Error connecting to adapter/inverter
Hi everyone
First time user here. I have a EW11a connected to my inverter and network. I have followed the instructions on Github for both Tony's and Nathan's addon.. I have also briefly tried Modscan 64
None of them connect, which obviously makes me doubt the connection between the inverter and EW11a.
Our solar was fitted 2 weeks ago, the installer has been doing it over 20 years and said he had put RS485 wiring in a number of times before. At the end of the install, 2 wires were left coming out of the KH10, labelled RS485 (it didn't say which was which). I plugged them into the EW11a, connected to it's local wifi before adding it to my router and network. It was given the address of 192.168.0.61 on our network

I can access the EW11a fine on 192.168.0.61 via the web browser
It has been running for a week and the Serial Port state seems to show traffic, as does the netp (it seems to have found the Home Assistant IP address (192.168.0.7):
Serial Port State
Received Bytes
14284942
Sent Bytes
417728
Failed Bytes
0
Config
9600,8,1,NONE
Received Frames
1796303
Sent Frames
52216
Failed Frames
0

Communication State - 'netp'
Received Bytes
626592
Sent Bytes
0
Failed Bytes
0
Protocol
TCP-SERVER
IP
192.168.0.7
Received Frames
52216
Sent Frames
0
Failed Frames
0
State
Connected

But FoxESS Modbus comes up with:
Error connecting to your adapter or inverter. Ensure the adapter is properly configured and is correctly wired to your inverter (see the setup link above), then try again. Details: Modbus Error: [Input/Output] Modbus Error: [Invalid Message] No response received, expected at least 8 bytes (0 received); No response received after 3 retries, continue with next request

and the other one just has no data in any of the fields.

I think I have done everything right on my side? local port is 502, inverter ID is 247 on the system and inverter.
I have tried swapping the 2 wires around that he left coming out and the received numbers go up a lot more slowly but FoxESS Modbus still comes up with the same issue (admittedly I haven't yet tried that since I installed TonyM1958).
Is my only option left to shut down the inverter and make sure the wires are connected? That is my last resort, just want to make sure there's nothing left to check first - I am sure he will have got it right, he knows more than I do!!
Fox Inverter Installation
1 x KH10 Hybird Inverter
1 x Fox ESS EP11 10.36kWh Battery
32 x JA Solar 435w across 2 arrays (13.92kWh)
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Site Admin
Re: Error connecting to adapter/inverter
I would pop open the com port and double check the pins that it's been connected to vs what the manual says.
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Re: Error connecting to adapter/inverter
To do that, do I need to shut it all down like I was sorting the cabling out from scratch?
I never really read that part of the instructions fully as that bit was meant to have been done for me
Fox Inverter Installation
1 x KH10 Hybird Inverter
1 x Fox ESS EP11 10.36kWh Battery
32 x JA Solar 435w across 2 arrays (13.92kWh)
User avatar
Site Admin
Re: Error connecting to adapter/inverter
I would turn if off yes as without a com port connected you'll see a meter fault.
Community Admin / FoxESS Elite Professional

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Fox ESS Tri Inverter Installation
2 x KH Hybird Inverters (Parallel Mode)
1 x H1 Gen1
24 x HV2600 (62.4kWh)
32 x 490w across 4 arrays
Dual Tesla Household
Heatpump & Low Carbon Housebuild
Re: Error connecting to adapter/inverter
Thanks
I'll have a look this week.
Fox Inverter Installation
1 x KH10 Hybird Inverter
1 x Fox ESS EP11 10.36kWh Battery
32 x JA Solar 435w across 2 arrays (13.92kWh)
Re: Error connecting to adapter/inverter
So, he had wired it up wrongly in the inverter! One wire was wrong. I've fixed that now and on the EP11 page, there's a lot more data being sent on the serial port and Netp (some were 0 before)
It now allows me to connect and setup FoxESS - Modbus
However, every entity shows Unavailable and Connection status shows a fault - changed to Error reading registers. Type: RegisterType.HOLDING; start: 36001; count: 3; slave: 247 from tcp://192.168.0.61:502: Exception Response(131, 3, IllegalAddress)

I've searched that error and it's been mentioned alongside needing a firmware update so I have messaged Fox to ask them to do that - let's see what happens next!
Fox Inverter Installation
1 x KH10 Hybird Inverter
1 x Fox ESS EP11 10.36kWh Battery
32 x JA Solar 435w across 2 arrays (13.92kWh)
Re: Error connecting to adapter/inverter
Vanginger wrote: Sat Jul 12, 2025 4:05 pm However, every entity shows Unavailable and Connection status shows a fault - changed to Error reading registers. Type: RegisterType.HOLDING; start: 36001; count: 3; slave: 247 from tcp://192.168.0.61:502: Exception Response(131, 3, IllegalAddress)

I've searched that error and it's been mentioned alongside needing a firmware update so I have messaged Fox to ask them to do that - let's see what happens next!
It could very well be the firmware but just to be sure can you confirm which inverter model it is, there is a known issue (and fix) with H3 Smart inverters
Re: Error connecting to adapter/inverter
KH10
Fox Inverter Installation
1 x KH10 Hybird Inverter
1 x Fox ESS EP11 10.36kWh Battery
32 x JA Solar 435w across 2 arrays (13.92kWh)
Re: Error connecting to adapter/inverter
Ok very likely firmware !, if it is Nathan’s integration you can try in HA going to Settings -> Devices & Services -> FoxESS - Modbus -> Configure -> Version settings and select the PRE133 version - that uses an older register map, but once your firmware is updated it will stop working and you would have to go through the config again and set it to latest.
Re: Error connecting to adapter/inverter
That worked! Loads of data now!
Thank you!
Hopefully Fox will update and I can flick the version back over..
I'll also update my signature so my system details are in there too.
Fox Inverter Installation
1 x KH10 Hybird Inverter
1 x Fox ESS EP11 10.36kWh Battery
32 x JA Solar 435w across 2 arrays (13.92kWh)
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