V3.60 grid setpoint not working

Q&A and troubleshooting DESS
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In continuation of: V3.60: DESS grid setpoint:

I discovered that the grid setpoint is not working anymore in the final V3.60 release:

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Damn that screen is dark, I can hardly read it.

Your battery is at 31%, which is on the low side - not sure if that could be related.
What’s the grid feed-in price and your battery cycle cost ?
Maybe DESS is deciding that it’s not financially worth it to discharge to the grid ?

My system is running at 150W grid setpoint and that’s working perfectly.
As stated in the other thread: that doesn’t necessarily exclude a possible bug with negative grid setpoint.

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I’ve been investigating this Issue these days.

The grid setpoint is always used, when DESS is running in regular ESS mode.

However, when DESS is placing a battery2grid restriction (either due to user configuration, or because DESS considers it suitable for the current schedule) the inverter additionally receives a discharge limitation as instructions.

That limitation generally matches consumption + dcsolar, so the inverter is basically allowed to fully feed in and drive loads.

During night - or on systems without dc solar - that limitation now equals consumption. That however means, the inverter cannot cover consumption AND feedin to the grid, because it’s discharge limitation only allows for consumption.

So, in a nutshell: When a bat2grid limitation is active, that basically takes precedence over a negative setpoint currently.

I’ve updated the responsible code to take this into account and - when a negative setpoint is an explicit user-request - set the maximum discharge power to a value of consumption + the amount required to sustain a negative setpoint despite any in-place bat2grid restriction.

We currently don’t have a schedule for the next beta, but the fix will be part of it.

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Sorry, my screen was in night mode..

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Fyi: I use the -10 watt setting because the victron measures 10 watt less than the smartmeter of the energy provider and because a little bit of feed in is cheaper than a littlebit of grid usage, although it is possible to less to notice. :face_with_raised_eyebrow:

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If you are not allowed to feed in from battery to grid by legislation it should not be possible to run a grid setpoint at minus when there is no solar available. So it’s a comprehensible behaviour.

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I am allowed to feed in.

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Yes, that’s the current idea. But there’s some things to consider:

  • Without DESS beeing enabled, the system has no idea of existing bat2grid restrictions
  • So, the User can turn DESS off, and set whatever setpoint he wants anyway.
  • DESS is using bat2grid restrictions also, when it matches desired behaviour, no matter if the user has a legal bat2grid restriction or not.

So, the bottom line would be:

  • Allowing a negative gsp would uniform the behaviour of DESS and ESS.
  • DESS will otherwise respect bat2grid restrictions and not actively “sell” to grid.
  • Users really facing a strict, legal bat2grid restriction simply should not choose a negative grid setpoint. Then, ESS will not cause bat2grid and DESS wouldn’t do either.
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Relocating categories since this is now production software.