DESS progrid selling excess PV ends up buying from grid also

For some strange reson my DESS decided today at 11:30 that it should selle excess PV to grid. Event selling price is 0,0019€/kwh (practically zero). And for doing so my system sold 3,4kwh and bought 1kwh from the grid. Selling gave me 0,02€ but buying cost me 0,07€ so this behaviour cost me 5 sents :slight_smile: (I have seen the same thing when kwh cost was 15 sents).
My system is in 3.60 version and i’m using “green mode”

Here is multiplus input (grid) and multiplus output (where load and pv is) graph


and here is info I save with help of nodered when dess_reactivestrategy change.

So I have two questions.

  1. why it decided to sell excess pv when price was zero
  2. why it bought from grid when it should not

I have also saved graph in nodered where I can see reactive strategy changes and also grid history with soc target history.

Today something similar happened.
DESS should sell 2 hours from 20:00 - 22:00 but at 21:00 it somehow for 15 minutes was in the reactive strategy “IDLE_MAINTAIN_TARGETSOC”


Here is “Reactive strategy” changes

and therefore it bought from grid (only a little but still)

and as 15 minutes it was not selling benefit was less than planned.

Hi,

In the case of ProGrid, this behaviour has been fixed in the most recent beta.

It will no longer enter idle [when target soc is reached early] but continue to support loads from the battery to avoid energy beeing bought back right after selling.

1 Like

There must be something else also, because target soc was 84 at 21 when just few minutes back it was 78.
It is bad to see but I,m recording target soc in nodered graph and it is seen where i made green circle.


It can also be seen in my prevoius post image when I record. Urrent values when reactive strategy changes.

I’ve send you a pn, dor your system id.
That “hop” indeed looks strange.

I’ll be oof tomorrow, but will look at this in detail.

One more strange thing DESS is planning.
Today evening 23:00 to 00:00 and tomorrow morning 00:00 to 01:00 battery sell to grid.
Price is -0,0048€ and -0,005€ per kwh.
I can’t understand this because my battery cost is 0,002€ per kWh so DESS is trying to make me negative profit :frowning:


Here it is seen that it thinks battery will be 100% but how the hell it thinks that selling with negative prices from battery is better than selling overflow from pv when battery will be full around 17:00?

will wait until 23:00 and see if he rethinks, but if not I have to turn DESS off…

Edit at 23:11
so at 23:00 it went to “pro grid” and SCHEDULED_MINIMUM_DISCHARGE (13) but there was nothing moving towards grid. I think it’s because target SOC and current soc difference is to little. at 23:15 it should set itself a lower target soc and then maybe?

edit at 23:20 target soc is 69% and soc is 72,6% and still the same reactive strategy but nothing is moving to grid. So strange that it is planning to but not doing according to plan.

Edit next morning
It seems that there was no planned selling to the grid (I assume because price was negative).
But DESS kept “pro grid” and SCHEDULED_MINIMUM_DISCHARGE (13) until 04:00