Self-sufficient life | #2 Solar energy

12 Jan Self-sufficient life | #2 Solar energy

Posted at 05:41h in Self-sufficient life by Niels

To sail around the world in a self-sufficient manner, we must generate our own energy. We do this in various ways and make use of renewable energy sources. That means without the use of fossil fuels. One of the most important renewable energy sources is of course the sun. Solar panels are needed to use the energy from the sun. During the preparation, several questions quickly arose: “How many panels do we need in total?” And “What type of panels should they be and where do we place them?”

During Niels’ graduation project, it was investigated how many solar panels are needed to live on board. The conclusion was that it is not too bad how many panels you need. For a boat on which we live with 2 people, 600Wp will suffice. Of course it depends on how much energy you use and how long the sun shines. Because more and more technology is on board, and therefore more power consumers, we had estimated that we use 1 kW per day. After two years of sailing this appears to have been a wrong estimate. We cook electrically, work a lot on the computer and always have the fridge on. In the evening we often watch a movie and occasionally play a game on the Xbox. While sailing, our biggest energy consumer is the autopilot, which is on 90% of the time.

When purchasing the panels, we ultimately opted for flexible panels. We did this by placing 6 x 100Wp panels on the boat. Because some panels are in the shade during the day, we have added two more. Because the lithium batteries are 48V, we have placed the eight panels in two series of four. These series are then connected to each other in parallel. In this way we generate a high voltage (+ 60V), which goes via an MPPT controller (Maximum Power Point Tracking) from Victron to the 48V batteries. This works very well and we were very satisfied until …

… until after a few months of sailing we came further south and it became warmer. The teak deck of the New Nexus suffered a lot and became extremely hot during the afternoon. This has not had a good influence on the construction of the flexible panels on the teak deck. They became too hot and because there is a slight bend in the teak deck, there was too much tension in the adhesive layer. The panels let go and our generation capacity declined rapidly. We no longer exceeded 300W on sunny days. Self-sufficient life is of course quite difficult in this way. In Panama we eventually replaced part of the flexible panels with fixed panels. Ordinary panels that also lie on the roof of houses in the Netherlands (260Wp). There are two large panels hanging along the side of our ship, which we can adjust towards the sun. Both were connected to each other in series. We have generated a lot of energy with the panels throughout the Pacific and it works fantastic. The efficiency is high and because they have an air flow at the bottom, they cool a lot better. The result: We only generate around 1.5kW per day with these two panels.

Een geliefde plek voor de dagelijkse behoefte van boobies ( vogels ^^)

For the 12V part we have installed other panels on our own battery bank (AGM). This is a common voltage on boats and we thought it would be better to install a system of our own for this. We finally did this by placing three medium-sized (2x 200Wp and 1x 165Wp) solar panels on the ship. Two on top of our bimini hood and one on the back of the davits. We are very pleased with this. The best place is actually above the davits, because the boom sometimes wants to provide some shade above the bimini hood. We never really worry about the 12V, because it always charges more than the total 12V use on board.

To be able to sail electrically, we have to generate even more electricity than just for life on board. More about this in the article about electric sailing.

Do you want to know more about this subject or do you have questions? Send an email to info@4greenfoundation.com

Next week: Generate energy with the wind.