🔋 Energy Storage Calculator
Enter your daily energy use, days of autonomy, depth of discharge, and system voltage to size the battery bank you need — in both usable kilowatt-hours and amp-hours.
🔋 Size Your Battery Bank
What is an Energy Storage Calculator?
An energy storage calculator turns your daily power needs into a battery bank size. It accounts for how many days of backup you want and how deeply you can safely discharge the cells, so the bank is large enough to last without being prematurely worn out.
Enter daily consumption, days of autonomy, depth of discharge, and system voltage to get the required usable capacity in kWh and the equivalent amp-hours. These are estimates for planning, not professional electrical or engineering advice.
❓ Frequently Asked Questions
How do I size a battery bank for my home?
Start with your daily energy use in kilowatt-hours, multiply by the number of days you want to run without recharging (days of autonomy), then divide by the allowable depth of discharge. Sizing 10 kWh/day for one day at 80% DoD gives a 12.5 kWh bank, because you never want to fully drain the batteries.
What is depth of discharge and why does it matter?
Depth of discharge is how much of a battery's capacity you regularly use. Drawing a battery down to 80% (leaving 20%) is gentler than running it flat, so you size the bank larger than your raw need to protect cycle life. Lithium banks tolerate deeper discharge than lead-acid, which changes the number meaningfully.
Why does the calculator show amp-hours as well as kWh?
Batteries are often rated in amp-hours at a nominal voltage (12 V, 24 V, or 48 V), so converting your kWh requirement into amp-hours at your system voltage tells you how many cells or modules to wire together. The same 12.5 kWh is about 260 Ah at 48 V but over 1,000 Ah at 12 V.
Is this battery sizing exact?
No — these are estimates for planning, not professional electrical or engineering advice. Real designs also account for inverter efficiency, temperature derating, charge sources, and safety margins. Use this to scope a system, then confirm with a qualified installer.