PV Battery Storage Calculator
Calculate the recommended battery storage size for your solar system based on usage and generation.
The right battery size depends on daily consumption, PV production and your target self-sufficiency. This calculator gives a rule-of-thumb recommendation in kWh.
Pro tips
- A larger battery usually only pays off if there is enough PV surplus.
- Usable capacity is often 10-20% below the rated capacity.
Frequently Asked Questions
How big should my solar battery be?
A rule of thumb is about 1 kWh of storage per 1,000 kWh of annual electricity consumption – the calculator above refines this using your consumption and PV output.
What self-sufficiency is realistic with a battery?
A well-sized battery usually achieves 60-80% self-sufficiency; 100% is barely realistic in practice without going off-grid.
Is a bigger battery always worth it?
Not necessarily – beyond a certain size, self-sufficiency barely increases further while the cost per kWh of storage keeps rising.
How long does a solar battery last?
Most lithium batteries are rated for 6,000-10,000 charge cycles, or 10-15 years, depending on usage and battery technology.