question

Leon Backbier avatar image
Leon Backbier asked

DESS Unexpected Behavior

Guys, I realy do not understand the behavior of DESS. Today an hour ago, it was selling Solar power at a low price with a SOC of 70% and an hour later it is charging the batteries with 5Kwh with high prices. How can i force DESS first to charge the batteries with free solar energy before selling it at a low price. Please help!!

dynamic ess
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4 Answers
daniel-feist avatar image
daniel-feist answered ·

It is beta functionality and the team working on it have been open about it's current limitations.

While initially there was some pushback when people were expecting it to be more dynamic (within the time slots) based on actual PV and consumption, the team do now recognize that this is a blocker and are working on this.

I thnk you just need to be patient and follow updates that are posted e.g. https://community.victronenergy.com/articles/256073/dynamic-ess-on-beta-vrm-part-4.html

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Dirk-Jan Faber (Victron Energy) avatar image
Dirk-Jan Faber (Victron Energy) answered ·

Looking at your site (assuming it has id `380851`), I don't see that it sold anything to the grid. Also it is charging right now, because the prices are at a price valley and the system is planning to use the battery for us when the peak happens (between 17:00 and 20:00).

If you don't want the system to sell to the grid, you can set the "Can you sell energy back to the grid?" to no.

What I also notice on your site is that you have it set to timezone "UTC", while you are located in the Netherlands. You can adjust that in the Remote Console by navigating to Date & Time.

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On closer look, the system did sell 0.1 kWh of energy between 12:55 and 13:00. Probably that was the moment that you looked.

This is something that might always happen. Some of the loads in your system got switched off around that time. The system needed to push the energy somewhere. Unexpected changes in the system need to be taken care of some way. And our default way (right now) is to either put the energy onto the grid or get it from the grid when needed. This will improve in the future, but even then I don't expect that always to succeed.

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Leon Backbier avatar image
Leon Backbier answered ·

Thanks Dirk-Jan, the utc time resolved some unexpected behavior. On the selling part I see that it is not using solar energy to charge.If you look further back you will see that the surplus is always feeded back to the grid. I guess i have to be patient and wait on the release. In my opinion, whenever there is a surplus on solar this should always go into the batteries instead of to the grid.

on the latest graph, this one is very handy reporting to the Tax in holland. Can i access this and select a larger period?


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With the DESS project I've learned to be a bit more careful when thinking of rules that need to apply always. If the sell price is high, a lot of users do want the system to feed back into the grid. For your wish, putting the "Can you sell energy back to the grid?" to no would work.

About the graph. You can find that via the dropdown on VRM.
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elvis avatar image
elvis answered ·

@Leon Backbier

This needs to be solved!!


It might have a chance at being solved if you put a correct title on this post.

With a bad attitude title that is essentially useless, its chances are VERY minimal.


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Justin Cook avatar image Justin Cook ♦♦ commented ·

Good point - I've modified the title to be at least a bit more representative of the apparent issue so perhaps the OP can get some additional feedback (though it looks like it may have been solved already).

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