Cannot connect

[brettjenkins]

Hi all,

Hope you all had a good Christmas!

I've recently had a Sigenergy system installed, with a 12kw inverter and 2x 10kw batteries. It's hardwired to my network, and I've assigned it ips via DHCP.

I asked the installer to turn on modbus which they did.

I can see that port 502 is open, but home assistant is unable to connect.

I raised a ticket with sigenergy who have confirmed that the settings are correct (they've provided the images below)

When the installer set it up initially, they said that when enabling modbus it asked for an ip, they couldn't apparently leave it blank. I wonder if this is my issue? Because that ip may limit what ips can connect to the system? But the problem I've read elsewhere is that when that ip is set, there's no way in the gui to unset it? Am I correct here? I've asked sigenergy to take a look but they just replied with those screenshots.

What am I missing?

[TypQxQ]

Network limitations maybe. Try restarting router, Sigen and HA.
/Andrei

[brettjenkins]

Silly question, but how do I reboot sigen?

[brettjenkins]

I've been doing some debugging - bearing in mind I know next to nothing about modbus.

So, with the help of claude, I've come up with this python script which i'm running in the home assistant container:

python3 << 'EOF'
from pymodbus.client import ModbusTcpClient

Try reading from the Plant device (ID 247) instead of inverter (ID 1)

client = ModbusTcpClient("10.50.0.13", port=502, timeout=3)
client.connect()
print("✅ Connected")

try:
# Try the plant register (30000) with device_id 247
result = client.read_input_registers(30000, count=2, device_id=247)
print(f"Plant register result: {result}")
if hasattr(result, 'registers'):
print(f"✅ Plant data: {result.registers}")
except Exception as e:
print(f"❌ Plant read error: {e}")

client.close()
EOF

when ran, it returns this:
✅ Connected
❌ Plant read error: [Errno 104] Connection reset by peer

it seems that I can connect to it, but when I try to do anything with it, the connection drops

I downloaded 'Modbus Monitor' for android, and i can connect to it, but when I send it a request to read a register, it returns with a blank response by the looks of it.

So, how do I fix this? Is this something that happens when the inverter needs rebooting? How do I reboot it? Is this something that happens if an IP was entered by the installer when trying to turn on modbus (which I think my installer did) - I honestly don't know what is and isn't to be expected here.

[discipleofnagash]

Following as I'm having the same issue and can't figure it out....

[brettjenkins]

Still awaiting sig support to get back to my new ticket. Will update when they get back to me

[TypQxQ]

Are you on the same subnet?
Try another router.

[brettjenkins]

I'm not, I'm on another subnet, the sigen is on a dedicated iot subnet, but I'm using pfsense and there are no restrictions between subnets, so that shouldn't be an issue.

I can't do anymore testing for now though because sigen support have helpfully turned off modbus support when I asked them to check the settings to make sure there's no ip set restricting it, so I've had to raise another ticket for them to turn it back on.

Their support seems rather useless

[TypQxQ]

LOL 🤣 , I've seen worse....

[hobbymachinist]

Ever since I got my inverter replaced due to some recall, the integration has been problematic. Initially the installer had setup the modbus configuration as host, the integration started working again once they changed it back to slave. After a week, it suddenly stopped working tonight. I suspect someone or something has turned off the modbus integration again.

I'm pretty cranky that they don't let customers directly control this setting and having to rely on the installer or sigenergy support for this. I wish they exposed this setting on the app for customers.

I have to wait till tomorrow to call the installer again and ask them to check the configuration. My time of day charging and discharging relies on automation through HA, and whenever the modbus integration stops working like this I have to step in and manually do it from the app :(

[hobbymachinist]

lolsob, I just created a support ticket. Let's hope I don't have to do it 3 times like you had to 😅

Thanks again for the update, glad you got yours working.

[hobbymachinist]

My installer toggled the modbus tcp server setting and that fixed it. So whatever update Sigenergy pushed disabled it even though the setting said it was enabled and they'd also removed the solar generation sensor which the installer had to setup again. Hopefully nothing changes from here on 🤞

[billflyboy]

Good to hear ! I asked my installer to do the same, will let you know if it works

[hobbymachinist]

This is what I got back from Sigenergy support team

[billflyboy]

Funny, I was about to post, I got exactly the same feedback and it seems back in order now !