Understanding Theoretical Battery Run Time
Calculating the theoretical run time of a battery requires analyzing more than just simple division of capacity by load. Real-world electrical performance is governed by multiple variables including discharge rates, chemical composition limits, environmental temperatures, and system conversion inefficiencies.
Formula Used
The core estimation is derived from energy conversion and Peukert's law adjustments:
- Basic Energy Equation: $$Energy (Wh) = Capacity (Ah) \times Voltage (V)$$
- Peukert's Law: $$t = \frac{C^k}{I^k}$$ where $t$ is time, $C$ is capacity, $I$ is discharge current, and $k$ is the Peukert exponent.
- Final Runtime: Adjusted further by multiplying with Depth of Discharge (DoD), inverter efficiency factors, and temperature scaling coefficients.
How to Use This Calculator
- Input your battery's total amp-hours (Ah) or watt-hours (Wh) along with the nominal voltage.
- Specify your Peukert exponent depending on your battery type (e.g., Lead-Acid vs Lithium).
- Enter your active load requirements in Watts, Kilowatts, or Amperes.
- Adjust safety parameters such as Depth of Discharge (DoD) limits and system efficiency factors, then click calculate.
Frequently Asked Questions (FAQs)
Heavy discharge currents create higher internal resistance and chemical reaction bottlenecks, decreasing total available energy as described by Peukert's law.