H3-15-SMART Multiple ModBus Connection
Posted: Thu Nov 06, 2025 10:23 pm
Hi Everyone,
I’ve been using Home Assistant for quite some time, and after installing the H3-15-SMART inverter, I integrated it with the FoxESS Cloud. The integration works, but the available features are limited, and the 5-minute update interval is a bit slow.
While looking into a Modbus connection, I found that the installer has already used the RS485A and RS485B ports for the smart meter connection. From my research, it seems that RS485 supports daisy chaining multiple devices. Since I haven’t worked with Modbus before, I have a few questions:
1. Do installers normally use these same RS485 ports for the smart meter? According to my understanding, these are the EMS RS485 connections NOT the Meter RS485 connection to the smart meter?
2. If I daisy chain the smart meter and a Modbus device, is the setup as simple as Inverter → Smart Meter → Modbus device? How does the inverter distinguish between signals from each device? For example, if I want to set the battery self-use discharge SOC to 20% when tomorrow’s forecast is sunny, will the inverter handle that correctly?
3. What’s the most common Modbus device for this setup? I’m looking for a POE-powered device with no Wi-Fi.
I’ve searched the forum, but there isn’t much information specific to this inverter model.
Thanks in advance for any help.
I’ve been using Home Assistant for quite some time, and after installing the H3-15-SMART inverter, I integrated it with the FoxESS Cloud. The integration works, but the available features are limited, and the 5-minute update interval is a bit slow.
While looking into a Modbus connection, I found that the installer has already used the RS485A and RS485B ports for the smart meter connection. From my research, it seems that RS485 supports daisy chaining multiple devices. Since I haven’t worked with Modbus before, I have a few questions:
1. Do installers normally use these same RS485 ports for the smart meter? According to my understanding, these are the EMS RS485 connections NOT the Meter RS485 connection to the smart meter?
2. If I daisy chain the smart meter and a Modbus device, is the setup as simple as Inverter → Smart Meter → Modbus device? How does the inverter distinguish between signals from each device? For example, if I want to set the battery self-use discharge SOC to 20% when tomorrow’s forecast is sunny, will the inverter handle that correctly?
3. What’s the most common Modbus device for this setup? I’m looking for a POE-powered device with no Wi-Fi.
I’ve searched the forum, but there isn’t much information specific to this inverter model.
Thanks in advance for any help.