Energy need × backup days
Multiply your daily energy use by the number of backup days. Then divide by your depth-of-discharge limit so you never drain batteries below their safe level.
Off-grid energy storage, simplified
Size your battery bank in seconds.
Built for Saudi conditions. Tell us how much energy you use per day, how long you need backup, and what batteries you have. The tool figures out how many you need and how to wire them.
Calculator inputs
Pick a battery you have or plan to buy. For custom batteries, common lithium values like 12.8V, 25.6V, and 51.2V are compatible with 12V, 24V, and 48V systems.
Your battery bank.
How many batteries you need and how to wire them.
Enter your daily energy use and backup days above to see results.
Energy needed
--
Required bank size
--
Installed capacity
--
Usable capacity
--
Battery bank voltage
--
How to wire
--
Total batteries
--
Safety margin
--
Storage sizing only — not installation design. This tool estimates battery bank size. It does not size inverters, solar panels, fuses, breakers, cables, or ventilation. Install batteries in an indoor, ventilated, temperature-controlled location away from direct sun. In Saudi summer conditions, high heat (>35°C) can reduce battery life; avoid uncooled outdoor enclosures. Always check manufacturer limits for series/parallel configurations and BMS current ratings. Have your final design reviewed by a qualified installer.
How it works.
Three numbers that determine your battery bank size.
Temperature adjustment
Cold batteries deliver less capacity — at -10°C about 75% is available. Above 25°C short-term capacity is full, but extreme heat can shorten battery life; keep batteries in a ventilated, temperature-controlled space away from direct sun.
Match voltage with series + parallel
Batteries in series increase voltage; in parallel increase amp-hours. The tool finds the right combination to match your system voltage and deliver the capacity you need.
Technical details.
Assumptions and methods behind the numbers.
How to use these results
- Energy needed is your daily use times backup days. This is the minimum energy your bank must store.
- Required bank size is the nominal capacity needed after accounting for DoD and temperature limits.
- Installed capacity is the actual nominal size of the battery bank you would build with whole batteries.
- Usable capacity is what you can actually draw from the installed bank after DoD and temperature derating.
- How to wire shows the configuration: 4S3P means 4 in series and 3 parallel strings — 8 batteries total.
A note on real-world conditions
This tool provides a conservative estimate. In practice, factors like battery age, charge/discharge rates, and inverter efficiency will affect real-world performance. Always add a 10–20% safety margin and consult your battery manufacturer's specifications.