Autopilot and Navigation Power Consumption
Estimate yacht autopilot, AIS, VHF, chartplotter, radar and navigation loads for offshore lithium battery planning.
Autopilot power is one of the most variable loads on a sailing yacht.
It depends on sea state, sail balance, boat speed, helm load, actuator type, rudder balance, course changes and point of sail.
A calm-water amp reading is not necessarily an offshore amp reading.
Passage energy audit
Measure or estimate:
- chartplotter
- instrument displays
- wind/depth/speed sensors
- AIS
- VHF
- radar
- autopilot computer
- drive unit
- satellite communications
- navigation laptop or tablet
A passage system should have reserve and redundancy because these are not optional hotel loads.
Turn the appliance into a daily energy figure
The peak wattage tells you whether the inverter and BMS can start the load. Runtime tells you what it does to the battery bank. Treat those as separate checks, then include conversion losses and the loads already running aboard.
- Measure typical watts and realistic hours per day, including standby use and cycling loads.
- Check startup surge and maximum simultaneous current against the inverter, BMS and cabling.
- Test the result against a poor-solar day and preserve a reserve for essential navigation and safety loads.
Work out your own numbers
Battery Runtime CalculatorCalculate how long a marine lithium battery bank will run a given load, down to the state of charge you are willing to reach.Marine Lithium Battery Size CalculatorWork out the lithium battery capacity your boat needs from daily kWh, reserve, autonomy, voltage and charging capability.
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