Why the battery? Batteries are the least cost-effective part of any solar installation, especially on residential scales. You can buy this Balkonkraftwerk for

Why the battery? Batteries are the least cost-effective part of any solar installation, especially on residential scales. You can buy this Balkonkraftwerk for 1,099 Euros, it comes ready to plug in: https://solarhandel24.de/collections/balkonkraftwerke-mini-solaranlagen-zu-bestpreisen https://solarhandel24.de/collections/balkonkraftwerke-mini-s... If I scale down my (partially shaded) 12kwp installation, this 1.78kwp plant (which apparently is still legal under German legislation, which allows for up to 2kwp, not 0.8 kwp, as I erroneously wrote above), will generate 1.246 Mwh per year. If installed today, you'll get 7,94 Cents per kWh that you feed into the network and buying electricity comes at about 29 Cents/kwh. If you consume half of the Balkonkraftwerk's generation directly you'll save 180 Euros. If you feed in the other half, you'll get paid almost 50 Euros. At 230 Euros per year, you'll have recouped your investment after 4.77 years. A battery does not make any sense on that scale. It would severely decrease return on investment because its main use case (running asynchronous high loads like heating and charging cars) are not available in this type of installation. Pure PV installations (without any battery) are practically always profitable within 10 years in Germany, as long as you can guarantee at least 50%, better 70% direct consumption and your plant is not pointing straight north and/or is shaded completely. Batteries are nice to play with (and ours would have a 12 year break even time at current prices) but if I'd optimize for ROI, I'd never include them and instead scale down the kwp of my solar to hit 65-75% guaranteed direct consumption.