Battery Energy Calculator

Calculate battery energy capacity, consumption, and storage requirements for electrical system design and energy analysis.

Nominal battery voltage
Battery amp-hour capacity
Power consumption of connected load
Overall system efficiency (default: 90%)

Energy Calculation Results

Total Energy Capacity: 0 Wh
Usable Energy: 0 Wh
Energy in kWh: 0 kWh
Runtime at Load: Not calculated
Energy Density: 0 Wh/V
Cost per kWh: Enter cost to calculate

Understanding Battery Energy Calculations

Battery energy calculation is fundamental to energy storage system design, helping engineers determine storage capacity, runtime, and system requirements. Energy represents the total amount of electrical work that can be performed, measured in watt-hours (Wh) or kilowatt-hours (kWh).

Energy Calculation Formulas

Basic Energy Formula:

Energy (Wh) = Voltage (V) × Capacity (Ah)

Runtime (hours) = Energy (Wh) / Power (W)

Usable Energy = Total Energy × (Efficiency / 100)

Energy Density = Energy (Wh) / Voltage (V)

Key Concepts

  • Energy vs. Capacity: Energy (Wh) includes voltage, while capacity (Ah) is just charge storage
  • Usable Energy: Practical energy available after system losses and efficiency
  • Energy Density: Energy storage per unit of voltage, useful for comparison
  • Depth of Discharge: Maximum safe energy extraction without damage

Practical Applications

Energy calculations are essential for:

  • Solar energy storage system sizing
  • Electric vehicle range determination
  • Backup power system design
  • Off-grid power system planning
  • Cost analysis and energy economics
Important Considerations
  • Actual energy capacity may be lower than theoretical due to temperature, age, and discharge rate
  • Different battery chemistries have varying voltage curves during discharge
  • System efficiency includes losses in converters, inverters, and charge controllers
  • Consider depth of discharge limits for battery longevity
  • Energy density calculations help compare different battery technologies

Frequently Asked Questions

How do you calculate battery energy capacity?

Battery energy capacity is calculated using the formula: Energy (Wh) = Voltage (V) × Capacity (Ah). For example, a 12V battery with 100Ah capacity has an energy capacity of 1,200Wh or 1.2kWh. Energy can also be calculated as Power × Time. Understanding energy capacity is essential for sizing battery systems, determining runtime, and comparing different battery technologies.

What's the difference between energy and power in batteries?

Energy is the total amount of electrical work a battery can perform (measured in watt-hours), while power is the rate at which energy is delivered (measured in watts). Energy = Power × Time. A battery might have high energy capacity for long runtime but limited power capability for high-current applications. Both metrics are crucial for proper battery system design.

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