Battery Bank Sizing Calculator
Calculate battery bank size for backup power systems and off-grid applications
About this calculator
The Battery Bank Sizing Calculator helps determine the optimal battery capacity needed for backup power systems, solar installations, and off-grid applications. By calculating the right battery bank size, you can ensure reliable power supply during outages or when disconnected from the grid. This tool considers your power consumption, backup duration requirements, and battery specifications to prevent undersized systems that fail during critical moments or oversized systems that waste money and space.
How to use
Enter your total daily power consumption in watts or kilowatt-hours, specify how many days of backup power you need, and input your battery voltage and depth of discharge limits. The calculator will determine the required battery capacity in amp-hours and suggest the number of batteries needed for your system.
Frequently asked questions
What is depth of discharge and why does it matter?
Depth of discharge (DoD) is the percentage of battery capacity you can safely use. Lead-acid batteries typically allow 50% DoD, while lithium batteries can handle 80-90% without damage.
How do I calculate my daily power consumption?
List all devices you want to power, multiply their wattage by daily usage hours, then sum the total. Add 20% safety margin for inefficiencies and unexpected usage.
Should I oversize my battery bank?
Yes, sizing 20-25% larger than calculated needs accounts for battery aging, temperature effects, and future power requirements while extending overall battery life through gentler cycling.