There are many factors involved in choosing solar panels for your yacht and we will try and share or experiences to ensure you make the right choice. The main factors to consider. 1 Your current battery bank capacity in amp/hrs 2 Your usable battery bank capacity (we use the 30% rule on our own yacht, ie: 30% of total capacity in amp/hrs) 3 Your daily usage requirements in amp/hrs, is this in line with 30% of total capacity? 4 The available space to fit solar panels on your yacht 5 The actual performance of the Solar Panels versus the manufacturers data 6 The climate and daily sunshine hours where your yacht will be sailing.
So a simple calclation might be as follows. (this is purely based on our experiences of living aboard in the Med and travelling back to the UK, please do your own research) we bought or Solar Panels from Bimble Solar who have an excellent solar power calculator and complete packages for cruising sailors at bimblesolar Current battery bank total capacity = 360 amps (lets use 12 volts) Multiply by the 30% rule = 108 useable amp/hrs per day Solar panels are now required to recharge the batteries with 108 amp/hrs per day. So we need 108 amp/hrs x 12 volts = 1296 Watts Lets assume we fitted 2 x 150 Watt Solar Panels = 300 Watts capacity In the UK we achieve 50% of manufacturers stated maximum performance so would expect the following: Winter hours in the UK = 5 x 300 watts = 1500 watts x 50% performance = 750 Watts. a shortfall of 396 Watts or 33 amp/hrs Summer hours in the UK = 8 x 300 watts x 60% performance = 1440 Watts a small surplus of 144 Watts or 12 amp/hrs Summer hours in Greece = 10 x 300 Watts x 70% performance = 2100 Watts a good surplus of 804 Watts or 67 Amp/hrs. Where can you fit Solar panels on your yacht