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jacko avatar image
jacko asked

ESS, Fronius zero feed in and grid setpoint negative setpoint without draining batteries?

Hi I have an ESS system where ive incorporated a fronius primo 8.2kW inverter i have all communication set up and working for zero feed in, however i want to allow export of 16 amps or 3.68kW as this is acceptable, I assumed i would be able to set the gridpoint to -3600 and it would allow the inverter to put upto this amount out onto the grid before limiting output. However the victron actually started pulling power from the batteries to export 3600 watts to the grid. Is there a way around this as the customer can actually gain a tarriff from exported units but it makes no sense to drain the batteries into the grid.

Thanks Jack

ESSFronius
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rainerb avatar image rainerb commented ·

Hi,

as you have already recognised, the grid setpoint is not the appropriate value to reach your goal to limit the feed-in of your system.

The feature you are looking for is the "Limit system feed-in" (see screens of DayAndNight). As far as I know this feature is currently only available in Venus OS v2.60 Beta versions.

see also:

https://community.victronenergy.com/questions/47236/venus-os-v26014-available-for-testing.html


Regards

Rainer


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dayandnight avatar image
dayandnight answered ·

Hello @jacko,

I think that the sense of an ESS system is somehow different as you understand. For my understanding an ESS system is trying to use as much as possible energy of batteries to keep the balance and the bill to 0.

This is done by a gridpoint by 0 W or might be in the range of +/- 50W. The batteries are charged during day thru the PV system. When the batteries are fully charged and feed-in is allowed as you described the ESS systems feeds back all what is harvested with PV to the grid. You can control how deep your batteries are discharged during night or when only small power of PV is available with the Minimum SOC value.

For an optimum in sense of using own, "sun" energy the minimum SOC value is for example 10%. In case the idea behind the system is more a Backup system to have energy when there is no grid available the value should be much higher as 80% or 90%.

And you can control with the limit feed-in parameter to your desired amount how much is feed back.

According to my knowledge, you should set the grid set point between 50W | 0 | -50W and Limit system feed in parameter to 3600W. And when your batteries should be used only a little bit, I think you should raise the minimum SOC limit very high. Of course it is always some work and need time to find parameters which gives you the best result in what you want to get. And finally it is a balance between the system hardware and potential as well as with the selectable parameters.

I wish you success.

DayAndNight


feedin-limit-01.jpg (28.4 KiB)
minimum-soc-01.jpg (31.3 KiB)
grid-setpoint-01.jpg (27.2 KiB)
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laurentiupitran avatar image laurentiupitran commented ·

hello,

please, for your info, the amount of energy injected ON grid is different that what you think; attached graph is for yesterday - ESS system, three phase.

As soon exist ""in house""as load for ESS , loads that are switching even is pure resistive as iron press cloth or another as heating pump, you can observe that amount of energy injected is enuff big, even you set ZERO INJECTION in grid.

as i said many time before in another topics, i don t care too much during day time when is light outside, but this is not OK when energy injected on grid is from battery.

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jacko avatar image jacko commented ·

Thanks DayAndNight

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DayAndNight

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for such a great answer! Im with you all the way to where you mention the limit feed in parameter, I see from your screen shot its in a "Grid feed in" sub menu and it looks like the setting im trying to adjust but i cant find that sub menu. Ive checked through ESS and Inverter sub menu's but i cant find it. Can you let me know how to find it.


Thanks Jack

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jacko avatar image
jacko answered ·

Thank @DayAndNight im not sure what happened to reply above i tried to tag you but it seems to have glitched out. I understad everything you said and thanks for such agreat answer, It looks like the setting im looking for is the limit system feed in, but i cant find the setting from your screen shot it looks like its in its own sub menu "Grid feed in" but i cant find this sub menu on my ccgx. Any chance you can direct me to it?


Thanks Jack

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dayandnight avatar image dayandnight commented ·

Hello @jacko,

you will find in "Settings >> ESS "

Just one entry below the GRID SETPOINT

But attention! As @RainerB mentioned above ... "As far as I know this feature is currently only available in Venus OS v2.60 Beta versions. see also:
https://community.victronenergy.com/questions/47236/venus-os-v26014-available-for-testing.html"


... this menu entry might be only available in the release candidate 2.60 - I don't know earlier release version because I just started and I run an EM24 Ehternet which is only supported with this release candidate version´and I don't know earlier release versions.

But my setup runs perfect without problems and I am waiting to change firmware until 2.60 will be released!

DayAndNight






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grid-feedin-03.jpg (24.2 KiB)
grid-feedin-02.jpg (27.2 KiB)
grid-setpoint-01.jpg (27.2 KiB)
feedin-limit-01.jpg (28.4 KiB)
feedin-limit-01.jpg (28.4 KiB)
Ricardo Chavarria avatar image Ricardo Chavarria dayandnight commented ·
As far as I know, AC-Coupled should only be used if the PV-inverter is on the Output (AC-Out) of the Multi/Quattro, and it needs to follow the 1.0 Rule.


For me, that's why I had to get Grid-setpoint to -7600W (my PV inverter max), as I can't set the max export because my system is a grid-parallel system (PV inverter is on the AC-In side of the Multi).

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