I want a fully off-grid system with Victron—who can help me?

DIY
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1

Hello,

Now that I have a digital meter, I would like to install batteries.

I am not allowed to change anything in my existing configuration, otherwise I will lose my certificates (Belgium). So, instead of sending the electricity converted by my panels to the grid, I first need to make sure my batteries are charged, and only send it to the grid once they are full. I need to have the option of going completely off-grid.
My panels provide a peak output of 8,500 watts in total. My current situation:

2 SMA (Sunny Mini Central SMC 4600A) inverters that feed the electricity into the grid on a single phase over two phases; I must not alter these.

What do I want?

I want to send the electricity generated by my panels / SMA units to my batteries first, and only send it to the grid once they are charged. The batteries must be able to supply three-phase power.

I want to work with

Victron MultiPlus-II 48V 6.5kVA 100A (3 units), because I also have a heat pump, but I would like to supply the rest of my house with electricity as long as there is enough charge in my batteries.

I have already done my research, and this is what I will need from Victron:

Victron Energy Cerbo GX MK2 ControllerVictron
Energy Lynx DC Distributor (M10) (2 units)
Victron Energy VM-3P75CT Energy Meter
Victron MultiPlus II 48V - 6K5VA - 100A (3 units)
Which battery? I would like to go for 25 kWh.
And I will also order the necessary cables and fuses.

The only thing I am missing is a wiring diagram showing me how to install everything.
Could anyone help me further?

Many thanks in advance.

2

Hi,

The best advice is to contact your local official Victron dealer for system design.

What you have in mind is perfectly feasible; I would use the system as a standard ESS. Going fully off-grid won’t work with “only” 25 kW of batteries.

My system is a three-phase MultiPlus II 5k with 20 kW of Pylontech batteries and 9,600 Wp of solar. My entire house runs on it, and now a heat pump as well. Even with this setup, going off-grid isn’t possible, although we use very little power from the grid between March and November.

3

A three-phase heat pump? In that case, a 25 kWh battery is rather small. Here I have a single-phase heat pump behind the Victron with 32 kWh of batteries, but even that could have been 45 to 50 kWh… Don’t underestimate the power consumption of the heating element; last winter, I once reached 10 kWh in a single day purely for defrosting.

4

What is the power rating of your heat pump? The Bosch 5800iaw 7OR-S runs perfectly well here on 20 kW batteries.

6

About 2200 watt for the compressor at 2 or 3 degrees of frost, I have seen 4300 watts at a defrost. Panasonic monoblock, unit bought in 2019

7

I’ve read several times that you have the Bosch 5800 heat pump.

Does it start up without any problems on the MultiPlus in off-grid mode?

8

Yes, it indeed works fine when the power goes out.

9

What kind of MultiPlus do you have?

Hope the heat pump also runs on a 3000 without the auxiliary heating.

10

3x multiplus 2 5000

11

The house is too small for that :wink: