1. What is Battery Amp-hour (Ah) Capacity?

Amp-hour (Ah) is a unit of electric charge that represents how much current a battery can supply over time. A 12V battery with 100Ah capacity can theoretically deliver 5 amps for 20 hours, or 20 amps for 5 hours before being fully discharged.

2. How Does the Calculator Work?

The calculator uses the basic formula:

Where:

• \( Ah \) — Amp-hour capacity
• \( Wh \) — Watt-hours (energy capacity)
• \( V \) — Voltage (12V for most lead-acid batteries)

Explanation: This formula converts energy capacity (Wh) to charge capacity (Ah) by dividing by the battery voltage.

3. Importance of Battery Capacity Calculation

Details: Knowing your battery's Ah capacity helps determine how long it can power your devices, size your solar power system appropriately, and compare different battery options.

4. Using the Calculator

Tips: Enter the battery's watt-hour rating (often found on the label) and its nominal voltage (12V for most lead-acid batteries). The calculator will determine the Ah capacity.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between Wh and Ah?
A: Wh measures energy capacity (power × time), while Ah measures charge capacity (current × time). Wh accounts for voltage differences between batteries.

Q2: How long will my battery last?
A: Divide Ah by your device's current draw in amps. A 100Ah battery powering a 5A device would theoretically last about 20 hours (100Ah ÷ 5A = 20h).

Q3: Can I use this for lithium batteries?
A: Yes, but lithium batteries often have different voltage profiles (e.g., 12.8V nominal for LiFePO4). Use the battery's nominal voltage for calculation.

Q4: Why is my actual runtime less than calculated?
A: Real-world factors like temperature, discharge rate, battery age, and depth of discharge limitations affect actual performance.

Q5: How do I convert Ah to Wh?
A: Multiply Ah by voltage. A 100Ah 12V battery has 1200Wh capacity (100Ah × 12V = 1200Wh).