The energetic balance and the electric needs of sailboat

Electrical needs on cruising sailboat

The owners of cruising sailboat equip more and more their boat with a lot instruments in order to increase security and comfort on board (navigation instrument, communication, home appliance). The energy needs on sailboats are constantly increasing. The electrical production becomes therefore essential.

Energy balance of your sailboat

bilan électrique voilier

The energy balance is needed to dimension the batteries bank and to choose the needed equipments to produce the requiered electricity for daily on board consumption.

It is necessary to realise an inventory of electrical material, to check the operating power (Watt) for each device and to estimate the utilisation time for each equipment during 24 hours.

Example : for an equipment consuming 10 watt of power during 3 hours per day, the daily energy will be 30 Wh (10W x 3 hours).


Electricity consumption and navigation mode

The sailboat equipments and the necessary electricity vary according to the navigation mode.

The next tables show a synthesis of current equipments and their daily consumption depending of navigation mode.

Warning, these elements don’t replace a complete energy balance sheet of your sailboat


Daily navigation

For 10 hours of navigation, the average electricity comsumption is about 50 Ah, a daily need for 600 Wh with 12V batteries. Every evening the boat can be reload on dock power post at harbour.

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Coastal navigation with anchorage

The energy on board can become a problem because there is not recharging means as in daily navigation. There is a need of electrical autonomy.

The average electrical consumption for this navigation mode is 93Ah per 24 hours, this is corresponding at a daily need about 1000Wh with 12V batteries.

 consommation cotière GB


Offshore navigation

This mode of navigation requieres more important energy resources and electrical autonomy.

The average consumption for this navigation mode is 245Ah per 24 hours, this is corresponding at a daily need about 3.000 Wh with 12V batteries.

 consommation hauturiere GB


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 Source : « cahier spécial l’énergie à bord », BLOC MARINE 2017.