FoxESS Community - Owners & Installers Forum

Just remember that this method is meant to be read only - to update editable registers, you still need the dedicated wifi modbus adapter. I was only interested in real time monitoring via HA , so this will do me nicely.

also gents,
fox updated my evo firmware last night - i can now write MaxSOC on grid via the inverter.
the only constraint is that mode scheduler must be disabled (have queried if there is a way for me to toggle that via modbus).
But for me - i was only using mode scheduler for forced charge overnight - now i can set the max SOC on grid, I can default to the older Force Charge periods. Happy days.

Managed to get a full control loop going now!
Checks solar forecast tomorrow - works out a reasonable Max SOC at 7pm and writes it to the register.
Force charge happens in the last 100minutes of the IOGo cheap rate overnight.
To handle IOGo intelligent dispatching, HA checks the dispatch windows, and if car is plugged in - if plugged in, moves zappi from eco+ to fast to enable charge. Limits the battery discharge current to a value that roughly allows only the house load to discharge - to avoid battery drain into the EV.

and created a nice dashboard for that too!

AdamNewberry wrote: ↑Wed Dec 17, 2025 7:41 pm I did manage to get a copy of the modbus document from Fox - can share with anyone if required.
i have to admit - im going beyond my capability if im honest.

Hi,

If you could share this, I'd be appreciative.

And thanks for putting in all the work you have with this, and sharing the detail. I'm just about to pull the trigger on a system with the EVO 10 and I'm very much planning to follow the route you have, using your work.
If you get the opportunity or have already taken any, could you share some images of the installation? I'm particularly interested in the modbus wiring and how you've plumbed the EW11 in. I'm a complete noob to and I've not managed to find any wiring information for the EVO 10, for this purpose.

Cheers,

Paul

Hi Paul,

see the attached.
i followed the wiring instructions exactly per the github page for the modbus integration.
I used an old usb cable to make the power and rs485 connections. to see how to wire the the rs485 to the data port on the inverter you have the pin diagram in the booklet that comes with the evo. if neded, I can take a photo of inside the connector on the weekend and share it.
to fix the EW11 to the outside of the inverter I used some velcro tape and its given power with the USB power adapter you see in the overview photo.

Best
Adam

Hi Adam,

Thank you for taking the time and effort to do this, it's very much appreciated.

I've read a little more around the subject since I posted and I understand it better now. I also managed to find pin out diagrams directly from Fox, for the EVO's COM port. I think my only 'issue' at this point is getting power to the EW11, as my battery will be around the back of the house nowhere near a power outlet. However, I can see that the RJ45 portion of the COM port has 12v (& GND) available, and there's also the USB port on the side of the case. As the EW11 only needs circa 200ma and 5-36v to power it, either of these may be a viable power source.

I have the installation penciled in for 9th Feb and I think I'll have a chat with the installing company before hand, to see what I can't use, as they may need it as part of the install.
And in the meantime, I can have a read of the Modbus document you've attached.

Thanks again,

Paul

Hi Paul,

Do you have any links to the wiring configuration? Just ordered the adaptor after having my EVO 10-8H installed on Monday. Any help/advice appreciated. Thanks

You could ask them to

youngsyp wrote: ↑Wed Jan 21, 2026 11:38 am Hi Adam,

Thank you for taking the time and effort to do this, it's very much appreciated.

I've read a little more around the subject since I posted and I understand it better now. I also managed to find pin out diagrams directly from Fox, for the EVO's COM port. I think my only 'issue' at this point is getting power to the EW11, as my battery will be around the back of the house nowhere near a power outlet. However, I can see that the RJ45 portion of the COM port has 12v (& GND) available, and there's also the USB port on the side of the case. As the EW11 only needs circa 200ma and 5-36v to power it, either of these may be a viable power source.

I have the installation penciled in for 9th Feb and I think I'll have a chat with the installing company before hand, to see what I can't use, as they may need it as part of the install.
And in the meantime, I can have a read of the Modbus document you've attached.

Thanks again,

Paul

You could ask the installer to wire up the modbus adapter for you. They will need most likely the usb port on the battery for commissioning but that’s a one off. I think it comes with a firmware they load in.

Hey Craig,

Please find attached.

I'm thinking of using some Cat6 ethernet cable and making my own flylead to connect to the 12v output in the RJ45 socket and the applicable RS485A/B pins of the COM plug. I've got these lying around as I tend to make my own ethernet cables and I think it will be neater than using the adaptor that comes with the EW11.

I spoke with my installer and they have experience with HA apparently so, I'm awaiting their suggestions.

Cheers,

Paul

I don't think that the battery usb port is a viable option for power as I don't think you would be able to put the cover on it - unless you have a right angle usb connector. The cover is similar to the one for the screen on the other side so its needed if outside.
If connecting to the Com port for data makes sense to connect for power as well if already there? Providing it has enough power?
I can't try it yet as I don't have any connection pins - anyone have any links to some that could buy? I also need to try carefully taking the glass cover off as well....

