question

klandos avatar image
klandos asked

Final check up of planned off grid installation

Hello,

I already have some experience with Victron in some RTV (dc only) and with an ongrid ESS installation with a multiplus II GX (on my recent house).

I would like to double check that the following will work:

Landhouse on Mallorca with no grid connection. We will live there all year long.

Planned System:

1x Cerbo GX

2x Multiplus II 48/5000

8x Pylontech 3,5kWh to start with

2x 250/100 MPPT for recharging

1x Generator with 3000 Watts

Some UTP Cables for connection Multiplus / Cerbo GX

2x VE Direct Cables for MPPT

1x BMS Type A cable for Cerbo/Pylontech wiring



1. Should I go with 2x 5000 MultiplusII or 1x 48/10000, especially regarding standby consumption. On top, if the 2x 5000 Multis are not enough I can add another one. This isn’t possible with the 48/1000, right?


Till now I have not configured a parallel system. But I have a MK3 / VE Configure. The house is single phase wired.

My other question is regarding the setup process itself for a parallel system.

2. When I first switch on the multis that are tied together on AC out, aren’t they unsynchronized and will explode? Or do they check if there is Voltage on the output and synchronize even if it is not configured?

3. Or can I just connect them on the DC side, update/configure parallel setup, shut everything down and after that made the final tie up on AC out?

Question about the Generator:

4. I would like to wire it just to an multis AC in as it only deliver continuous 3000 watt. Is that a problem when the second multi doesn’t have it on AC in?


5. Finally, the load:

Water comes from a well, the pump needs about 1kW when running.

Warm water from Solar + backup boiler.

Pool pump needs to run during (summer) day, another 600W.

Standby Consumption of the house should be around 100 W.

On top a kitchen, TV, Laptops, …

I will start with around 14kWp but can add more PV later if necessary.

Will the system fit or is it already to small? From my ongrid house I mostly never see more than 10kW, so I think it should fit.





multiplus in parallel
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3 Answers
Alexandra avatar image
Alexandra answered ·

@KLandos

I can tell by your questions you have no idea how to set up a parallel victron system. It would be best to get some training on victron professional first, read all the manuals, if that is the way you want to go.

But I can say from experience it is better to get a larger unit than try make two smaller ones work well together. There are many questions and complaints on this forums about current sharing and other problems with parallel. So keep it simple and size your battery bank correctly as well.

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klandos avatar image klandos commented ·
Thanks, so may should go with a 48/10000 quattro instead of a multiplusII to be flexible on extending Even if I dont need the extra AC Input?
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Alexandra avatar image Alexandra ♦ klandos commented ·
Yes It is easier for setup, especially for an inexperienced installer/user. The standby power of a quattro 10kva is smaller than 2x 5kva multis in parallel anyway.
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klandos avatar image klandos Alexandra ♦ commented ·
Are you really sure on that?

Zero load for a quattro seems to be 100Watt if I search the forum and „only“ 20 Watts per Multiplus.

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ejrossouw avatar image ejrossouw klandos commented ·

Did you know there is now a Multiplus-II 10kVA?

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klandos avatar image klandos ejrossouw commented ·
Yes, i know. But the manual says its Not able to be parallelised. If the 10k is a Bit too small I can‘t extend. If the 2 5000 are Not enough I can add a third one.



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

I think you should get a professional installer involved (and buy the components from him).

https://www.victronenergy.com/where-to-buy

As written in the community guidelines this is not really the place to ask about system designs.

https://community.victronenergy.com/questions/5889/new-victron-community-guidelines.html

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klandos avatar image klandos commented ·
Besides Design I think the question regarding standby consumption and config/install process is valid, isn‘t it?



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klandos avatar image
klandos answered ·

More or less everything is clear, except this points:

1. When I first switch on the multis that are tied together on AC out, aren’t they unsynchronized and will destroy each other because they are not in sync? Or do they check if there is Voltage on the output and synchronize even if it is not configured?

2. Should I just connect them on the DC side, update/configure parallel setup, shut everything down and after that made the final tie up on AC out? At the beginning only Earth / Neutral connected, leaving phase unconnected?

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