Lithium Battery Backup Calculator

Calculate backup time and battery capacity for your power needs

Lithium Battery Backup Calculator

Professional Battery Sizing Tool

Results:

Backup Time: 0.00 hours

Required Capacity: 0.00 Ah

Energy Storage: 0.00 Wh

Current Draw: 0.00 A

Battery Life Calculator
Battery Capacity Calculator

How to Use the Calculator

Calculate Backup Time

  1. Select "Calculate Backup Time"
  2. Enter your power load in watts
  3. Input battery capacity in Ah
  4. Select or enter battery voltage
  5. Adjust efficiency and DoD settings

Calculate Battery Capacity

  1. Select "Calculate Battery Capacity"
  2. Enter your power load in watts
  3. Input desired backup time in hours
  4. Select or enter battery voltage
  5. Adjust efficiency and DoD settings

Key Parameters

  1. Power Load: Total watts to be powered
  2. Battery Voltage: System voltage (12V, 24V, 48V)
  3. Efficiency: Inverter/system efficiency (80-95%)
  4. DoD: Safe discharge depth (70-90% for lithium)

Battery Backup Fundamentals

Lithium Battery Advantages

Lithium batteries offer superior performance:

  • Higher depth of discharge (80-90%)
  • Longer cycle life (3000-5000 cycles)
  • Better efficiency and faster charging
  • Lighter weight and compact size

System Efficiency

  • Inverter efficiency: 85-95%
  • Battery discharge efficiency: 95-98%
  • Wiring and connection losses: 2-5%
  • Overall system efficiency: 80-90%

Key Formulas:

Backup Time = (Battery Capacity × Voltage × DoD × Efficiency) / Power Load

Required Capacity = (Power Load × Backup Time) / (Voltage × DoD × Efficiency)

Current Draw = Power Load / (Voltage × Efficiency)

Calculation Formulas

Backup Time (hours):
T = (C × V × DoD × η) / P

Battery Capacity (Ah):
C = (P × T) / (V × DoD × η)

Energy Storage (Wh):
E = C × V × DoD

Example Calculation

12V Lithium Battery System:

Power Load: 500W

Battery: 200Ah, 12V

DoD: 80%, Efficiency: 85%

Backup Time = (200 × 12 × 0.8 × 0.85) / 500

Backup Time = 1632 / 500 = 3.26 hours

Energy Storage = 200 × 12 × 0.8 = 1920Wh

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