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planetming avatar image
planetming asked

Venus OS v3.30 – Peak shaving for ESS, Using Internal Grid metering

Hi, This is my first post.

I'm trying to Understand the Grid meter requirements for Venus OS v3.30 to enable the feature to limit system AC Export current.

My system in the UK is a MultiPlus-II 48/10000/140-100/100 the AC-IN is connected to grid, the whole house and grid tied PV is on AC-Out 1. I am running ESS and using the Inverter/Charger (internal) Grid meter. All is working fine. But we need to apply G100 Export limitation.

My Installer has just Installed OS v3.30. and upgraded ESS Assistant to 018C. We were expecting to see the new Peak shaving for ESS page with the settings to Limit system AC export current. But this page is not visible.

The Victron Blog
https://www.victronenergy.com/blog/2024/03/19/venus-os-v3-30-peak-shaving-for-ess/

states in the requirements "The feature works with all ESS supported energy meters."

Am I right in assuming then, that this feature only works when an external grid meter is connected and doesn't work with the internal grid meter?

Therefore unfortunately we will have to add more hardware to the system?

Thanks

ESSVenus OS
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2 Answers
nickdb avatar image
nickdb answered ·

Yip, requires an external EM.

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John Dent avatar image
John Dent answered ·

Could do with a bit more info from Victron on this.

The grid "feed in excess" can already be used to limit feed in (with or without EM). So, from the outside, the requirement to have an EM seems a bit arbitrary.

It's even more weird when you go looking at the VM-3P75CT. Guess what — it uses current clamps! So we go from the MP-II using either a built-in or external CT — which is, admittedly, a bit picky on wiring, but ultimately needs only two wires. But the "upgrade" is to use a EM which also uses CT, — which presumably not only has the same pickiness on extension wiring, but it also needs a power feed.

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planetming avatar image planetming commented ·
Hi John,

In my experience, the setting 'Grid feed-in>Limit system feed-in' does not do what it says. It only limits supported PV inverters (Fronius) or the Victron DC converters. It does not limit the main inverter output. I've tried this and it does nothing to the inverters overall output.

For example, say you set the Maximum feed-in to 1000W. If I then set the Grid Setpoint of the inverter to -5000W, then the inverter exports 5000W to the grid.



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nickdb avatar image nickdb ♦♦ planetming commented ·
You can set the inverter limit in ESS, that limits all DC to AC conversion.
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John Dent avatar image John Dent planetming commented ·
Yes. You're right. Set point overrides the grid feed-in.


Seems to be because the grid feed-in area is intended to be for feeding in excess PV.


I guess that leads to the question: will Dynamic ESS sell excess battery without a meter? (I've not tried it yet.) Given your finding, I'm thinking perhaps not.

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nickdb avatar image nickdb ♦♦ John Dent commented ·
It does.
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John Dent avatar image John Dent nickdb ♦♦ commented ·
As in 'it does lead to the question', or 'it does sell excess from battery without an EM'?


(I haven't tried it, as being in the UK on Octopus, so waiting on the "30 min slots" feature. And perhaps the "allow to upload own slot prices" feature.)

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