Electric Boat Range Calculator
Calculate range and runtime for electric boat propulsion systems based on battery capacity and motor specifications.
How to Use
- Enter your battery bank capacity in amp-hours (Ah)
- Enter system voltage (12V, 24V, 36V or 48V)
- Enter motor power draw at cruising speed in watts
- Motor efficiency defaults to 85% — adjust for your motor
- Enter your target cruising speed in knots
- Depth of discharge: 80% for lithium, 50% for lead-acid
Note: Actual range varies with wind, current, load and sea conditions. Plan with a 20% safety margin for real-world use.
Frequently Asked Questions
How far can an electric boat go on one charge?
Range depends on battery size, speed and motor efficiency. A typical setup with 200Ah lithium at 48V (9.6 kWh) running a 2kW motor at 4 knots gives roughly 4-5 hours runtime and 16-20 NM range.
Does speed affect electric boat range?
Dramatically. Power requirement increases roughly with the cube of speed. Doubling your speed from 3 to 6 knots can reduce range by 60-70%. Slow cruising maximises range on electric boats.
Lithium vs lead-acid for electric boat range?
Lithium (LiFePO4) gives 60-80% more usable range than the same Ah rating in lead-acid because you can safely use 80% depth of discharge vs 50%, and lithium maintains voltage better under load.