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eleusis avatar image
eleusis asked

Multiplus 2 15000va anti islanding

Im looking to buy:

Multiplus 2 150000 48v.

cerbo gx

24kw solar.

4 x 14.3kw battery banks

3 x 450/100 charge controllers

Victron EV charger

Location: Ireland

I dont want to ever feed into the grid. Instead just use the grid as back up (rarely as 15000va is enough) and to charge batteries and EV at night. I have a few questions please.

As I udnerstand its possible for multiplus 2 and quattro to back feed back to grid very small amounts. Id like to avoid this. I know I can set the set point up to limit this but id like to know what functions my system would have without using ESS mode.


1.) Can I have ESS mode off even though the AC in is connected to grid?

2.) When ESS mode is off does this stop the small amounts of back feed?

3.) Can I schedule charging of batteries from grid without ESS?

4.) Will the Victron EV charger still have capability to use excess solar without ESS?

5.) If I use an external antiislanding device such as the Ziehl UFR1001E, does this allow me to use ESS mode without feeding small amount back to the grid. Essentially does this block the small amount of back feed?

thank in advance for any info and help


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2 Answers
Alexandra avatar image
Alexandra answered ·

@Eleusis

The MP2 already has anti islanding built in. And no the external device does not help with that.

You can set your grid set point higher and that usually prevents the feedback. How high depends on reactive loads.

You can AC ignore during the day (usually accidental feedback is solar production related) and reconnect in the lower light conditions.

ESS is an assistant that mixes grid and solar. For loads. So if you don't program it you don't have it.

You can set your input current limit down to force solar to work for loads but it is easier to make the system work by disconnecting if you don't have ESS assistant.

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eleusis avatar image eleusis commented ·

Thanks for reply. I dont need to mix solar and grid for loads because I wont ever exceed the output of the inverter or battery capabilities. All I need it to do is in winter during specified night hours charge batteries and/or bypass to charge car. Will this still be possible without ESS.

Also with ESS turned off but AC in connected will backfeed be 100% off?

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Alexandra avatar image Alexandra ♦ eleusis commented ·
Yes it is possible.

You can use either node red or a generator assistant for that if you want it automatic.

There is a way to hook up the relays and use the generator start stop from the GX menu to connect and disconnect from grid too. If node red is not the way you want to go.

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h2009 avatar image
h2009 answered ·

Just do what I do.

Node red to open the relays so it's physically disconnected from the grid (other than off peak hours). I did test around with overload situations as well so in these events the grid would connect again (and disconnect when load is normalised) but its never occurred.


In my opinion you'll never stop grid bleeding either direction it was driving me mad so relay situation worked best for me.


Also I use DESS to control the charge times and predictive solar/loading.

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eleusis avatar image eleusis commented ·

This sounds promising.

In my opinion you'll never stop grid bleeding either direction it was driving me mad so relay situation worked best for me.

Not sure if your saying its not possible to ever stop beleeding or if you mean that using Node red solves it becuase ESS is off.


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nickdb avatar image nickdb ♦♦ eleusis commented ·
There always is an ebb and flow with power, that is normal and is affected by the loads you have.

This is not exporting or back-feeding.

That does not happen unless you enable it.

Yes, you can bias the system to always gently pull power from grid, or just open the AC IN relays based on a variety of logic and methods, which makes you off-grid effectively.

ESS has a lot of automatic capabilities which would make your life easier for scheduled charging, or using DESS to charge automatically on cheap, dynamic tariffs.

The system has the necessary compliance and certification for this purpose.


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h2009 avatar image h2009 eleusis commented ·
Sorry let me be more clear; bleeding will happen if you keep the relays closed (I.e connected to grid). I have tried as others suggested to put a positive number on the grid feed but all this does is keep drawing from the grid; but in some events it will push it back.

Using Node red to open/close the relays at set times will prevent all bleeding as it's physically disconnected.

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