To figure how many panels you need, calculate your daily energy consumption. Write down the power ratings of all the devices and the number of hours in use. Then multiply the power rating and hours for each device. Finally, sum the energy needs of every device together.
Solar panels perform at their maximum capacity only during peak sun hours. So, once you have the daily energy consumption of your boat, divide it by the number of peak sun hours in your region
. What you'll get as a result is the power of the solar array that you need. For more details, check out our detailed guide on calculating solar power
needed to travel the seas.
Don't go overboard with solar panels for your boat – you don't need too many, you need just enough. In residential systems, there is always something to do with excess energy from panels: you can sell it to the commercial grid, or even use it to charge your electric car
. Out in the open sea you will just throw away that surplus energy. So, with too many panels you may find yourself having spent more money than needed. Plus, extra panels take up space which is really valuable on a boat.