How to limit grid power

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enfrafer asked Dec 5, '22

How to limit grid power

I am trying to limit the grid power in my new Victron ESS. According with my electricity supplier I can use a maximum power of 4.5 Kw. However, this morning I tried to charge my EV and I realized I was exceeding the 4.5 Kw so had to stop the charging...

My installation configuration is an Victron ESS + Fronius like this https://community.victronenergy.com/storage/attachments/13127-layout.png.

I have an EV charger brand "policharger" which has been working very well so far. In fact, the policharger reads the home instant energy consumption and adjust the EV charge not to exceed those 4.5 Kw (configurable data). This is not working anymore because the battery charge is not being considered by my charger (there is a kind of an amperimetric clamp reading the home energy consumption). I could obviously tried to measure the home + battery energy consumption however I wonder if there is not something straightforward to limit the energy from the grid in the Cerbo.

Thanks

cerbo gx grid

ev-charge-exceeding-grid-limit.png (120.7 KiB)

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Answer 1 · 2022-12-05T15:21:50Z

nickdb answered · Dec 05, 2022 at 03:21 PM

Uhm, under the inverter tab in the Cerbo, input current limit?

Lots of good stuff in the manuals if you choose to read them.

screenshot-2022-12-05-at-172027.png (58.1 KiB)

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johnone commented · Dec 05, 2022 at 04:02 PM

Aside from policing whether or not people have read the (often dogs-dinner like) manuals to your satisfaction @nickdb , is it the case there is a common misunderstanding here concerning inverting/charging and pass through, i.e. passing through from the grid given both the charging current and the AC loads? A few wise words from you on this might help many on here, including myself!

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nickdb ♦♦ johnone commented · Dec 05, 2022 at 05:39 PM

Hi, we’re trying to reduce the noise from members who haven’t first tried to help themselves, it does have a habit of chasing away other members. Its the old teach a man to fish philosophy, so I do bang on about it in the hopes that all the work that goes into educational resources is used.

But enough about that.

In this case the OP needs to limit grid usage (i have the same issue at home with a cheaper, lower rated supply).

So you need to cap grid usage.

For a fixed install just set it in the inverter and be done with it. In mobile/variable applications, then it makes better sense to set it via the gx (making sure remote override is set on the inverter).

An ESS by default will always pull from batts first (unless you’ve hit minima or are scheduled charging etc).

When you hit battery/inverter limits the system will top up from grid to the maximum of the set grid limit up to the rating of the transfer switch (defined in both the model name and spec sheet).

In this case there is also a PV inverter which is adding to the AC output.

The system is very flexible, and I get all the available info can be a tad daunting.

(Guys videos at professional.victronenergy.com are well worth watching when starting down this path, it helps us all have a common reference language and makes it so much easier to help).

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johnone nickdb ♦♦ commented · Dec 06, 2022 at 10:14 AM

Really interesting you're offering up a theory of learning. I hope you're open to the idea that, just like you have considerable expertise in one field, so there are people with considerable experience in another - such as how people learn. Not enough space here but safe to say that treating the manuals as 'educational resources', that 'noise from members' is because they haven't 'tried to help themselves' and that 'teach a man to fish' should be a guiding principle, are all propositions which could be worked on. For example, I'd hazard a guess that the manuals have much to answer for, much more than members who haven't tried. Hope that helps and if the manual makers are up for any kind of conversation then I'm willing.

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nickdb ♦♦ johnone commented · Dec 06, 2022 at 11:32 AM

It is actually a continuous work in progress. As issues are found, or ambiguities, we feed it back and docs are updated. There have been many small changes that probably go unnoticed.

You are welcome to create a topic if you find issues or have suggestions.

The dvcc section was recently reworked substantially to improve its usefulness.

Victron really do put a lot of work In behind the scenes to continually improve this site, the docs and to add video content.

The broad team is very open to comments from the community, if things can be improved there is a will to do so, technology limitations aside.

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enfrafer johnone commented · Dec 05, 2022 at 06:29 PM

Thanks a lot, seems to work quite well. As @Johnone mentions, maybe I was confused and did not want to limiting my full AC load, since my PV capacity is a bit higher than my grid limit (7.6 vs 4.5).

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img-9654.jpg (152.3 KiB)

Answer 2 · 2022-12-05T18:31:18Z

enfrafer answered · Dec 05, 2022 at 06:31 PM

Thanks a lot, seems to work quite well. As @Johnone mentions, maybe I was confused and did not want to limiting my full AC load, since my PV capacity is a bit higher than my grid limit (7.6 vs 4.5).

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