I’ve done more testing, and I’m almost certain that setting the “Battery Minimum Capacity” on my Growatt MOD 5000TL3-XH (BP) with the latest firmware has no effect. However, I managed to stop the discharging by using the Homey Modbus app and writing directly to the registers. There are two methods to stop discharging—both have quirks like @Phil_Bro above also experienced, but I’ll need to do more testing to confirm.
First method:
Set register 3067 to adjust the "On-grid Battery Discharge Stop SOC."
Interestingly, writing directly to this register doesn’t show up in the online settings (Growatt dashboard portal), but reading the register confirms that it’s correctly set. Also, if I change this setting online to a different value, I can read the updated value directly from Modbus.
Drawback:
When it’s set to the current capacity and discharging stops, the BMS/Battery goes into standby. Unfortunately, it doesn’t seem to wake up automatically when I change the setting back to 10%, but this could have been a fluke. I’ll need to test further to confirm.
I’ve also added a small JavaScript snippet to ensure the value stays between 10% and 99%, since setting it to 100% triggers a warning online
“Stop Charging SOC > Off-grid/On-grid Battery Discharging Stop SOC %”
—I’m not sure what it means, but I’ve decided to respect the warning.
Second method:
Set register 3036 to 0 (%), which adjusts the “Discharging Power Rate.”
This seems to be the best way to stop discharging. Like the first method, changing this setting doesn’t reflect in the online status, but reading Modbus confirms the value when it’s updated online.
Drawback:
While this stops the discharging, there’s still a small, almost negligible discharge.
The battery doesn’t go into standby and continues making that slight, audible whining noise. Not a big issue, and still a better outcome than not waking up from standby. But I still need to do more testing.
@Edwin_Biemond , do you think you can integrate these settings into the app?
- Register 3067: “On-grid Battery Discharge Stop SOC” (0-99 (=%))
- Register 3036: “Discharging Power Rate” (0-100 (=%)
Also, good news, @Gruijter has incorporated the app into the “Power by the hour” app to create better charge discharge scenes based on dynamic energy contracts 
Still have to investigate the possibilities though.
Cheers
