System:
3xMultiRS single tracker (all connected to 3 arrays), no grid feed in
Not a sunny day but can get around 500-700w/h
6xPytes 48100R
DESS enabled
System behavior
DESS min SOC is set to 97% by Cerbo. Battery charged to 100%, BMS disabled charging. When this event happened, solar consumption dropped to 30w/h, all trackers in limited mode. Grid is used to consumers
Expected behavior
RS system continues to provide solar to consumption even if battery is charged. I understand it can be protective measures but in this case DESS should command to discharge battery to 95% or so to enable solar consumption
I’ve observed on my system (Multi RS 2 trackers) that the grid is used up until the SOC is with at least 5% above the set SOC.
In other words, if the min SOC is set to 30%, then it will use grid up until SOC is 35%, and only then the grid usage is dropped in favor of solar.
Between 30% and 35%, solar is used to only charge the batteries.
So try to set the min SOC to 94% and see if when hitting 100% the grid is still used.
You may need for this to work to bring the SOC below 90% in order for the logic to reset.
In case of 5% hysteresis (when we have discharged battery) it’s a proper behavior that prevent inverter jumping from grid-solar-grid-solar and energy is used (accumulated)
In my case it also proper behavior as inverters protecting batteries from overcharge that can happen if solar unexpectedly goes up and cannot be absorbed. The thing is that it’s valid if I have “keep batteries charged” turned on, but in my case I have dess. The goal of system is to use solar as much as possible, so I expect system, in case if BSM disable charging AND solar production is in limited mode, to start discharge batteries to have a room for further energy accumulation
From experiance and conversations - SOC higher 90% makes no sense for DESS to work properly. It is better to keep soc not higher than 90%. Usually 60-70% DESS SOC works best
Well, in order to read behavior I usually wait an hour , cause algorithm corrects itself once there is an edge case, like more sun, than predicted and higher SOC, than planned.
