RS485 Connections to Dual Inverters for Home Assistant

[DoingMyBit]

Hi All,

I've a recent install of solar + batteries. Due to the array size we are running dual inverters that should be running in parallel. My installer is coming back for a few snags shortly, and I'd like him to wire in the connections for RS485 to the inverters so that, if I choose at a later date to use Home Assistant, the wiring at that end is already done.

My question is, do the RS485 cable pairs need to wired into each inverter (ie. ending up with 2x RS485 connections to connect into later), or just the inverter set up as the Master?

Thanks!

PS. Sorry if the terminology is incorrect - I'm a newb!

[Will]

Hey,

So you'll want two cables (RS485A & RS485B) terminated into the correct pins (pin 3 & 4) on the coms port PER inverter. So if done correctly, you'll have a network cable coming from each inverters com port with two wires ready to be used in future.
You'll want to use a modbus to IP adapter per inverter not trying to daisy chain them.

See page 22 of the manual attached.

[DoingMyBit]

Thanks Will - super helpful!

[DoingMyBit]

Hi Will,

Thanks again for the advice regarding parallel inverters and RS485 above.

I've got the wiring done and sourced the 2x modbus adapters. I was just looking at the github readme for Nathan's integration and noted it said

"Assumptions/Dependencies
These may change as development progresses:
Only one FoxESS inverter is supported"

Do I need to do anything special here to get data and be able to push settings to both of the inverters?

Thanks!

[DoingMyBit]

Hi again, please ignore the bit about only a single inverter being supported - that is from Nathan's EM integration, not the Modbus integration - my bad!

I've progressed a bit, but getting an error on trying to connect to the integration. I suspect this is because the firmware on my inverters is up to date, and there has been an issue with mapping of entities thereafter. Is the only thing to do is wait for the integration to be updated?

Here's the error:

Error connecting to inverter (friendly name: "Master"). Error reading registers. Type: RegisterType.HOLDING; start: 31000; count: 55; slave: 247 from /dev/ttyUSB0: Exception Response(131, 3, IllegalAddress)