Tries to sell way too much energy to the grid, instead of just selling the excess energy at the end of the day, it wants to discharge till 50%, or maybe even less. (Not sure when it would stop, because i deactivated DESS when it reached 70%.
Tomorrow and the days after there won’t be much sun, but that doesn’t matter for green DESS looks like, it just wants to sell the energy in the battery.
Also, when it discharges to the grid for most of the hour, it stops discharging when it reaches it’s target percentage for that hour, and then starts using energy from the grid for the rest of the hour, instead of using battery energy. So it starts buying for the highest price for no reason. After the hour has finished, it starts the next selling session.
Why doesn’t it have a set point like, discharge to a certain percentage for some hours, after that is reached stop selling and start using battery energy again.
I don’t have that problem because I don’t sell electricity in principle. What I do know, however, is that the DESS only ever calculates for the time interval for which it has prices. The DESS also calculates the electricity requirement for this time interval. Everything that goes beyond that is sold. A similar phenomenon occurs when purchasing electricity. Even at exceptionally low prices, the system only buys as much electricity as it needs for the time interval (up to the point where prices are known). Here too, it would sometimes make sense to buy for the next 2-3 days. I don’t want to condone this behavior, but it is not a malfunction. It is based on the design of the DESS. Purely speculative, if the DESS followed a different logic. The opposite phenomenon could well occur. DESS would use the maximum storage capacity today and would miss out on lucrative sales opportunities today and would have to sell at cheaper prices tomorrow. Then some people would complain here too. The DESS does not speculate on tomorrow’s prices or PV production. The system always acts according to the facts that are fully available. Please don’t take this as a judgement, just an explanation of what is happening. I react to such situations that I predict myself by adjusting the Mind Soc in the VRM up or down.
Hello, i have also a problem with DESS green mode. I have enabled charge battery from grid, and still the battery was charged from the grid tonight. The battery was at that time 45%. Also the battery forecast is going to 20% , and today the forecast is a lot of sun. Now, after swiching off and back on DESS, the battery starts to charge. What did i do wrong here? Thanks!
Forecast is until 23u. (see screenshot above) I will try turning off battery balancing. But when balancing, i thought the battery will charges until 100% ? Thanks
I am using Victron DESS in green mode. I have tried official version v3.60 and am using beta v3.62 now.
I try to understand the behaviour of victron DESS but am not anymore.
I have 3pcs of Victron Multiplus II 5000/48 (threephase) with 110kwh battery capacity.
The batteries are being charged, but not at full rate (11kW) and instead, green energy is flowing back to the grid. At night when the battery is discharging to the grid but it is not discharging at full rate (15kW) and sometimes is buying from the grid while the battery has more than enough capacity left.
I set the SOC to 15% but most days the battery is not discharged to 15% in the morning but most of the time only up to 25-35%.
Between the dynamic buying and selling price I set a difference of only 2 cents.
Pleas check the image of yesterday. The battery had enough energy to last till morning. This morning the battery was only discharged to 36% (instead of 15%) but the inverters still took energy from the grid.
Can anyone advise how to get a maximum charge and discharge of the batteries without buying from the grid
I’m not sure (yet) how to implement this specific requirement but I am experimenting with a hybrid DESS setup where we keep VRM DESS as the ‘master scheduler’ (Green or Trade both possible) assisted by Node-RED DESS running in parallel (but not setting the actual schedules) to provide specific triggers to intervene in the VRM DESS behaviour.
For now my efforts are focussed on early day (before new prices roll in) buy opportunities to make better use of dynamic pricing on a trade only system (no solar), but as a concept this approach allows many other ways to influence DESS to suit your particular requirements.
What proved to be a valuable ‘hack’ is the ability to have the Node-RED scheduler running as Trade scheduler with a set upper SoC goal around dinner time and then use the resulting forecast data (with significant ‘buy’ bias in the morning) to trigger the VRM DESS ‘periodic full charge override’ (PFCO) feature on ánd off for a select few hours per day (possibly combined with a low price level requirement).
Even though this does not directly solve your requirement, the approach itself offers a lot of flexibility to nudge DESS to do what you want when you want it to.
