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thomasw-1 avatar image

Open AC-input relais in ESS mode on MultiPlus-II

Is there a way to open the AC-input relais on MultiPlus-II by a command submitted to GX-device or with an input signal on MultiPlus-II when using ESS- instead of a virtual switch application? I would like to avoid placing an additional motor-switch or relais in between grid and MultiPlus device.

Thanks
Thomas

Multiplus-IIESSGeneratorvirtual switch
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Alexandra avatar image
Alexandra answered ·

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Hi Alexandra,

Thanks a lot for your detailed feedback.

Of course I studied the ESS manual and related features into almost every last detail. In general ESS offers some features (e.g. battery life), which are quite interesting features, which aren't available in other available assistants. However since ESS is not able to handle zero-feed-in and does not redirect Fronius-generated power properly into battery and after I did already balance the pros and cons of the Hub-2 assistant, I came to the conclusion that a forced grid separation would be currently the best approach.

The solution that you mentioned

  • seems also to be already outdated. It recommends to use Hub-2 assistant instead. Citation: "For systems with recent hardware, which has the new-type microprocessor (the 7 digit firmware numbers starts with 26 or 27, instead of 19 or 20) you could use the Self-consumption Hub-2 v3 assistant - however this is now depreciated."
  • seems only to control generator start and stop, but seems not to separate AC-IN relais during stop condition.
  • I am not really confident how the generator-assistant behaves, when connected to grid. E.g. I assume, that batteries would be also loaded by grid, instead by PV only.

Since

  1. Hub-2 assistant is already deprecated and not guaranteed, how it will be supported by future firmware releases (device- and GX-wise) and since
  2. there is no Victron provided solution for the current ESS weaknesses (zero-feed-in and battery loading by AC-out coupled Fronius) to be expected on near term,

I try to bypass these constraints with a forced grid separation that is controlled by a node-red implemented algorithm. Tests with a manual AC-In-fuse separation in relevant conditions have shown, that I can widely avoid such conditions and improve the weakness nearly to the actually expected behaviour.

In case I cannot control the MultiPlus-II integration relais externally, I will have to implement either an addtional motor switch or a suitable relais to AC-In.



Hello Thomas. I'm in the same boat. Did you solve that situation?

The problem I face is that after blackouts the system has to be power-cycled because it stops managing energy flow between ac-in and ac-out. I guess with a controlated isolation as you intended you also had to face that problem. How did it went for you?

https://community.victronenergy.com/questions/101812/ess-fails-after-a-blackout.html

Hi Sergio,

Since in Germany the conditions for power feedin changed, I migrated from a zero-feedin solution into a feedin based one.
Therefore this requirement got redundant for me.