Battery Backup Calculator

Calculate UPS Battery Runtime | Backup Time in Hours, Minutes & Seconds

💡 Formula: Backup (hours) = (Ah × V × DOD%) / Load
Backup = (Ah × V × DOD%) / Load

📖 Battery Backup Calculator

This tool calculates the battery backup time for UPS, inverter, and solar battery systems. Enter battery capacity (Ah), voltage, load (watts), and depth of discharge (DOD) to get the estimated runtime in hours, minutes, and seconds. Essential for UPS sizing and power backup planning.

📐 Battery Backup Formulas

Backup Time (hours): T = (Ah × V × DOD) / Load
Energy (Wh): E = Ah × V
Usable Energy: E_usable = Ah × V × DOD / 100

📊 Typical Backup Times

BatteryVoltageLoadBackup Time
100Ah12V100W9.6 hrs
100Ah12V200W4.8 hrs
150Ah12V200W7.2 hrs
200Ah12V150W12.8 hrs
100Ah24V300W6.4 hrs

📌 Battery Types & DOD

Battery TypeMax DODRecommended
Lead Acid50%30-40%
Tubular80%50-70%
Lithium95%80-90%

❓ FAQ

How to calculate battery backup time? ▼
Backup time = (Ah × V × DOD%) / Load. This calculator does it automatically.
What is Depth of Discharge (DOD)? ▼
DOD is the percentage of battery capacity used. Lead-acid: 30-50%, Lithium: 80-90%.
How long will a 100Ah battery last? ▼
100Ah 12V at 80% DOD with 100W load = 9.6 hours. (100×12×0.8)/100 = 9.6h.
Which battery gives the best backup? ▼
Lithium-ion gives best backup due to higher DOD (95%) and efficiency.