What solar battery capacity do you need?
Sources checked
Choose battery capacity from demand after solar generation ends and the surplus available to charge it. Panel rating and annual consumption alone cannot tell you whether 5 kWh, 10 kWh or more is appropriate.
Compare timing before capacity
Use interval readings where available. Identify energy needed overnight and recurring midday surplus, then compare representative seasons. A battery can only shift energy that is actually available; it cannot solve a prolonged winter generation deficit.
Distinguish nominal capacity, usable capacity and the reserve held back for backup. A 10 kWh label does not prove that 10 kWh reaches appliances in every cycle.
Check power and marginal benefit
Ask for continuous charge/discharge power in kW and any per-phase restrictions. A battery with enough stored energy may still be unable to start a pump or supply several large appliances together.
Compare 5 and 10 kWh using the same generation and demand assumptions. The extra useful energy from the larger battery may be small. The reference calculator supports this comparison, but its assumed household profiles are not measurements of your home.