ESS system switches between changing and discharging when the house load combined with charging load is greater than the available PV power.
The system works perfectly with full sun.
I have a MultiPlus-II 48/3000/35-32, Energy Meter VM-3P75CT, the Multiplus is connected in parallel with a Fronius 5KW solar system.
ESS is set to charge batteries if solar is greater than the load (only charges with solar) grid set point is set to 100w.
The problem only happens while PV is less than the house load and charging load combined.
For example if there is no one home the standby load of the house is approximately 300w.
If the battery is @ 50% SOC and there is 4kw of PV the system will charge the battery with 1730 watts and works well.
If the battery is @ 50% SOC and there is 1.5kw of PV the system will charge the battery with 1730 watts and then switch to discharge because there is more load than PV.
After 2 seconds of not charging it will try and charge again, this continues switch between charge and discharge.
If I then limit the charge current to 500w the system behaves normally.
The issue only occurs while PV is less than the house and charging load combined.
The problem is that the Multiplus does not try to automatically limit the charge current to a value less than the available PV, How can I fix this?
Please see video for a demonstration of the problem.