Deye/Sunsync inverter - battery full, still drawing from grid

[Hedges]

Two strings oriented 90 degrees or 60 degrees to each other would help extend hours with more flat production.

Separate SCC as you mention. I've got Outback MX60, Midnight Classic 150, SMA/MSTE SIC40.

No experience with others mentioned on the forum.
Victron is popular and has wide range of PV voltage and output current, various prices.
Epever is an economy brand. Some had problems getting stuck in the wrong state, but others I think have been OK.
Renogy also may not be highly regarded, but cheap and readily available.
Some AIO may allow inverter to be switched off, saving power, and use as just SCC. Then you've got a backup inverter available.

 

[kolek]

Actually, I don't see why TOU settings are necessary for this use case, here's why:

On the battery screen, you set the battery shutdown voltage (or percentage) to, say, 10%

Then if the battery goes below 10%, inverter switches to grid and doesn't charge the battery, right?

Then when solar pushes the battery above the "restart" voltage, inverter switches back to running from battery.

That's all I need. Why do I need to mess with TOU?

I'm replying to my own message because I have the answer now and the solution might help someone else.
You DO need to activate TOU to run Deye in SBU mode, which is prioritizing in the following manner:
1. Most desirable is powering load from PV
2. Second most desirable is running load off battery
3. Least desirable is running off utility

The reason you need to activate TOU is if you don't, your inverter will just keep slowly drawing down your battery when there is not enough PV to offset your electrical demands, and eventually you can find yourself running into a low voltage state that could damage your batteries. Obviously your BMS should shut off your batteries before they reaches an excessively low state, but you want your inverter taking care of that process, not your BMS.