1. What is Peukert's Law?

Peukert's Law describes how the capacity of a lead-acid battery changes with the rate of discharge. Batteries appear to have higher capacity when discharged slowly and lower capacity when discharged quickly.

2. How Does the Calculator Work?

The calculator uses Peukert's formula:

Where:

• \( Ah_{rated} \) — Rated battery capacity in amp-hours
• \( I \) — Discharge current in amps
• \( t \) — Discharge time in hours
• \( n \) — Peukert's exponent (typically 1.1-1.3 for lead-acid)

Explanation: The equation adjusts the rated capacity based on actual discharge conditions and the battery's Peukert exponent.

3. Importance of Adjusted Ah Rating

Details: The adjusted rating helps determine actual usable capacity under specific discharge conditions, crucial for proper battery sizing in applications.

4. Using the Calculator

Tips: Enter the battery's rated Ah, your expected discharge current and time, and the Peukert exponent (check battery specs or use 1.25 as default for lead-acid).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical Peukert exponent?
A: For lead-acid batteries, typically 1.1-1.3. Lithium batteries have exponents closer to 1.0 (less capacity loss at high currents).

Q2: Why does capacity change with discharge rate?
A: At higher currents, more energy is lost to internal resistance and chemical inefficiencies, reducing usable capacity.

Q3: How accurate is this calculation?
A: It provides a good estimate but actual performance depends on temperature, age, and specific battery chemistry.

Q4: Can I use this for lithium batteries?
A: Lithium batteries have much lower Peukert effects (n≈1.0-1.05), so the adjustment is often negligible.

Q5: Where can I find my battery's Peukert exponent?
A: Check manufacturer specifications or use typical values (1.25 for lead-acid, 1.05 for lithium).