In continuation of: V3.60: DESS grid setpoint:
I discovered that the grid setpoint is not working anymore in the final V3.60 release:
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.
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..
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. 
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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.
I am allowed to feed in.
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.
so I guess me tearing my hair out while on holidays is really because of updating software …
This is good news, been an issue for few updates now. Without negative minimal setpoint the whole system takes about 2-4 kWh of energy from grid for no reason. I will gladly sacrifice <0.5kwh of battery capacity at night to avoid it.
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When dess is disabled a negative grid setpoint does work
I updated my GX to v3.63, but still DESS is not respecting my negative grid-setpoint. I would rather feed to the grid from the battery, instead of taking consecutive gulps from the grid.
Where s the battery2grid restriction? Is it the “Can you sell energy back to the grid?” in the VRM DESS settings? - set to “Yes” in my settings.
@dognose, you noted that you updated the “responsible code”, when is the next release (or beta) scheduled?
It is queued to be released. Should be part of the next beta, unless that one is a mini-update with only a few critical changes.
Just check the changelogs, all DESS related changes will be prefixed with DESS.
Thanks for the note about the upcoming release! May I point out that the grid feed-in limit is also not beeing considered by the DESS calculations. I limit the battery-to-the-grid to about 3 kW, to be easy on the battery during such cycle phases. Whereas DESS is still considering it can discharge at 5 kW, the forecast is therfore quite off.
Hmm to answer that I would need to look into details. The Scheduler should only plan for a 3kW discharge, and additionally the local system will limit the requested rate to 3kW as well.
What the scheduler ofc. may plan anyway is discharging with 3kW and feeding in 2kW from solar, leading to a combined feedin of 5 kW.
May that be, what happened?
The scheduler plans more than 4 kW grid feed-in but then the set limit does not allow it. This means my 40 kWh battery is not discharged enough according to the plan, and then is already full at noon. An additional wish, is that a lower-limit, like 30%, can be set to avoid the grid feed-in to drain the battery, leaving some reserve.
See screenshot of today.
And this was the plan for today, I captured late yesterday night:
So, where did you set what kind of limit?
If you set a maximum battery discharge of 4kW in DESS, the scheduler should not create a discharge above that. (If that happens despite a set limit in DESS, I may forward this to the scheduler team to look at it)
If you want it to discharge more, then why you set a 4kW limit?
If you set local limitations, like the Inverterlimit or AC CURRENT limit, DESS is not aware of these.
My ESS has no “Limit inverter power” set.
Two menues below there are the “Grid feed-in” settings, with a “Maximum feed-in” limit set to 3200W:
Yet the DESS scheduler thinks it can discharge above that, but then does not - so the limit is enforced, yet the prognostic is way off.
Today another anoying problem is showing - with a nearly full battery, the DESS is drawing from the grid - fully unexpectedly (at 1AM where the heat-pump kicked in), and again at 7 PM, just before trhe plan to feed into the grid - which it is doing right now. This means I paid today 0,80€ without necesity. Most other days because of the disregarded “Grid setpoint” it is consuming around 0,4kWh from the grid. In a yearly total I will be paying over 40€ - which makes me decide to turn of DESS and wait for the VenusGX update with some fixes.
