But tell me, your consumption forecast is still going well?
Yes, still looks reasonable!
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@dfaber right now, we have this strange situation again where PV excess is being fed into the grid in Green Mode instead of being used to charge the battery
Today’s PV production is very low, the target SOC reaches SOCmin towards the end of the evening:
It is even planned to draw current consumption from the grid:
This means that every kWh of PV surplus should definitely be charged into the battery instead of being fed into the grid. In reality, however, it is fed into the grid and the battery is even slightly discharged in addition:
The reason for this is probably that the current SOC is exactly at the current target SOC?
But that doesn’t make sense, in a situation like this, where the battery is even used up to SOCmin towards the evening, any PV surplus absolutely should go into the battery!
@dfaber don’t you see it that way? Shouldn’t the DESS algorithm be changed in this respect?
Currently, energy is charged into the grid, which should be available for consumption later…
VRM ID: b827eb273733
Of course, today it was only a very small amount of energy that was “lost” to the grid. That’s why I let DESS continue to run today. However, a few days ago in a situation like this, significantly more surplus energy was fed into the grid instead of the battery. That’s why I ended DESS at that time.
@dfaber the same again today: battery completely empty, not enough PV production for the rest of day to charge the battery sufficiently, yet all PV surplus is sold into the grid:
This absolutely must not be in Green Mode, isn’t that completely counterproductive?
…quick question:
Did you allow discharge to the grid in DESS settings?
When I do allow this, DESS proposes to discharge my battery completely to 10% SoC before the end of today 
When I disable this in the settings
…the planning looks more like “green”, with no discharge to grid.
My DESS system is not allowed to feed into the grid at all but I realised the same behaviour with v3.50~20. Switching back to v3.50~15 I did not recognise the issue anymore
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I experience the same problem. Sometimes unnecessary exporting to grid while I’m in green mode and disabled exporting. But I found the exact situation:
It happens at moments the predicted consumption is higher than the predicted solarpower (so the batterylevel is fixed set to a certain SOC%). If at that moment, there suddenly is more solar power than consumption: instead of charging the battery (increasing SOC%) which it should do, it seems to stick to the SOC% and chooses to export everything. It thinks it should keep its SOC% in both directions, but it should be allowed to increase.
Could this be verified? Does it make any sense?
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Yes, I can confirm that! Corresponds with my observations!
@dfaber what do you think?
Same issue on my installation.
DESS is feeding solar energy into the Grid, instead of charging the battery.
As a solution, I need to disable DESS, and set minimum Soc to current SOC, because when the sun is away, I do not want to discharge the battery when grid prices are low. I only want to charge from solar.
Is strange, as this was not the case some months ago. I think it indeed has to do when the predicted consumption is higher compared to predicted solar (as Pfuhu) is mentioning.
Dess is not workable in this configuration.
Thanks for cheking.
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I also observed this, especially when the target SoC was reached earlier than expected.
My current workaround is setting “Can you sell energy back to the grid?” to NO. This will charge the battery with excess PV power until it’s full and only then feed to the grid.
My system is 100% AC-coupled, i.e. no Victron MPPTs.
This seems to be the same issue.
Selling to the grid prohibited in settings.
Tomorrow is the day that battery is balancing, so loading from grid is fine. But some hours later most of the battery is sold back to the grid… (selling back to lower prices on top of that).
The whole battery to grid should not even be there.
Even in green mode and selling to grid is prohibited there seems to be some issue as dess seems to favor low soc by selling rather than retaining battery for loads.
Trant
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I already had the delivery back to the grid set to 0, but still does the same thing. Have now set it completely to ‘No’ and will see what happens.
Today same problem. Prediction for more consumption than solar power with consuption fed in from the grid (so SOC should not change). But finally less consumption and/or more solar than predicted: nothing went to the battery, everything was injected to the grid. ==> NOT OK
Thanks, this workaround works also for me.
For those who may not have noticed: this hack is a very good way of preventing unwanted charging of the PV surplus into the grid instead of into the battery in green mode:
Hello everyone,
I am french and new to the Victron ecosystem. I have installed my MPII GX with 7.2kwh of Pylontech battery one week ago ( Solar inverter on AC-input).
I have faced the solar-to-grid export instead of solar-to-battery issue like you all the week. I think I have found a workaround.
I have configured DESS like this :
- restriction for export to grid from batterie activated
- price for selling energy at 0€
- define low energy cost over night (22pm from 6 am) (0.15€/kwh)
- defin very high energy cost the day (from 6 am to 22pm) (0.75€/kwh)
- battery cost set to 0
For two days now, the behavior is correct. When high solar production is occuring everything goes to the battery (minus the load consumption of course). Yesterday, solar production was not enough so the battery have been charged upto 75% SOC during the night because today solar forcast is poor.
My understanding is that as selling energy to the grid is not rewarded and battery energy is at zero cost, feeding the battery is always the best trading solution.
This is for me the definition of green mode. Note that I do not have dynamic selling of buying price at all. So it suits me. I will let it run for a while to be sure but it is promising, I hope.
wait a few days until solar and consumption forecasts have been established
I know, there’s already a lot of feedback and observation regarding DESS selling to grid although battery is still not fully charged, sun is shining and every kWh is highly appreciated in rather bad weather conditions.
My observation on multiple days:
- It is related to the SOC and DESS SOC state. In my particular case here, target DESS SOC was set to about 50% and that was already reached in the morning.
- An unplanned high PV yield on a partly cloudy day leads to a grid sale as you can see in the graph between 8 and 10 in the morning
- DESS seems to adjust within those two hours, DESS SOC is now empty (11 PM) and every kWh solar yield is used to charge the battery
For me, it looks like DESS just reacts rather slow on a higher yield as expected. Maybe a simple priority rule as an addition to the forecast and SOC settings might help already:
In situations with unpredicted high PV yield, green mode and battery not charged: Charge the battery, do not sell to grid
Why don’t you use @dognose 's Hack?