UPS Battery Sizing Calculator

Calculate battery capacity for uninterruptible power supply systems.

Total critical load in watts
Required backup duration

UPS Battery Design Factors

  • Depth of Discharge: Lower DOD extends battery life
  • Aging Factor: Accounts for capacity loss over time
  • Temperature: Battery capacity decreases in cold
  • Discharge Rate: High rates reduce effective capacity
  • Recharge Time: Plan for charger sizing

Battery Life vs Depth of Discharge

DOD VRLA Cycles Li-Ion Cycles Life @ Daily Use
50%1200-15003000-50003-4 years
60%800-10002500-35002-3 years
70%500-7002000-30001.5-2 years
80%300-5001500-25001-1.5 years
90%200-3001000-15006-12 months