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jyweet avatar image
jyweet asked

Is it possible to use three Multiplus II GX units in a three phase configuration?

I need to build a three phase system (ESS). Can I use three of the Multiplus II GX units, or is only one GX allowed and the other two MUST be only Multiplus II units? Can I not set the one GX unit as master and the other two GX units will operate with their GX disabled?

Multiplus-II
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marekp avatar image
marekp answered ·

You probably can, but where is economical sens of doing it this way?

MP-II GX is more expensive than plain MP-II

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jyweet avatar image jyweet commented ·

Thank you for the quick confirmation.

No it is not economical, other than immediate product availability, and the client looking for a solution a.s.a.p

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marekp avatar image marekp jyweet commented ·

Product availability can be a great motivator. :)

I can relate to that.

I am finishing my 3-phase system build on 2 MultiPlus-II and 1 EasySolar-II GX.

Did not plan to buy EasySolar-II GX but MultiPlus -II GX was not available. :)

Now I am trying to find application for MPPT 250/70 that came with EasySolar.

Probably will buy more solar panels.

In your case, you will probably have to physically disconnect those not needed GXs.

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jyweet avatar image jyweet marekp commented ·

Yes, what you say agrees with this:

https://community.victronenergy.com/questions/54262/use-more-than-one-gx-device-in-a-system.html

I just disconnected two of them now, and will see how the installation goes this week.


Thanks again for the confirmation.

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marekp avatar image marekp jyweet commented ·

With having 3 GX devices in 3-phase system I see one small problem.
When identifying units, during setup, with plain MP-II you can make them blink their LEDs so you know which one you are setting up.

When I tried this with my EasySolar-II GX I did not see any reaction to that command. Since I have only one GX device, there was no problem.

So, if I did not miss something, you have no easy way to identify them when you have all 3 GX devices.

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jyweet avatar image jyweet marekp commented ·

The setup worked fine, I just switched on the multiplus gx's one at a time and recorded the number assigned to each, then I know which one is which. The three phase setup was also fairly straight forward.


The problem I have now is with the L1 unit triggering an overload alarm in the morning under low load conditions when the unit need to switch back from utility to solar/battery power. Seems the energy from solar is not quite enough to supply all the loads when the switching happens.

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There can be another cause of “overload” shutdowns during low load conditions - see part 3 here - https://www.victronenergy.com/live/ve.bus:grid-codes-and-loss-of-mains-detection

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jyweet avatar image jyweet Guy Stewart (Victron Community Manager) ♦♦ commented ·

Hi Guy, I appreciate your time for responding here, and I also have to say thanks for your three-phase training video, it helped a lot.


The overload shutdown happened twice with low load conditions, and neither time it was related to a LOM condition (mains were live and well), and I am not too excited about the idea to disable the LOM detection. The firmware on all three units are 470.

Do I log a support request or do we continue the discussion in the community? I will also need the LOM grid code related password, I will contact my dealer an see how successful I am at obtaining such password.


Your assistance is much appreciated.

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Contacting your dealer from here is definitely the way to go.

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jyweet avatar image jyweet Guy Stewart (Victron Community Manager) ♦♦ commented ·

Hi Guy,

This issue has taken many turns and even more adjustments, but long story short, the client requested the removal of the MP II GX units from the premises since the problem persists, and it is clear that the product cannot deliver a simple UPS/loadshedding solution.

In your opinion, will a quattro deliver a more robust solution? The client has a quattro at his main residence and is very happy with the uninterrupted service he has there.

I am fairly disappointed in the product at this stage, since a simple low cost inverter would have been able to offer a more robust UPS/loadshedding solution. The entire idea of a UPS/loadshedding solution is to revert to inverting mode when there is a problem on the main supply.

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