Typical Sailboat Energy Usage

Here we show the devices and how much energy you would typically use on a sailing boat on a sailing vacation each day.

* The inverter drainage is left out of the total since many boats do not have one. However, note that it is a large drain of power. It is called a parasitic drain because even when the inverter is not being used it is still draining that amount of power. Make sure you switch off the inverter when you are done using it. Left on for 24 hours, the amount of energy for nothing is 110 x 24 = 2.5kW.hrs. Meaning it will run your whole house system almost empty. BIG NOTE: turn off the inverter unless it is powering something essential.

With the typical house battery capacity of about 1500 watt.hrs, the above table means that 2 big batteries could not supply the energy you use in one day. Your fridge would shut down and your very annoying low-voltage alarm would turn on (if there is one).

What all of this really means is that as the manager of the boat, you must monitor very closely your energy usage, be cognizant of its depletion rate, and properly plan to top up your batteries with energy from available sources throughout the day.