FoxESS Community - Owners & Installers Forum

Hello all,

So please bear with me as I am brand new to Home Assistant, so my terminology may be all wrong and my thoughts completely ass-backward....and I am trying to do this without learning YAML and stuff.

Anyway. My system is 9KW of PV, a Fox KH7 inverter and 20kWh Fox batteries. I also have a Tesla Model Y and a Hypervolt Home 3 Pro charger - and am on Octopus Intelligent Go.

I have previously just been using schedules in my Hypervolt App and my Fox App to charge both the car and home batteries between 2330 and 0530 and it has worked well. However, I want to take advantage of any extra potential charging slots that Intelligent Go might give me over the windy winter months. So I have dived into the world of Home Assistant and bought myself a Raspberry Pi, an SSD and an RS485 to USB adaptor.

It's all up and running and I have installed integrations for Octopus, FoxESS Modbus and Hypervolt. Everything seems to work and I am able to see what is going on with all of these and do stuff like set work modes on the inverter.

So that takes me on to Automations. I want to do two things - probably the same as many others, and also the subject of various YouTube videos.

1) Prevent the house battery discharging into the car when IOG calls for the car to charge outside of the 2330-0530 slots.
2) Take advantage of any of these extra slots to top up the house battery, which will be very useful on grey but windy afternoons in the winter when there is pretty much zero PV production.

So. I watched a few videos and heard about the "Intelligent Dispatching" flags and writing automations that way. Then I saw another recent video that said not to use this anymore, but to use the "Off Peak" flags instead. So I think I have discovered how to set an automation to listen for "Off Peak On" (Off Peak Electricity (xxxxxx - not sure what the numbers here mean, but presumably my MPAN, Account number etc...) turned on) and to set the inverter to force charge at that point.

Then I presume that if I set another one to listen for the equivalent "Off Peak Off" signal and set the inverter back to Self Use at that point, it will just switch back to normal mode.

Of course, this depends on whether I understand this correctly - will Octopus send an "Off Peak On" and "Off Peak Off" signal at the beginning and end of every cheap rate period - dynamic or fixed?

If so, this seems a very simple way to accomplish my goals:

1) If Octopus intelligently schedules a cheap charge slot outside of the 2300-0530 period, it will send an "Off Peak On" signal and the car will charge and the battery will force charge as well - so no possibility of the battery discharging into the car. At the end of the slot, it will send an "Off Peak Off" signal, the car will stop charging and the inverter will go back to Self Use.

2) At 2230, Octopus will send the "Off Peak On" signal, my house battery will go into Force Charge mode and continue that way until the "Force Charge Off" signal appears at 0530 and then go into Self Use mode again.

To achieve this, I just have two automations - the first is just:

"WHEN --> "Off Peak Electricity (xxxxxx) turned on" THEN DO "Change Work Mode Option" --> "Force Charge"

And the second is just:

"WHEN --> "Off Peak Electricity (xxxxxxx) turned off" THEN DO "Change Work Mode Option" --> "Self Use"

Of course, I can't test this right now as there is no Off Peak going on at the moment. But....do any of the experts know if this approach will work?

Also - I presume that Octopus will only send the Off Peak signals if the car is plugged in and actually needs charging? If it's already full, then nothing happens as the car isn't asking for juice?

Thanks in advance!


Al

Well, to reply to my own post, it looks like that actually worked.

My car needed charging and Octopus scheduled a couple of cheap slots this evening. Looking at the Octopus "Off Peak" sensor flag, when it switched to ON (which corresponded with the smart schedule charging times in my Octopus app), the car charged, the inverter switched to force charge and the home battery charged too.

When it flipped back to OFF, the inverter switched to self use mode, the car stopped charging and all seemed to be fine.

HOWEVER - now the FoxESS Modbus integration seems to be getting no data and is showing everything as "Unavailable" in the dashboard. All still seems fine via Fox Cloud on my web browser or via the app.

Not sure what's going on on here and I can't see anything obvious with any of the RS485 wiring. So I have set the inverter to just charge from 2330 to 0530 as normal tonight and will try to figure it out tomorrow.

Maybe a failure of the RS485 to USB adaptor?

Well, I solved that problem. I bought another RS485 to USB adaptor - and got exactly the same behaviour. So I decided to check the cabling to see if there a break or a short or something.

When the installer wired it up, he left me a pice of CAT6 cable coming out of the inverter plug with two twisted pair for A+ and B-. I assumed that the white wire on each pair was grounded, so I wired one colour into A+ and the other into B- of the adaptor, and both white wires into the GND clamp.

Turns out that he had wired both conductors of each pair into the relevant inverter plug pin. So I fixed that and all is good. I am kind of surprised it worked at all in the first place....