1. What is the Battery Capacity Calculation?

The battery capacity calculation determines how many amp-hours (Ah) your 12V battery needs to power a trolling motor for a specified runtime, accounting for system efficiency.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• Motor Power — The wattage rating of your trolling motor
• Runtime — Desired hours of operation
• Efficiency — System efficiency factor (typically 0.7-0.9)
• 12 — Voltage of the battery system

Explanation: The equation converts watt-hours to amp-hours while accounting for voltage and system losses.

3. Importance of Proper Battery Sizing

Details: Correct battery sizing ensures sufficient runtime, prevents deep discharges that shorten battery life, and maintains optimal motor performance.

4. Using the Calculator

Tips: Enter motor power in watts, desired runtime in hours, and efficiency factor (default 0.85). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical efficiency factor?
A: Most systems are 70-90% efficient. Use 0.85 as a default unless you know your specific efficiency.

Q2: How do I find my motor's wattage?
A: Check the motor's specifications or calculate as: Watts = Volts × Amps (from motor rating).

Q3: Should I add a safety margin?
A: Yes, add 20-30% to the calculated value to account for battery aging and unexpected loads.

Q4: Can I use this for 24V systems?
A: No, this is for 12V only. For 24V, replace the 12 in the formula with 24.

Q5: How does temperature affect battery capacity?
A: Cold temperatures reduce available capacity - you may need 20-50% more capacity in cold weather.