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Modbus Force Charge from grid but not PV
Posted: Tue Sep 08, 2026 11:24 pm
by John1956
I know it's possible to set a Scheduled mode of Force Charge with PV disable but can this be done using Home Assistant and Modbus automation scripts?
Objective is to set the system (H1 hybrid) to do the above whenever the Octopus Agile rate is negative during the day.
i know PV is 'free' but when rates are -ve it means the grid has a surplus of generation so we should take from the grid to help it out.
Re: Modbus Force Charge from grid but not PV
Posted: Wed Sep 09, 2026 12:16 am
by MaterialBarracuda48
Your inverter is only 3.7kW, so not going to make much a difference if you use PV or disable it to your overall house load.
What I find with Agile though, is you struggle to find things to turn on to use a lot of power for a sustained period.
Dishwasher
EV Charger
Washing machine on hot wash
Tumble drier
Oven on with door open
Unless you have an EV charger, it is hard to pull 10kW or more for over an hour, you just run out of things to turn on.
It could just be me though, perhaps other have more luck during Agile's plunge periods.
Re: Modbus Force Charge from grid but not PV
Posted: Wed Sep 09, 2026 7:33 am
by John1956
Yes, you're right, it won't make much difference but it all helps and if it can be done with automation then at least I can have my biggest load running only from the grid when I'm away.
My household is multi-generational so there's double of all electrical appliances so I could easily hit 25kW albeit not sustainable for long.
Also programming has been a hobby of mine for 50yrs so building this solar system and controlling it with HA scripts has been an absolute joy (and a bit obsessive probably
)
Re: Modbus Force Charge from grid but not PV
Posted: Wed Sep 09, 2026 7:40 am
by John1956
AI suggest register address 11002 for PV power output control so I'll take a look that....
Re: Modbus Force Charge from grid but not PV
Posted: Wed Sep 09, 2026 10:14 am
by MaterialBarracuda48
Well if you have HA, and a lot of smart plugs/devices that can be turned on via this, then sure of course.
Regarding your register: First of all check if you can read in the value, next would be to create in the FoxCloud2.0 App a schedule as shown below with the PV toggle on. Read the register again when the schedule is active. Then enter the schedule, and toggle the PV switch off, and check the register address after saving the schedule.
So hopefully in testing, you will see the register change if AI has got the right one, and then you can create a quick test script to write the 'off' value and see if your PV output drops to zero.
Sorry if teaching you to suck eggs
