Evaluation of Photovoltaic Offer and Components

The larger the photovoltaic system, the more likely it is that something will end up in the storage in winter, yes. But you have to convert these small daily yields into "production hours" to see whether the household doesn't consume all the yield anyway. Especially if you work from home

These small daily yields still come from our old, small system. The new one would have significantly more kWp and accordingly deliver more. Therefore, I don't believe the household can consume everything. Although these were really the January values. December and January are expected to be the worst months for the storage, logically. But February to November look different.

The larger the photovoltaic system, the more likely it is that some energy will end up in the storage even in winter, yes. But you have to convert these small daily yields into "production hours" to see whether the household does not consume all the yield anyway. Especially if you work in the home office. On the other hand, there is also a maintenance charge from the grid. 260 cycles is quite a lot. You would have to learn more about the system size and how the individual usage behavior looks. Individual values can be very misleading.

I have 10 kWp on the roof and a 10 kWh storage. I had already created my own thread on this topic some time ago. The thread had already pointed out that our usage behavior is not average. Of course, the values alone do not say much. You can see that just by comparing kati’s values with mine. She produced 31.701 kWh with her 4.55 kWp system in the period from 01/20/2022 to 01/31/2022. In the same period, I produced 129.1 kWh with my 10 kWp system. So more than 4 times the yield with only twice the system size. So it also has a lot to do with other factors such as the type of modules, orientation of the system, the location (apparently we had a bit more sun here during that period than she did), and many more.

There is the storage and the corresponding hybrid inverter. As a rule, there are certainly other more complex systems.

The settings for the storage are made via the inverter. The storage is connected there and does what the inverter specifies. Through the inverter, if it is a decent one and it harmonizes well with the storage, you can basically adjust everything.

For example, I chose a setting for myself so that the storage only charges when there is photovoltaic yield. So no electricity from the grid goes into my storage. Zero! Then the house network is supplied primarily and then the storage when the photovoltaic system is running. And when I have consumption, electricity is drawn from the storage until it is empty.

Therefore, I come to zero grid feed-in. (0.1 kWh per day are already lost, but that can be neglected)

On a sunny day like today, I expect about 30 kWh photovoltaic yield. The storage was 100 percent charged this evening around 6:00 p.m. Tomorrow we will have a rainy day and a photovoltaic yield of 3 kWh. Still, my grid feed-in will always be at zero.

My personal goal, to achieve as little grid feed-in as possible, is only possible with storage. To me, it was about a high self-consumption rate. Others want to do something for the environment and generate returns; they can fully cover their roofs and feed in as much as possible. They don’t need storage.

If you want to bake a chicken again at 10:00 p.m., have a 30 kWP system on the roof, and have to draw expensive electricity from the grid, it hurts. It only hurt me once when I bought the storage.

And one more thing about flexibility. I have, as is well known, installed a Huawei system, which also runs surprisingly stable. It is almost infinitely expandable. I can cascade the inverters. So I can put more modules on my roof and then dock a normal inverter to the hybrid inverter. I can expand my storage and also cascade it further. To my knowledge, it goes up to 90 kWh. I can connect a wind or water turbine, charge bidirectionally if an electric car should come at some point.

Somewhere I read a few days ago about a promotional price for a 10 kW storage for 2500 euros. So why shouldn’t that pay off?

Whoever installs a normal system without storage today will start again in 5 years. Because then storage will pay off and have become significantly cheaper. Then you start again. New inverter, smart meter, pulling data cables, etc. You might as well do it right away. Storage can still be expanded later.

Or then bidirectional charging is finally possible and you don't even need separate storage.

Or then bidirectional charging is finally possible and you don't even need an extra storage.

and the car is then loaded, in case the battery struggles with so much charging and discharging. I once found an example at Tesla, hundreds of cars with photovoltaic had no grid connection anymore, the island is self-sufficient