Battery Storage Capacity Calculator
Size your battery bank for solar or backup power. Calculates required Ah and kWh based on daily load and autonomy.
1. Energy Needs
2. Battery System
Total Stored Energy
0 kWhRequired Capacity
0 Ah @ 12VAbout
Designing a battery bank requires balancing total energy demand with the physical constraints of the storage medium. This calculator sizes battery systems for off-grid solar, RVs, or home backup, ensuring sufficient autonomy (days without power generation) while respecting the battery's depth of discharge (DoD) limits.
Undersizing a battery bank forces deeper cycling, which drastically reduces lifespan, particularly for lead-acid chemistries. Oversizing adds unnecessary cost and weight. By inputting your daily energy consumption and desired system voltage, you can determine the exact Amp-hour capacity required to maintain reliable power.
Formulas
Total Required Energy Etotal considers the Daily Load Edaily, Days of Autonomy D, and safe Depth of Discharge DoD:
To find the battery capacity in Amp-hours CAh at system voltage V:
Reference Data
| Appliance | Avg. Power (Watts) | Daily Use (Hrs) | Est. Daily Energy (Wh) |
|---|---|---|---|
| LED Light Bulb | 9 | 5 | 45 |
| Laptop | 60 | 8 | 480 |
| Refrigerator (Efficient) | 150 | 8 (cycle) | 1,200 |
| Television (LED) | 100 | 4 | 400 |
| Coffee Maker | 1,000 | 0.25 | 250 |