ᐅ Photovoltaic system with future battery upgrade: What do I need to consider?

Hello!

I am currently getting familiar with the topic of photovoltaics. At the moment, I am still focused on the basic technology and have not yet reached the point of dealing with complicated calculations or VAT issues 🙂

I want to cover the roof of our house, which is currently in the planning stage, as fully as possible with solar panels. According to the current plan, we have a gable roof facing 20° southwest with a 35° pitch. When I use common online calculators, the results suggest a system size of around 16-18 kWp, while the inverter mentioned later seems to support 15 kWp, if I understand correctly.

The goal is, of course, to make the most efficient use of sunlight throughout the day and possibly to retrofit a battery storage system later on. Depending on the offer, the battery might be installed directly during construction. Ideally, the system could supply the house with three-phase power during a blackout, and even better if it could operate continuously like an online UPS (I’m not sure if that is possible). An electric vehicle will also be added soon, and we already have an OpenWB Series2 Standard+ wallbox installed.

Since the wallbox installer is also the local solar technician, I briefly interviewed him about photovoltaics. He typically installs SMA, Fronius, Kostal, or E3DC systems. Google has already shown me that the Fronius Symo GEN24 PLUS is a pretty good inverter and supports my backup power plans (standard has single-phase output via socket, but it can apparently be upgraded to full backup with all phases). For panels, I would like to use the Hyundai S395VG All Black because I don’t want a blue-colored roof.

What exactly do I need for this (I mean everything except wiring or mounting materials)? The Fronius GEN24 PLUS inverter, the Fronius Smart Meter, the panels, the utility connection box for OpenWB? From what I understand, BYD batteries are compatible.

As I said, the solar technician will surely be able to tell me all this, but I would like to be somewhat knowledgeable as well. So far, only the bare OpenWB Standard+ is installed.

What exactly is the question?

Full black modules are available from various manufacturers.
Storage only makes sense if there is a subsidy (KFW40+ etc.).
Full emergency power supply for the whole house is rarely easy to achieve.
Usually, a transfer switch and similar equipment are required.

The question is exactly about something like a switch, as you mentioned. As I wrote, I want to know which devices I need for the project. So far, I know about the inverter with smart meter, the battery storage, and of course, the modules. For example, if I want to use surplus charging with the OpenWB, the inverter or the communication between the OpenWB and the inverter can handle that. Without such an inverter, I would need, for instance, the EVU kit from OpenWB. These are the kinds of components I’m referring to 🙂

You asked me this in another thread. So now from our side, what exactly is the question or requirement?

To retrofit a (DC) storage system, you need a compatible inverter. That’s basically all there is to it.

You don’t need the utility company kit for the electric boiler if the Fronius Smart Meter (or a comparable device) is installed.

Tarnari schrieb:

You asked me this in another thread. So now from our side, what exactly is the question or requirement?

😎

Okay, I’ll try to summarize again. I want to:
- Make optimal use of solar energy throughout the day (the house will have KNX, at least one 4-zone split air conditioner, and possibly a small pool with a heat pump later)
- Store excess energy and use it during periods of low sunlight
- Use the storage system as a three-phase backup power supply for the house and possibly achieve some filtering
- Charge the car with excess energy (also from the battery)
- Feed any remaining energy back into the grid if there is surplus

Question:
- What technology do I need for this?

So far, I’ve found that I obviously need panels, an inverter, a smart meter, a storage system, and my wallbox. From this thread, I’m still wondering if I need a transfer switch for backup power operation with the wallbox I mentioned.

guckuck2 schrieb:

To retrofit a (DC) storage system, you need a suitable inverter. That’s basically it.

You don’t need the utility company kit for the on-board charger if the Fronius Smart Meter (or an equivalent) is installed.

Thanks! The Fronius GEN24 PLUS should be capable of that, according to what I’ve read. It makes sense that the utility company kit isn’t required when using the Fronius Smart Meter. Now the next question is whether I need an additional device for switching to backup power with this inverter. From what I understand from the Fronius website, that is not necessary, even if more than just the small integrated photovoltaic point is used.