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markus32 avatar image
markus32 asked

Multiplus II: charge primarily with solar panels

I would like to connect a Multiplus II in series with the public network:

mp2.png

- The goal is to be as self-sufficient as possible and only draw power from the public grid if there is no other way.
- No feed-in to the public grid (-> zero feed-in)


From the videos I've seen so far the Multiplus II pulls energy from whatever energy source it can get a hold on; not good on a sunny morning when one full day of solar energy would easily be enough to fully charge the batteries.


Two questions: Can I configure the Multiplus II in such a way that it ...

(1) ... charges the batteries exclusively via the solar panels/MPPT? And only if I explicitly say so, charge the batteries via the public grid?


(2) ... only draws power from the public grid when the battery charge level falls below a critical value (let's say: 20%)?


Multiplus-II
mp2.png (143.2 KiB)
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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·
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klim8skeptic avatar image
klim8skeptic answered ·

Depending on how accurately you can set the battery monitor up in the multi, this might be easy.

Download Victron Connect. Open up your product in the demo section. Look at AC input Control.

ac-input-control.png



ac-input-control.png (160.7 KiB)
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offgridfren avatar image offgridfren commented ·
how can you see the multiplus from victronconnect? I have the multiplus connected with ve.bus but I can't find it
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klim8skeptic avatar image klim8skeptic ♦ offgridfren commented ·

You will need a MK3 interface.

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markus32 avatar image
markus32 answered ·

I installed the VictronConnect and tested the Demo mode. It seems the app is pretty limited; does the Multiplus II have more configuration options when using it with a Cerbo?

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JohnC avatar image
JohnC answered ·

Hi @Markus32

What you want is possible of course, and my own preference would be to set up Assistants in the Multi. Like with ESS, but using the 'Ignore AC' function to keep it simple. Full access to do this is commonly with VEConfigure software, over a MK3/usb dongle, or with a GX (Cerbo) via VRM portal. There's a bit of a learning curve to get there, and rather than us attempting a handfeeding essay, maybe best accessing the Victron website literature and/or the Search function here.

Your two questions.. 1/. Your 'explicit say so' needs defining. How would you want to do this, a little switch on the wall, a VRM selector, etc.? 2/. Using SOC needs a good a good source, and the Multi's own may be inadequate for this. So you may need a Victron shunt or a managed battery-provided value. Voltage and/or Load is easy, but SOC not quite.

So it all depends on what you have or are prepared to add. Sorry to sound blunt with this. An experienced installer could do all this in his sleep, but to diy it will need you to apply yourself. Please ask more though, that's part of it.



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markus32 avatar image
markus32 answered ·

I am still at the very beginning of my Victron journey :-D


1) What is this "VEConfigure"? By now I know "VictronConnect", which connects via Bluetooth to my Victron devices, and seems to be very simple.


2) Cerbo GX allows much more sophisticated configurations, yes?


3) Venus OS basically turns a Raspberry PI into a Cerbo GX, yes?


4) What is this "Victron ESS"? Is this an extra product? A plugin for Cerbo GX? ...


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JohnC avatar image JohnC ♦ commented ·
@Markus32

1) VEConfigure is software for configuring Multis and Quattros. I believe VConnect is slated to replace it, but it hasn't come that far yet. Bluetooth is usually for simpler systems, and if you really want to get into such kit, a Win laptop is probably the best way.

2) It's the hub for wired connections, once you step up from bt. Not always necessary for certain things, but once you have one you won't go back.

3) rPi doesn't have the port connections of the Cerbo, so requires adaptors for some things and even addons like usb hubs. Would you bother?

4) ESS is an Assistant (like a programmable thing) in the Multi that also requires a GX (Cerbo) to set up. For grid tied systems where export of power back to the grid is possible. To use it legally you may even need permission from your grid utility. Beginners don't start with this.

Ok now, I suggested you ask more, but all of this stuff is available via the Victron website. See the Downloads section for data sheets, manuals, technical articles and much more. And if you really want to delve, sign in to VictronProfessional and get full access to all the educational and other info the pros need.

I did say you'd need to 'apply yourself'. And I'd love to see you learn, but it'll get pretty tedious asking basics here. But I do wish you well..

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