What Is the Battery Coulombic & Round-Trip Energy Efficiency Calculator?
Round-trip efficiency measures what percentage of electrical energy supplied during charging is recovered during discharge.
How Does the Battery Coulombic & Round-Trip Energy Efficiency Calculator Work?
Energy is lost to parasitic chemical side reactions (Coulombic loss) and internal ohmic overpotential (voltage loss).
Battery Coulombic & Round-Trip Energy Efficiency Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
\eta_C = \frac{Q_{\text{dis}}}{Q_{\text{ch}}}, \quad \eta_V = \frac{V_{\text{dis}}}{V_{\text{ch}}}, \quad \eta_E = \eta_C \times \eta_V
Coulombic, voltage, and round-trip energy efficiency relations.
How to Use the Battery Coulombic & Round-Trip Energy Efficiency Calculator
- Input charge and discharge Ah capacities along with their corresponding average voltages.
Step-by-Step Example Calculation
Grid Storage Battery Cycle
Input Values:
chargeCapacityAh:50
dischargeCapacityAh:49
averageChargeVoltageVolts:3.8
averageDischargeVoltageVolts:3.6
Worked Steps: Yields 98.0% Coulombic efficiency, 94.7% voltage efficiency, and 92.8% round-trip energy efficiency.
Understanding Your Result
Shows Coulombic, voltage, and total energy efficiency plus thermal heat loss in Wh.
Factors That Affect the Result
- Higher charge/discharge rates create higher internal IR voltage drop, lowering voltage efficiency.
When Should You Use This Calculator?
- Grid-scale battery energy storage system (BESS) levelized cost of storage (LCOS) economic analysis.
Assumptions & Limitations
- Applies to full cycle at balanced state of charge.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard IEEE 1679 recommended practice for energy storage characterization.