This calculator works out battery bank for daily solar-supported energy and autonomy. Daily energy and autonomy are expanded for allowable discharge and system losses to estimate nominal battery-bank energy and Ah. Replace the example values with information from your own label, bill, drawing, product sheet or land record. Confirm battery chemistry, cycle-life target, bank voltage, maximum current and whether grid backup reduces the required autonomy. The formula and every editable assumption remain visible so the result can be checked before it is used for planning. Keep the values and result together when you compare or share this planning scenario.
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Every input includes a simple explanation.
Private: calculations run in your browser. Saved scenarios, preferred electricity rate and land state stay on this device.
Motors and compressors can need extra power when they start.
Battery age, temperature and a high discharge rate can reduce delivered energy.
Use this as a planning range. Confirm continuous rating, peak rating and battery compatibility with the manufacturer and a qualified installer.
Read the meaning first, verify the important details, then avoid the most common planning error.
Daily energy and autonomy are expanded for allowable discharge and system losses to estimate nominal battery-bank energy and Ah.
Confirm battery chemistry, cycle-life target, bank voltage, maximum current and whether grid backup reduces the required autonomy.
Sizing from solar-panel watts alone ignores the household energy that must be carried through non-solar hours.
Updated 17 July 2026. Changes listed here describe this calculator release; they are not invented historical entries.