Photovoltaic system: Advantages and disadvantages, experiences, worthwhile?

Anyone got a tip on how/where to get the KFW 270 as a standalone product?

Thanks!

Heat pump, circulation line, 2 households, small child, tumble dryer, 3 refrigerators, air conditioning, rain shower... highest self-sufficiency rate was 88%. if I turn off air conditioning, circulation line and ventilation, certainly >90%. but do I want that?

For us, it is almost exactly your setup, just without air conditioning, my self-sufficiency for June 19 is 95%, July 19 is 91%, and August 19 is 90%.

We have 9.2kWp on the roof and 10.5kW storage.

KfW is at 1.03%...

79€ sounds pretty good, but that doesn't cover the monthly electricity consumption, right?

I don't pay 1800€ interest for the 15k over 15 years, I thought we were below 1% there. The 79€ is the installment to the KfW.

The interest is operating expenses

There are also rental models but I have never seen them profitable. Especially in times of 1% interest.

I am currently considering getting a battery storage system.
It's unfortunate because it's too late for subsidies (Just left 1k€ lying around, battery subsidy 10,000 Houses Program), but that's how it is now. I had a Kostal Plenticore 8.5 Plus installed, just in case I feel like it, so only the battery is necessary. My solar installer mentioned a price yesterday: €3750 net + installation for the BYD BOX HV 6.4 kWh version.

Question: The system on the south roof has 8.68 kWp,

1. Does a BYD HV battery with 7.7 kWh make sense due to the size?
2. I usually get home around 4-6 pm and can currently charge my electric car (14 kWh Kappa) for 2 hours with 3.1 kWh, then logically have less photovoltaic supply until dusk. At some point it switches and I draw from the grid. It would be bad if the car empties the battery until (no idea 10 pm) and the consumers at night (controlled residential ventilation, refrigerator, hot water, etc.) need more than the car used!
Does the battery make sense with the car? Or is increasing the self-sufficiency rate through an additional battery already disproportionate because of the electric car? I will have a self-sufficiency rate over 40% (felt) without a battery (because the car itself can be considered a battery).

...and now please don’t tell me I should get a bigger battery.

With us, it is almost exactly your setup, just without air conditioning. My self-sufficiency for June 19 is 95%, July 19 is 91%, and August 19 is 90%.

We have 9.2 kWp on the roof and a 10.5 kW battery.

3.6 KWP south, 1.8 KWP west (5.4 KWP total)

and an LG 7 KWH battery, which can be charged with about 6. So pretty much half of what you have. What did you pay?