Single-family house photovoltaic system with 30KW

Hello everyone,

due to the fact that the photovoltaic modules are currently very cheap, I would like to purchase the photovoltaic modules, substructure, inverter, and battery storage in advance.
Key data:
Single-family house in Landkreis Altötting, 2 adults, 2 children
Roof north/south orientation
Roof area 13.5m x 6.7m
Size of photovoltaic module => 1.69 x 1.0 m
=> 3 rows of 12 modules => 36 modules per side
36 pieces on the west side and 36 pieces on the east side
Therefore, I would buy 72 modules (410 W modules) in advance.

Therefore, I come to about 30 KW

The heating is planned through heat pump + hot water storage
I estimate the annual consumption at 4.5 KW, as I also want to install 2 or 3 air conditioning split units.

My questions therefore are:
Do you think that 30 KW is oversized?
What size battery storage would you recommend?
Which inverter can you recommend to me?

Thanks in advance

Do you think that the 30 kW is oversized?

No - push it as far as you can.

What size of battery storage would you recommend to me?

Depends on whether you can buy yourself and only need an electrician for the connection. Buy yourself = easily > 10kWh. Through a company = probably not at all

Which inverter can you recommend to me?

I’m out on which devices you need - one inverter will not be enough. Depends on the design of the system.

Storage and inverters must match. Not every storage system can work with every inverter.

Personally, I think very highly of the Huawei system. There are some features that others don’t have. My system has been running stably for 2 years. Starting with the app, the Wi-Fi connection, the storage and the inverter are cascadeable, meaning expandable.

In addition, the storage can be expanded and the system levels itself automatically. Others can’t do that. Furthermore, with the Huawei Backup Box, you can make the system emergency power and island capable. The appearance, the workmanship, everything is very high quality. I have only ever had Huawei phones so far, so it made sense to switch to the Huawei system as well. I can only recommend it to everyone. Everything else is exotic. Maybe Fronius with BYD storage. But that becomes twice as expensive right away.

Buying the components is very good. Prices are rock bottom and exempt from VAT in Germany. There won’t be a better time.

For 30 kWp, I would take a 15 kW storage.

But you can calculate everything yourself. In winter, nothing comes from the roof no matter how much you have on it. That’s just how it is.

I have a 7.2 kWp system and a Huawei Sun inverter, three-phase hybrid 6 KTL, so with a maximum output of 6 kW. That’s also the peak output of the system. With it, I generate roughly 5-6000 kWh of electricity.

That is more than enough for me. About 2500 kWh of it is fed back into the grid. I just can’t use that. What do you want with such a large system? You can do it, but you don’t have to. You can just as well fill your garden with modules, build a photovoltaic garden fence, or put up a BW carport.

I have a similar set up as you are planning on the roof. Just under 28kWp on a gable roof with north and south sides. Roof pitch 23°.

Inverter can do 25kW (that is more than enough) from SolarEdge. I also installed the optimizers from Solar-Edge (recommendation!).

I have two storage units: one with 42kWh and one with 84kWh.

The great thing about them is: they even have wheels and a steering wheel on them, so I can drive to vacation with them!

Thank you very much for your answers. I tend towards 30KW and a battery storage of about 12-15 KW. Since I installed photovoltaic systems in my youth, I only need an electrician for the connection.

I just don't know which inverter+battery storage to choose.

Maybe like this?
Inverter:
2x Huawei SUN2000-10KTL-M1 Hybrid Inverter High Current Version (tepto.de)
And storage:
3x Huawei LUNA2000-5-S0 - Storage package 5 kWh (tepto.de)

Although the Huawei storage seems a bit expensive to me.
Alternative:
PYLONTECH Force H3 HV 400V LiFePO4 High-voltage battery power storage system 3x module 15.36 (Photovoltaik.lichtex.de/)

A little tip on the side, since last year I believe there have been some requirements from the grid operator to install a shut-off device starting from 25KW. This allows them to avoid your feed-in, for example in midsummer, when too much electricity is fed into the grid. The components for this alone were roughly around €1000 when I looked into it, and you also need space in the cabinet. Then the question is whether it makes sense to go over 25KW...