With recent updates, the previous issue (in v3.55) — where discharge power was limited during scheduled selling despite active load demand — now seems to be resolved. The system now adjusts discharge rates in real time according to load, which is a great improvement.
However, I’ve noticed that during a scheduled selling period (e.g. 1 hour with a 2 kWh sell target), the system stops discharging once the exact kWh target is reached, even if the time window is still active and loads are present on the AC output. As a result, the system goes idle and starts importing from the grid, despite sufficient battery capacity being available.
What I expected the system should be doing is to continue discharging to support local loads for the entire duration of the scheduled selling window, or at least until a defined minimum SOC is reached.
This is intended behaviour. When the target SOC of an hour is reached, the system goes idle. This ideally happens at the end of the schedule, just before the next schedule kicks in.
Reaching the target SOC to early causes longer idle periods. Depending on the pricing and expected consumption / solar, the system makes a decision what energy source to prefer during the idle period.
First thing you should do is to setup battery limits that match the actual system, as the current 3800 kW value doesn’t seem right. These numbers are used to make the schedule for the system and you can’t expect the system to produce a realistic schedule if the values don’t match the capabilities of the system.
We will add some more checking to make setting unrealistic values harder.
And how does this work when the consumption forecast is lower than the actual consumption?
In a dess environment it would be good to always supply power and not go to idle unless low soc limit is reached.
Of course some recharging could be done during low price hours when there is more consumption than expected and battery minium soc will be reached to early.
To prevent that, a dess minium soc margin could help. Where the margin would be added to minium soc level for prediction but there is margin when the consumption is higher so discharge can continue until the minimum soc level has reached to prevent expensive grid usage.
Thanks a lot for the detailed answers/ and explanation.
The values where indeed wrong and I immediately changed them.
First impression is that the system is behaving much better during selling periods, thank you for noticing!
Like @JeroenSt mentioned a second Minimal SOC Value where the system stops selling would still be nice. So the system is not always balancing on the MIN. Soc value.
Hi, I’m solving the same problem Cerbo GX + 3pcs MPII 5000 and MPPT250/100. I recently updated Cerbo GX from 3.55 to 3.60. Since then, the prediction of the battery SOC status has significantly worsened - it is significantly lower than reality. The standard is the prediction of reaching, for example, 50%SOC, even though it will then be possible to reach 100%. Subsequently, DESS sets the target battery status higher or lower than reality and exports energy at an unfavorable price or wants to recharge the battery from the grid (in the DESS settings I had to limit the max imported power to 0.1kW) = the battery is not charged, but the house’s consumption is purchased from the grid if it exceeds the solar gain, even though the battery status is well above the min. SOC, which is disadvantageous for me. The energy from the battery is later exported to the grid at a higher price, but this price usually does not reach the purchase price of energy.
I would welcome the already mentioned SOC reserve for DESS. e.g. adjustable value 0-20%SOC reserved SOC for house consumption. This set value would increase the min. SOC to which DESS discharges the battery. i.e. e.g. min. SOC set to 25% and reserve 10%=DESS would work with the battery up to 35%. It would solve unusual night consumption e.g. washing machine, dryer, irrigation pump, etc. Thank you.
