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svalvasori avatar image

Multiplus 12|3000|120 - Is a current transformer needed?

I see that the Multiplus II requires a current transformer to determine the grid power consumption, is this required for the Multiplus 12/3000/120? I don't see it mentioned anywhere.

MultiPlus Quattro Inverter Charger
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It depends on your planed setup. What do you want to do?

svalvasori avatar image svalvasori Matthias Lange - DE ♦ ·

I'll have a Multiplus, Cerbo GX, Smartshunt and MPPT. The intent is do be able to show grid power on Cerbo and also use Power Assist. It's documented on Multiplus II that the external CT is required for this, but I don't see any mention of a CT for Multiplus.

I've ordered the Multiplus, Cerbo and display - I would prefer to add a CT to the order if I need one, so would love it if someone with a Cerbo GX can tell me if they had to install an external CT for the Multiplus to report grid power and use Power Assist.

Thank you, but I still don't know the answer to my question. In the context of not having a CT, since there is no way to add one (and having no loads before the Multiplus), and that this is installed on a boat and I will not be putting power back into the grid.

1. Will I see power draw from the grid shown on the screen of the Cerbo?

2. Will Power Assist function?

I have to think Power Assist works on internal current measurement, or the feature could not exist with a stand alone Multiplus installation.


2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

The "old" MultiPlus don't have a connector for the current sensor.

As mvader mentioned it depends on how you want to install/use your system.

For ESS you should use a MultiPlus-II (internal anti-islanding-relay required in many countries by law!)

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The older multiplus (which is what I've ordered) is appropriate for a boat, even without the anti-islanding relay, correct?

Now, that we know that it is just a boat, we can answer your question.
(because of that my first question was about your setup and what you want to do)

You don't need the current sensor.
The Cerbo will get the information's about the grid from the Multi and will show it in upper left corner in the red box.
Also Power Assist because it doesn't need a current sensor.

svalvasori avatar image svalvasori Matthias Lange - DE ♦ ·

Perfect! Thank you. As a boater, sometimes I forget there is a world outside of boating :-)

mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi, you dont need that. Unless you plan on having loads “before” the inverter/charger.


The current sensor is for use (sometimes) in ESS systems, in houses. See our website.

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