Batteria Domestica Capacità Calculator: How Many kWh Do You Need?

Why calculating capacità matters

The capacità of your batteria domestica (expressed in kWh) determines how much energy you can store. Choose too small and you'll still lose surplus energia solare. Choose too large and you'll pay for capacità you don't use. The right capacità depends on your consumption pattern, the size of your pannello solare installazione and your nucleo familiare composition.

In this article, we give you the rules of thumb, worked examples and tables to determine the ideal capacità for your situation. You only need your annual consumption and the number of pannelli solari.

Fase 1: Determine your daily consumption

The average Dutch nucleo familiare consumes circa 2,800 kWh all'anno, or about 7.7 kWh al giorno. But actual consumption varies considerevolmente between nuclei familiari. Factors that play a role:

• Household size: a single person uses ~2,000 kWh/year, a family with children 3,500-5,000+ kWh/year
• Electric car: adds 2,000-4,000 kWh/year to your consumption
• Pompa di calore: adds 3,000-6,000 kWh/year
• Working from home: circa 300-500 kWh extra all'anno
• Electric cooking: circa 200-400 kWh extra all'anno

Fase 2: Calculate your daily surplus

The capacità della batteria you need is largely determined by the difference between your energia solare generation and your actual consumption at that moment. In pratica, you only use 30-40% of your energia solare directly during the day. The rest is surplus. Here is an indicative table:

Rule of thumb: choose a capacità della batteria equal to 60-80% of your daily surplus in summer. In winter you produce less, but elettricità prices are higher — the batteria is then also charged via tariffe dinamiche.

Fase 3: Consider your consumption pattern

It's not just the amount of consumption that matters, but also when you consume. This determines how much energy you draw from your batteria in the evening and at night.

Working from home during the day

If you're at home during the day, you use more energia solare directly. You then need less capacità della batteria because there is less surplus. A batteria of 3-5 kWh is often sufficient for nuclei familiari with home workers and 8-12 pannelli solari.

Not at home during the day

If you're away during the day (work, school), praticamente all energia solare is surplus. Here you need a larger batteria to capture it all. Expect 5-10 kWh for an average nucleo familiare with 10-14 panels.

Family with high evening consumption

Cooking, washing machine, dryer, TV, lighting: families with children consume the most between 17:00 and 22:00. A batteria of 8-15 kWh is then needed to cover the evening peak.

Worked example

Suppose: you have 12 pannelli solari (4.8 kWp), consume 3,500 kWh all'anno and are not at home during the day.

Common mistakes when choosing capacità

These are mistakes we see regularly:

• Choosing too small: a 2 kWh batteria with 14 pannelli solari is a waste — you'll still lose most of your surplus
• Forgetting winter production: in winter you produce only 20-30% of your summer capacità. An oversized batteria won't be fully charged by energia solare (but it will be via tariffe dinamiche)
• Ignoring future consumption: planning an EV or pompa di calore? Factor those extra kWh into your choice
• Not thinking modularly: choose a system you can expand later as your consumption grows

Conclusion and advice

The right capacità depends on your specific situation. As a rule of thumb: a batteria of 5-10 kWh is suitable for most nuclei familiari with 8-14 pannelli solari. For larger installations or nuclei familiari with an EV/pompa di calore, we recommend 10-20 kWh.

Unsure about the right capacità? Use our free savings calculator or request personal advice. We'll help you make the optimal choice.