1. What is the 100Ah Battery Run Time Calculation?

This calculator estimates how long a 100 amp-hour (Ah) lithium battery will last powering a specific load, considering battery voltage and system efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• 100 — Battery capacity in amp-hours (Ah)
• Battery Voltage — Nominal voltage of battery bank (e.g., 12V, 24V, 48V)
• Efficiency — System efficiency factor (typically 0.85-0.95 for lithium)
• Load Power — Power consumption of connected devices in watts

Explanation: The formula converts battery capacity to watt-hours (Ah × V), applies efficiency loss, then divides by load power to get runtime.

3. Importance of Run Time Calculation

Details: Accurate runtime estimation helps in sizing battery banks for solar systems, RVs, marine applications, and backup power systems.

4. Using the Calculator

Tips: Enter battery voltage (typically 12V, 24V or 48V), efficiency (0.85 for conservative estimate), and load power in watts. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why use 85% efficiency for lithium batteries?
A: While lithium batteries themselves are 95-98% efficient, system losses from wiring, inverters, and other components typically result in 85-90% overall efficiency.

Q2: Can I use this for lead-acid batteries?
A: Yes, but use lower efficiency (0.5-0.75) and don't discharge below 50% capacity for longest battery life.

Q3: How does temperature affect runtime?
A: Lithium batteries lose capacity in extreme cold. Below freezing, capacity can be reduced by 20-30%.

Q4: What if my load varies?
A: For variable loads, calculate average power consumption or do separate calculations for different load levels.

Q5: Should I include inverter losses?
A: Yes, if using an inverter, either include its efficiency in the overall efficiency factor or multiply load power by 1.1 (for 90% efficient inverter).