Advanced Battery Capacity & Runtime Calculator

Complete solution for solar projects, backup power, and energy planning

Runtime Calculator
Capacity Calculator
Solar Sizing
Battery Comparison

Input Parameters

50% (Poor) 95% (Excellent)
Recommended: 50% for Lead-Acid, 80% for Lithium

Results & Visualization

100% Capacity
Battery Energy
--
Wh
Usable Energy
--
Wh
Estimated Runtime
--
Load Current
--
A
Discharge Rate
--
C
Energy per Day
--
Wh/day

Runtime at Different Loads

Required Capacity

Calculate the battery capacity needed for your specific runtime requirements.

Capacity Results

Required Battery Capacity
--
Ah
Total Energy Required
--
Wh
Recommended Battery Size
--
Ah
Number of Batteries (100Ah)
--

Battery Selection Tips

  • Add 20% extra capacity for aging and efficiency losses
  • For series connection: Voltage adds, capacity stays same
  • For parallel connection: Capacity adds, voltage stays same
  • Consider temperature derating for cold environments
  • Lithium batteries provide more usable capacity than Lead-Acid

Solar Panel Sizing

Solar System Results

Required Solar Power
--
W
Battery Bank Size
--
Ah @ 12V
Number of Panels (300W)
--
Daily Energy Generated
--
Wh

Compare Battery Types

Battery Type Energy Density Cycle Life Cost per kWh Efficiency Best For
Lead-Acid (Flooded) 30-50 Wh/kg 200-300 cycles $100-$150 75-85% Budget backup
Lead-Acid (AGM) 30-50 Wh/kg 300-400 cycles $150-$250 85-90% Solar systems
Lead-Acid (Gel) 30-50 Wh/kg 500-800 cycles $200-$300 85-90% Deep cycle use
Lithium-ion (LFP) 90-120 Wh/kg 2000-3000 cycles $300-$500 95-98% Solar/EV
Lithium-ion (NMC) 150-200 Wh/kg 500-1000 cycles $250-$400 95-98% Portable devices

Battery Type Comparison

Common Load Presets

Quickly calculate runtime for common household and electronic devices:

LED TV
80W
55" Smart TV
Laptop
60W
Standard laptop with charger
WiFi Router
10W
Home router + modem
Refrigerator
150W
Medium-sized fridge
LED Lights
30W
Set of 5 LED bulbs
Ceiling Fan
70W
Standard ceiling fan
Phone Charging
5W
Smartphone charging
Gaming PC
400W
High-end gaming computer

Battery Runtime Formula

  • Battery Energy (Wh) = Voltage (V) × Capacity (Ah)
  • Usable Energy (Wh) = Battery Energy × DoD (%) × Efficiency (%)
  • Runtime (hours) = Usable Energy ÷ Load Power (W)
  • Load Current (A) = Load Power (W) ÷ Voltage (V)
  • Discharge Rate (C) = Load Current (A) ÷ Battery Capacity (Ah)

Pro Tips

  • For solar systems, size your battery for 2-3 days of autonomy
  • Keep Lead-Acid batteries above 50% state of charge for longevity
  • Lithium batteries perform better in cold temperatures than Lead-Acid
  • Add 20-30% extra capacity for future expansion
  • Use a battery monitor for accurate state-of-charge readings