Watermaker Power and Marine Lithium Batteries
Calculate the energy required to run a yacht watermaker and integrate it with solar, lithium batteries and generator charging.
Compare watermakers using litres per hour, watts while operating, watt-hours per litre, startup current, operating pressure, freshwater flush consumption and DC versus AC power.
Energy efficiency metric
Wh per litre = operating watts / litres per hour
Example:
A 300W system producing 60L/h:
300 / 60 = 5Wh per litre
Producing 90L:
90 x 5 = 450Wh
A liveaboard with an electric galley, washing machine and frequent showers may increase both water demand and battery demand.
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.