Solar Battery Size Calculator
Find a useful battery size for your PV system. The calculator compares smaller, suitable and larger batteries and shows where extra capacity adds little value.
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The battery size calculator shows not only a battery size, but also whether a larger battery still adds meaningful economic value.
Frequently asked questions
What battery size is useful?
A useful size is often close to the demand that can realistically be shifted into evening or night hours. The calculator shows when extra capacity adds little value.
Why can a smaller battery be more economic?
Smaller batteries are used more often. Larger batteries may increase autonomy but can perform worse economically.
Is the recommended size a purchase recommendation?
No. It is an orientation based on simplified assumptions. Quotes, load profile, warranty, efficiency and installation must be checked separately.
Why does the size comparison matter most?
Because this calculator is not mainly about whether a battery pays off. It shows where extra capacity starts to add much less value.
Does the calculator include winter and weather?
Only in a simplified annual model. Monthly data and load profiles are more accurate for real design.