AdamNewberry wrote: ↑Fri Jan 23, 2026 1:25 pm You could ask them to

youngsyp wrote: ↑Wed Jan 21, 2026 11:38 am Hi Adam,

Thank you for taking the time and effort to do this, it's very much appreciated.

I've read a little more around the subject since I posted and I understand it better now. I also managed to find pin out diagrams directly from Fox, for the EVO's COM port. I think my only 'issue' at this point is getting power to the EW11, as my battery will be around the back of the house nowhere near a power outlet. However, I can see that the RJ45 portion of the COM port has 12v (& GND) available, and there's also the USB port on the side of the case. As the EW11 only needs circa 200ma and 5-36v to power it, either of these may be a viable power source.

I have the installation penciled in for 9th Feb and I think I'll have a chat with the installing company before hand, to see what I can't use, as they may need it as part of the install.
And in the meantime, I can have a read of the Modbus document you've attached.

Thanks again,

Paul

You could ask the installer to wire up the modbus adapter for you. They will need most likely the usb port on the battery for commissioning but that’s a one off. I think it comes with a firmware they load in.

Hi Adam,

I could but, where's the fun in that?

I mentioned above, I may make up a flylead. Then I could ask them to just plug in the RJ45 plug the COM port and wire up two leads split off from that cable into the respective RS485A/B pins of the COM plug. Nice and neat and then I won't have to upset the installation they've done into the COM port plug. And with an RJ45 plug on the other end, into the EW11, it'll be tidy.

Thanks for the tidbit on the commissioning and use of the USB port, useful information.

On a side note, I've been trying to come up with ways to negate the need for their CHINT too but, work has got in the way of that one.

Cheers,

Paul

Steveb198 wrote: ↑Fri Jan 23, 2026 1:37 pm I don't think that the battery usb port is a viable option for power as I don't think you would be able to put the cover on it - unless you have a right angle usb connector. The cover is similar to the one for the screen on the other side so its needed if outside.
If connecting to the Com port for data makes sense to connect for power as well if already there? Providing it has enough power?
I can't try it yet as I don't have any connection pins - anyone have any links to some that could buy? I also need to try carefully taking the glass cover off as well....

Useful context on the weatherproofing of the USB port, thanks,

As I don't have any of the USB components, if I decided to go that route, I'd need to buy them. So I'd buy a suitable plug or cable with suitable plug to butcher.

But I agree, the COM port does seem like the neatest way to go and I can't envisage it'll have issues providing suitable current capacity to power the EW11.
What would be the ultimate solution for neatness and convenience would be to understand what the 'Wifi_485A/B' pins give us. If it's the same connectivity and protocols as the '485A/B' pins...

Cheers,

Paul

AdamNewberry wrote: ↑Sun Jan 04, 2026 9:47 am Hi Brian,

all changes I made to the original modbus integration are here:
https://github.com/AdamNewberry/foxess_ ... /tree/main

i installed it via HA manually from my git fork download.

it went through all the normal setup steps like the official hacs version from nathan.

Adam

Are you planning to submit a PR back to the main project so others can benefit?

I think I've got as far as I can without having the Fox EVO to plug the EW11 into.

Knocked up a cable yesterday using an old Cat5e patch lead and have it wired to a 12v battery and powering the EW11 which arrived this morning. The EW11 doesn't follow the same pinout layout as the RJ45 ports on the Evo so, I needed to flip conductors 7 & 8, keeping the other end as it came from the factory.
Configured the EW as per this page: https://github.com/nathanmarlor/foxess_ ... Elfin-EW11

And now have a connectivity error when attempting to config the EW11 for Adam's integration.
Roll on 9th Feb.

Paul

Will wrote: ↑Fri Jan 23, 2026 2:15 pm

AdamNewberry wrote: ↑Sun Jan 04, 2026 9:47 am Hi Brian,

all changes I made to the original modbus integration are here:
https://github.com/AdamNewberry/foxess_ ... /tree/main

i installed it via HA manually from my git fork download.

it went through all the normal setup steps like the official hacs version from nathan.

Adam

Are you planning to submit a PR back to the main project so others can benefit?

Hi Will. Done since 3 weeks. Not sure if I need to do something to nudge it along. It’s sitting waiting for acknowledgment on Nathan’s side. Apologies but I’m no git expert. If someone could check the pull request and see if I’ve done something wrong, happy to amend.
https://github.com/nathanmarlor/foxess_modbus/pull/1007

I don't know if anything has been merged recently, the project seems to go through cycles of development then stasis for a while.

Will wrote: ↑Fri Jan 23, 2026 2:15 pm

AdamNewberry wrote: ↑Sun Jan 04, 2026 9:47 am Hi Brian,

all changes I made to the original modbus integration are here:
https://github.com/AdamNewberry/foxess_ ... /tree/main

i installed it via HA manually from my git fork download.

it went through all the normal setup steps like the official hacs version from nathan.

Adam

Are you planning to submit a PR back to the main project so others can benefit?

Hi,

My solar and battery system was due to be installed at the beginning of January, however due to the snow here in the north east of Scotland that week, the installation was delayed. I am hoping it will be finished next week. I will then try to connect it to my home assistant.

Brian