Note: the SoC min was finally set to the very low 5%, because at the end of feeding from the battery in the morning, the min SoC limit was not reached by far → remaining e.g. by 20% before
Note: The configured max. feed in power is limited to 6kW, to provide low and continous feeding in periods.
fixed price for selling/buying: the values chosen are to control the trading → first priority: providing the EEG (renewable energy community) with better selling prices and providing the community; secondly to the energy provider
DESS / charge/discharge limitation / usage of battery → prevent charging battery from grid was enabled (27-07-2026) → problem of charging from grid still happens, see below.
Your buy price isn’t changing, so cost wise, the sell price being high is irrelevant when buying from the grid. But that aside, l got a hunch that there might be a 2 hour offset bug somewhere in the scheduling in combination with the fixed pricing. It will take bit more time before I am fully sure of that.
My intension was to set the buying price high, to prevent buying during months with excessive solar.
I do have actually a fixed price for selling/buying.
In regard to buying, more accurately its like that, so called SNAP (Sommer Nieder Arbeits Preis): From April 1st to September 30th, it reduces the consumption-based grid usage fee (energy price) for household customers by 20 percent daily between 10:00 AM and 4:00 PM. The prerequisite is a smart meter with activated 15-minute interval metering (IME/Opt-In).
From this graph here, I would conclude (purple lines), that the scheduler still kept sending “discharge-targets” by the time your battery started to charge.
The targets then get corrected “up”, as your SOC raises rather than goes down, but still consecurive targets are “lower” than the Soc-line.
If DESS would have suddenly decided to charge again, the target-soc values would be ABOVE the actual soc-line.
So, I think “something else” (not DESS) is forcing your battery / inverters into charging.
You should review cell-voltages / battery voltages when this happens, if that drops unexpected low for the given Soc, emergency-mechanics to prevent deep-discharging may kick in.
Sorry but I can not fully follow your thoughts in this regard, maybe you can share some more details about the logic/strategy of the DESS!?
I guess the “Venus system - The set target SOC for this time slot” is THE setpoint for the charging/discharging to follow?
Nevertheless, I also thought there might be an issue with the ve configure settings, therefore I did some corrections :
Updated VE configure file via VRM (Date: 03.08.2026): mainly because for correction of
battery capacity from 330Ah to 1000Ah → before I thought 1/3 is needed, due to 3-phase system (3 multis)
changed the dynamic-cut-off voltage to lower and equal levels → to ensure no internal throttling or generate a warning (limit calculation in connection with battery capacity)
changed installed AC PV power (hoymiles micro HMT2250-6T), for the same reason as for the battery capacity; monitored via VM-3P75CT
installed a power meter at AC-IN (Date: 05.08.2026 approx. 16:30) via additional VM-3P75CT → in order to have a more accurate measurement of grid feeding/delivering because:
During midday, when I have enabled one phase of the electric heater for the water boiler “Heizstab” of 3kW via node red (actually via simple time window). There it have been shown/calculating in VRM “pulling from grid” even it was not a real power from grid. My suggestion was that there might be a mismatch due to conversion losses or accuracy of the measurements (multiplus, battery readings from terminals or battery bms itself,…) → wrong energy balance
to have a faster, more accurate feedback for better control of grid feed in or pulling
Some more data from today with that unexpeceted pulling from grid, please see the last two screenshots below:
