total_Backup_P	I32	kW	1000	AC Active Power
	30231
57	30236	2	Invt_A_P	I32	kW	1000	Phase A Active Power
	30237
58	30242	2	Invt_B_P	I32	kW	1000	Phase B Active Power
	30243
59	30248	2	Invt_C_P	I32	kW	1000	Phase C Active Power
	30249
60	30254	1	Battery_V	U16	V	10	DC Voltage
61	30255	1	Battery_I	I16	A	10	DC Current
62	30256	1	Battery_Mode	U16	N/A	1	0:discharge;1:charge
63	30258	2	Battery_P	I32	kW	1000	Battery Power
	30259
64	31000	1	Grid Injection Energy on that day[Meter]	U16	kWh	10
65	31001	1	Grid Purchasing Energy on that day[Meter]	U16	kWh	10
66	31002	1	Backup Output Energy on that day	U16	kWh	10
67	31003	1	Battery Charge Energy on that day	U16	kWh	10
68	31004	1	Battery Discharge Energy on that day	U16	kWh	10
69	31005	1	PV Generation Energy on that day	U16	kWh	10
70	31006	1	Loading Energy on that day	U16	kWh	10
71	31008	1	Energy Purchased from Grid on that day	U16	kWh	10
72	31102	2	Total Energy injected to grid	U32	kWh	10
	31103
73	31104	2	Total Energy Purchased from Grid from Meter	U32	kWh	10
	31105
74	31106	2	Total Output Energy on backup port	U32	kWh	10
	31107
75	31108	2	Total Energy Charged to Battery	U32	kWh	10
	31109
76	31110	2	Total Energy Discharged from Battery	U32	kWh	10
	31111
77	31112	2	Total PV Generation	U32	kWh	10
	31113
78	31114	2	Total Loading Energy consumed at grid side	U32	kWh	10
	31115
79	31118	2	Total Energy Purchased from Grid at inverter side	U32	kWh	10
	31119
80	32000	1	Battery Types	U16	N/A	1
81	32001	1	Battery strings	U16	N/A	1
82	32002	1	Battery protocol	U16	N/A	1
83	32003	1	Software Version	U16	N/A	1
84	32004	1	Hardware Version	U16	N/A	1
85	32005	1	BMS Charge Imax	U16	A	10
86	32006	1	BMS Discharge Imax	U16	A	10
87	33000	1	SOC	U16	%	100
88	33001	1	SOH	U16	%	100
89	33002	1	BMS Status	U16	N/A	1
90	33003	1	BMS Pack Temperature	U16	℃	10
91	33008	1	Max Cell Temperature ID	U16	N/A	1
92	33009	1	Max Cell Temperature	U16	℃	10
93	33010	1	Min Cell Temperature ID	U16	N/A	1
94	33011	1	Min Cell Temperature	U16	℃	10
95	33012	1	Max Cell Voltage ID	U16	N/A	1
96	33013	1	Max Cell Voltage	U16	V	1000
97	33014	1	Min Cell Voltage ID	U16	N/A	1
98	33015	1	Min Cell Voltage	U16	V	1000
99	33016	2	BMS ERROR CODE	U32	N/A	1
	33017
100	33018	2	BMS WARN CODE	U32	N/A	1
	33019

Read-Write registers continue on the next page…