1. What is the 12V Battery Run Time Calculator?

This calculator estimates how long a 12V battery will last powering a specific load. It's useful for planning power systems, RV/camping setups, and emergency backup systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Battery Capacity — The amp-hour rating of your battery
• 12V — Standard voltage for lead-acid batteries
• Load Power — The wattage of the device being powered

Explanation: The formula converts battery capacity to watt-hours (Ah × V = Wh) then divides by load power to get runtime in hours.

3. Importance of Run Time Calculation

Details: Accurate runtime estimation helps prevent power outages, ensures proper system sizing, and extends battery life by avoiding deep discharges.

4. Using the Calculator

Tips: Enter battery capacity in amp-hours (Ah) and load power in watts (W). For multiple devices, sum their wattages. Consider adding 20-30% buffer for real-world conditions.

5. Frequently Asked Questions (FAQ)

Q1: Does this work for lithium batteries?
A: Yes, but lithium batteries often have more usable capacity than lead-acid (can discharge deeper without damage).

Q2: What affects real-world runtime?
A: Temperature, battery age, discharge rate, and inverter efficiency (if converting to AC) all impact actual runtime.

Q3: How accurate is this calculation?
A: It provides theoretical maximum. Real runtime is typically 10-30% less due to efficiency losses and other factors.

Q4: What about battery banks?
A: For multiple batteries in parallel, sum their Ah ratings. In series, voltage increases but Ah stays the same.

Q5: Should I fully discharge my battery?
A: No. Lead-acid batteries should typically not be discharged below 50% capacity for longest life.