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Battery Discharge Runtime & Capacity Calculator (Peukert's Law)

Peukert's law captures the non-linear reduction in deliverable amp-hour battery capacity caused by internal chemical resistance at elevated discharge currents.

Calculated Result
8.71 hours

Estimated Runtime

Delivered Capacity

87.06 Ah

Effective Capacity Utilization

87.1%

Peukert Exponent (k)

1.2

Calculation Breakdown

  1. Calculate discharge duration using Peukert's empirical lawt = H * [C / (I * H)]^k = 20 * [100 / (10 * 20)]^1.2 = 8.71 hrs
  2. Calculate effective delivered charge capacityC_{eff} = I * t = 10 * 8.71 = 87.06 Ah

Discharge Current vs Effective Capacity

Interactive visualization based on your current inputs

Capacity
0.02550751005 A (0.05C)10 A (0.1C)25 A (0.25C)50 A (0.5C)Current (A)Effective Capacity (Ah)

What Is the Battery Discharge Runtime & Capacity Calculator (Peukert's Law)?

Peukert's law captures the non-linear reduction in deliverable amp-hour battery capacity caused by internal chemical resistance at elevated discharge currents.

How Does the Battery Discharge Runtime & Capacity Calculator (Peukert's Law) Work?

The calculation evaluates user-provided measurements using recognized domain equations, converts between measurement units, and adjusts for real-world efficiency factors.

Battery Discharge Runtime & Capacity Calculator (Peukert's Law) Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

t = H \cdot \left[\frac{C}{I \cdot H}\right]^k

Where H is rated rating hours (typically 20 hours for lead-acid), C is rated Ah, I is load current, and k is the Peukert constant (1.1 - 1.3).

How to Use the Battery Discharge Runtime & Capacity Calculator (Peukert's Law)

  1. Enter your primary measurements in the input fields above.
  2. Select your preferred units (e.g. metric or imperial) if applicable.
  3. Review or adjust operational assumptions such as field efficiency.
  4. Click Calculate to instantly generate the full results breakdown and visual chart.
  5. Use the Reset button at any time to clear the form and test a new scenario.

Step-by-Step Example Calculation

100Ah Battery at 10A Load

Input Values:

ratedCapacityAh:100
ratedHoursH:20
dischargeCurrentA:10
peukertExponentK:1.2

Understanding Your Result

Your calculated result represents the realistic operational capacity or baseline output under the specified conditions. Comparing theoretical and effective outputs reveals the direct impact of turns, overlap, and practical downtime.

Factors That Affect the Result

Field terrain, operator experience, equipment maintenance, overlap margin, and weather conditions can significantly influence real-world output.

When Should You Use This Calculator?

Use this calculator whenever you need quick, verified estimates for job planning, budgeting, equipment sizing, or project timelines.

Assumptions & Limitations

  • Ensure consistent unit dimensions when specifying engineering input parameters.

Frequently Asked Questions

Calculation Accuracy & Reference Note

This calculator implements verified, deterministic mathematical equations based on published standards. Results should be treated as professional engineering estimates; always verify critical operations with local equipment manuals and site inspections.

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