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serimi89 avatar image
serimi89 asked

Multiplus II 48/5000 optimise loads from three different houses

Dear community members,

this might be a bit of a weird set-up or maybe I am just overcomplicating things. Anyway, thats why I am here, to ask for your opinion.

Let me quickly walk you through what I have planned (to be installed this winter): I have three holiday houses that are all physically connected to each other and have three separate power grid connections, each of them with their own earth rod, PEN bridge and meter. All three houses are used during summer period with some high consumers (Air Condition / Pools + Heating) and only one house is used in winter (I live there myself) with mainly lights / computers / kitchen / some Air Condition heating.

I would like to install a 5.4kWp system with a Multiplus II 48/5000 and a 10-15 kWh LiFePo4 battery which can fulfil my requirements for summer and for winter.


screenshot-2023-09-10-at-231045.png


Each house has its independent basic loads such as lights / kitchen (occasional use only) / outlets / pool (if applicable), however there are some other loads that are somewhat distributed. The two Air Conditioning outdoor units are connected to House 1 and 2 while the common Water Heater is connected to House 3.

In summer, I would like to run these high consumption loads as much as possible on solar / battery. Since the Multiplus is being fed by the AC-In of House 1 which can not handle all loads including its own basic loads (kitchen, lights, outlets), I need to design a system with automatic transfer switches in order to change the power source of each of the consumers to its original grid / house in case there is not enough battery / solar power available or the inverter fails.


Do you guys think this is the most viable solution? Is there something I am missing?

I am happy to receive your feedback,

Sebastian

Update:

Since people misunderstand my question: I am NOT trying to combine three grid connections into one. I am trying to simply switch consumers back to their grid connection in case solar/battery power is not sufficient.

I am simply interested in understanding if there is any other system design on the

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3 Answers
mvas avatar image
mvas answered ·

You need to consult with a local electrician ... Does your local electrical code allow AC power from home #1 to feed into home #2 or #3 when the Main 32 amp Breaker of Home #2 or Home #3 is OPEN?

Nobody on this forum is authorized to approve your wiring diagram.

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serimi89 avatar image serimi89 commented ·

thanks for your reply.

to clarify, the AC power will not feed into the entire distribution, but rather its being fed into one specific load with its own RCD. So a device is connected with P/N/E to House 3 and can be changed by switching P/N/E to House 1 + Inverter.

I am not asking for approval for the wiring diagram, I will go through this ultimately with my electrician.

My point is rather if there is a different system design concerning the victron side of things that would make more sense, that I dont know of (have done only off grid so far).

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mjs500 avatar image
mjs500 answered ·

If House AC supply in Greece are arranged as same uk 3 phase supply is run in to the street and each House is tap into 3 phase i.e. home 1 brown to neutral - home 2 black to neutral and home 3 is gray to neutral and so on so between House 400 v can be frond- street and roads feed from one transformer stepping down 11kv to 400v 3 ph

House feed with interveinal transformer on power pole is diffract as 400v 3ph is feed primary on transformer and 230v secondary to House and earthing in both cace so that fault current can operate protection device , fuse - mcb - rcd

But saying this You need to consult with DNO and local electrician in Greece

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serimi89 avatar image serimi89 commented ·

thanks for this, however I am NOT trying to combine the entire distribution or three grid connections to one! I simply want to switch a consumer (including all three connections: L/N/E) with its dedicated RCD from one house to another, with a transfer switch / changeover switch. At no time will the houses be electrically connected.

And again, I am looking for advice more on the Victron side, wondering if there is a more elegant solution to achieve the perfect load distribution.

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lifeingalicia avatar image
lifeingalicia answered ·

Ok I have three houses connect on 1 feed ! max 32A. I use Openhab and sonoffs o Tapos to control this, but I do run my own lines (not entirely legal) and I have a common WiFi via extenders.

Here in Spain if you have "neighbor" connections on the same transformer you can share feed in. E.G. feed in house 1 and use house 2 or 3. Same in Germany although the paperwork there is ridiculous. Worth checking.

This could be interesting as you could install PV on each house and control the excess.

Just house 1 would have blackout capability.

I use Openhab but Nodered is capable to this as well or some othe automations.

Depending on the physical layout and local law one could just extend house 1 to three phases and run one phase to each house. Full control at source. One external CT - well3 but one location e.g. Iammeter or one each for house 2 and 3.

When you have total excess you can play with software.

graph-under-load.png


I am just "programming" 4 p110 to control 3 washers and one dryer - max one at any one time....

Having the three separate feeds is a bit more challenging. Extra feed line, switching power supply, ....mhhh

Have fun



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Related Resources

MultiPlus-II Product page 

MultiPlus-II Manual

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