UPS Battery Calculator
Calculate the number of batteries needed for your UPS system
System Requirements
Watts
Hours
Series
Increase voltage
Parallel
Increase capacity
Series-Parallel
Both voltage & capacity
Single Battery
Direct connection
Calculation Results
Batteries Required
4 batteries
2 series × 2 parallel
Total Battery Capacity
96 Ah
76.8 Ah usable
Expected Runtime
2.3 hours
At full load with 80% DoD
Recommended Setup
Connect 2 batteries in series to reach 24V, then connect 2 of these series strings in parallel.
Note: Always use batteries of the same type, age, and capacity for optimal performance.
Common Battery Types
7Ah Sealed Lead Acid
Small UPS, routers, modems
12Ah Sealed Lead Acid
Standard UPS, computers
18-24Ah Sealed Lead Acid
Extended runtime UPS
38-65Ah Sealed Lead Acid
Rack mount, server UPS
100Ah+ Deep Cycle
Industrial, solar systems
Calculation Formulas
Total Energy Required
Energy (Wh) = Power (W) × Time (h) ÷ Efficiency
Battery Capacity Required
Capacity (Ah) = Energy (Wh) ÷ Voltage (V) ÷ Depth of Discharge
Number of Batteries
Batteries = Total Capacity (Ah) ÷ Battery Ah × Configuration Factor
Configuration Factors:
• Series: Batteries in series increase voltage
• Parallel: Batteries in parallel increase capacity
• Series-Parallel: Combination of both
