Solar Battery Size Calculator

Enter your PV array size, sun hours and daily use — see the right battery capacity in kWh, your self-sufficiency %, and a recommended LiFePO4 model. No email required to use it.

Daily generation = array kW x sun hours, derated ~10% for system losses. Recommended capacity targets your evening/overnight load so the battery cycles daily. Figures are indicative; a tailored quote confirms exact sizing.

— kWh
recommended battery capacity
Your solar & storage at a glance
MetricValue
Daily solar generation
Usable solar energy
Self-sufficiency (solar + stored)
Excess exported to grid

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Sizing FAQ

How many kWh of battery do I need per kW of solar?

A practical rule of thumb is 1–2 kWh of battery per kW of PV for self-consumption. A 5 kW array on a typical home pairs well with a 5–10 kWh battery; the exact size depends on your evening use and how much solar you want to capture instead of exporting.

Should I size the battery to my whole solar output?

No. Storing 100% of midday peak generation is usually wasteful — you would rarely fill it. Size to your evening/overnight load (roughly 40–60% of daily use) so the battery cycles fully every day, which is better for payback and battery life.

Is LiFePO4 better than lead-acid for solar storage?

Yes. LiFePO4 supports 80–100% depth of discharge versus ~50% for lead-acid, and lasts 5,000+ cycles versus ~500. That means you need a smaller nameplate to get the same usable kWh, and it is far cheaper per kWh delivered over its life.

Can I add more battery to my solar system later?

Yes. Modular systems such as NovaBESS HomeStack parallel from 5 kWh up to 60 kWh, so you can start with what your array and budget allow and expand as your use grows.

Want a real size for your roof?

Tell us your array size, country and daily use — we'll respond with a configured LiFePO4 solution and distributor or OEM pricing.

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