About the DESS category

Q&A and troubleshooting DESS
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This is a dedicated section for general DESS discussion - issues, requests etc.

Dynamic ESS on VRM

Dynamic ESS is live on VRM!

2024-05-07: Make sure to check https://community.victronenergy.com/articles/283506/dynamic-ess-green-mode.html too.

What is Dynamic ESS?

Dynamic ESS is an algorithm that aims to minimize the costs made on the grid and battery. It does this by taking several factors into account. First of all the energy price that, in case of a dynamic energy contract, changes every hour. Then it also looks at the solar and consumption forecast. Together with the grid limitations and battery costs and specifications it creates a schedule for the system that determines when to (dis)charge the battery.

Note that the system is not limited to dynamic contracts; it also works for systems that have a fixed pricing scheme.

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What do I need to use Dynamic ESS?

Dynamic ESS is only eligible for the installations which fits the following criteria:

  • Be an ESS;
  • Not use Generator connection outside of power outages;
  • Has 2-way communication enabled
  • Run Venus OS version 3.30 (or newer)

For best results:

  • Have a variable or dynamic energy contract.
  • Use a supported energy meter (especially if your system setup has heavy loads (EV charger, heat pumps) in front of the Victron system). See here for more information on this.

How can I configure it?

If your site has an ESS, the menu option to configure Dynamic ESS for your site will show. There is a configuration menu that you will need to fill out, before you can actually use it. While we tried to make it as easy as possible, you are likely to do some research in order to fill out all the questions. For instance, you will need to know your battery capacity and the amount of kilowatts it is capable of (dis)charging in an hour. But you will also need to know the formulas that build up the actual price that you pay for buying energy from and selling to the grid. These formulas are not the most straightforward thing to find as the info needed for it is usually somewhere in your energy providers contract.

We provide some example formulas in the dropdown, but that is no guarantee that it matches your actual contract. You need to check that yourself. The manual also gives some examples on how to take the step from your contract to the right formula.

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Known limitations

After this go-live, we will continuously improve Dynamic ESS.

Some of the things on our todo list:

  • Maximizing battery charge by the end of the day to cover consumption until sunrise
  • Periodically fully charge the battery to improve battery life
  • Adding support for varying service fees based on the time of day
  • Allowing users to enter a fixed schedule for grid-battery restrictions
  • Supporting fixed prices that change on the half-hour instead of the whole hour
  • Introducing (smart) support for high-consumption loads such as EV charging and heat pumps

More information

If you need more information, check out the manual. There has already been a lot of discussions on the beta implementation in the comments of five previous articles.

As always, we appreciate your feedback. Feel free to let us know how to improve, and thank you for being part of the development journey. To streamline communication, older posts are closed for comments, and any new feedback can be provided in this post.

When reporting a possible issue, please also mention your VRM URL or dashboard number.

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A post was split to a new topic: Can the electricity price curve be permanently displayed on the VRM/Dashboard

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@guystewart : link in post above is unfortunately not working - may you be so kind to correct it?

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In Portugal we can have Winter and Summer prices (based on the daylight saving time on Europe), on the image you can see the first area:

  • Summer:
    Monday to Friday
    Saturday
    Sunday

-Winter:
Monday to Friday
Saturday
Sunday

Darker orange is the lower price and lighter orange the higher price.

Is there a way to insert this schedule?

1 Like
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Hi,

I have a question about how to set up the following configuration:

When I sell the electricity I produce, I receive price X/kWh.
When I consume the electricity I produce directly, I receive price Y/kWh.

This means I get paid for consuming the electricity I produce.

How can I set this up in the DESS?

Thank you in advance.

1 Like
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My customer is setting up the Dynamic ESS but I can’t find definitive figures for the questions he raised, not seen them myself.
Charge
Dscharge
Cycles to 80% battery life?

System is 10kW Quattro + 6kW Fronius + 2 x 16kWh BYD LVS, It also has mppt rs with just 3.4kWp PV and 6.9kWp.on the Fronius. The Fronius is on the critical output.

Thanks for any help.

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Max charge
Max discharge

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Hello, how can I submit this forms. It still writes me, that Intervals can only end on a full or half hour, but the preset time is 23:59. How can I figure our? Thanks!

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Hi @ladama2004 ,

We took a look, but don’t see any issues with your schedule. Could you post the full price schedule you tried to configure?

With kind regards,

Jarco

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I’m having an issue the last few nights where my DESS is discharging my batteries at full rate, ignoring my grid limits and DESS settings for 30/40 mins on multiple occasions to discharge from grid. My grid limits are 11kw export and I’ve set the battery discharge limit to 7kw. And yet it’s exporting at 12-14kw… Any ideas

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Hi @JakeNorthern . The values you set in Dynamic ESS settings are capabilities, not hard limits, and are used by the system to calculate how much the system should (dis)charge within a timeslot.

Check here on how to configure that within Venus.

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Thanks for the response @Dirk-Jan Faber . Yes I am aware of that and have an export limit of 45A, 10kw. It still exceeds this.

Jake

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As far as I am aware I have set hard limits which it still exceeds

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For a 3-phase system, that 45A and 230V calculates into 17.93 kW, not 10 kW. The 10.35 is for a single-phase system.
In order to achieve 10 kW in a 3-phase 230V system, you would need to set the limit to approximately 25A.

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Yes it is a single phase system

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I need to consult with a colleague, but the quick fix for not exceeding the 10 kW limit would be to lower the set 45 A to 25 A.

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Yes but will that limit my solar export during the day? I’ve updated my cerbo to the latest beta firmware instead of stable and that has seem to fix it for now. But I would rather be using the stable version.

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We took a look at the data and we suspect this might be related to the installation itself. The system appears to feed more power into the grid than commanded, which is something that happens in parallel installations where the AC wiring has dissimilar impedance.

The control loop is working correctly and did attempt to limit power to 10kW. The hardware itself fed in more than that. This usually points to an installation problem.
You should be able to prove this without DESS. If you set the ESS grid setpoint to a negative value, you should see the same behaviour: It will feed in more than commanded.

Please see page 57 (section 6.7) in our white paper “Wiring unlimited” for an explanation.

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Ok that makes sense I’ll have to check this. I have non-victron controlled AC coupled solar on an et112 meter - will it take this into account with the export limit or will it ignore it. For for example if I set my export limit to 8,500, will it just try limit just the victron solar/battery export to 8,500, all the whole system export to 8,500?