I got an AC coupled system installed about 3 weeks ago. Quatrro 8k, Fronius 8k, GX and BYD LVS Premium 24kwh. Grid is available between 0 and 6 hours a day, very random, and we could go 10 days with total grid outage. Configuration made by the installer is ESS with "keep batteries charged".
Things are running as expected, except that I am worried about two things that I think are related. High voltage alarm from BYD whenever it gets to 100% and the delta between cell min/max once the SoC is at 100%. Here's an example from today.
SoC reaching 100% at 9:11
Increase in min/max cell voltage, and the delta stays large as long as the batteries are not discharging:
And I also get the alarm (visible on the GX as well in the notifications):
Here's an example from yesterday showing the delta while SoC is 100% for a longer period. I reached 100% yesterday, through Grid in the early morning hours, then discharged a bit, then 100% again once the sun rose.
I don't mind sharing my exported config from vrm or any data that might help to understand what's happening. There are some days that I don't get the alarm, but the delta is always there. I read in different posts that this is normal for new installations, but I would assume after 3 weeks, I should be seeing some improvement?
I also read somewhere to keep the batteries at 100% for a week or so. Grid wise this is impossible. I could run a generator for that long but the cost would be very high.