I have a Victron/Fronius zero-feed-in ESS system using high-cycle life AGM batteries. I want to use the top 20% for ESS and the bottom 80% in case of grid failure.
The batteries discharged to the set point (80%) and are basically staying there, despite there being plenty of excess solar capacity available, as well as the grid. Today it charged to 83%, but did this very slowly.
Why would it be discharging the battery, in the middle of the day, when there is plenty of solar available? Should it not be charging to 100% while it can?
In fact the ve.bus state has been absorption ever since I activated ESS, never bulk. It would seem that if there is tons of PV and grid power available, and it's roughly the middle of the day, it should be bulk charging.
The Fronius inverters were automatically detected and are being controlled well by ESS. Feed-In sometimes overshoots but is corrected in under a second or so when loads change.
The manual says this:
4.3.1 Mode Optimized (with BatteryLife) and Optimized (without BatteryLife) At times when there is excess PV power, the PV energy is stored in the battery. That stored energy is then used later, to power the loads at times when there is a shortage of PV power.
Maybe since it is limiting the Fronius' power for zero feed-in, it thinks there is no excess solar? is that possible?
Do I need to use charge windows to fix this?