Solar Battery Size Calculator
Calculate required battery capacity for solar energy storage
About this calculator
The Solar Battery Size Calculator helps homeowners and businesses determine the optimal battery capacity needed for their solar energy storage system. By calculating the right battery size, you can ensure reliable backup power during outages, maximize energy independence, and avoid over-investing in unnecessary storage capacity. This tool considers your daily energy consumption, desired backup duration, and system efficiency to recommend the most cost-effective battery solution for your solar installation.
How to use
Enter your daily electricity usage in kilowatt-hours (kWh), which you can find on your utility bill. Specify how many days of backup power you want during cloudy weather or outages. Select your battery type and system efficiency rating. The calculator will determine the minimum battery capacity needed in kWh to meet your energy storage requirements.
Frequently asked questions
How do I find my daily energy usage?
Check your electricity bill for monthly kWh usage and divide by 30, or use a smart meter to track daily consumption patterns.
What's the difference between usable and total battery capacity?
Usable capacity is typically 80-90% of total capacity, as batteries shouldn't be fully discharged to maintain longevity and performance.
Should I oversize my battery system?
A 20-25% buffer above calculated needs is recommended to account for battery degradation, seasonal variations, and unexpected higher usage periods.