Thursday, December 4, 2014
Things on a boat are in a constant state of flux. By that I mean that a boat is always in need of maintenance and repair, in addition to the needed upgrades to electronics and improvements to systems. Our boat has nine batteries for example, and they need to be maintained at a proper level of charge or they will die a quick death. Nine batteries cost a lot of dough, imagine that. While at the dock, it is a simple process to keep them happy... just plug a big fat yellow power cord into the dock power, and our on-board battery charger takes care of business. Once we are out sailing though, it is a different story. Our power cord is only fifty feet long, so any long distance sailing requires a different solution. No, not a longer cord, the idea is to cut the cord. A sailboat has basically two options for this problem, a generator or a different source of 12 volt power. We have a generator, it runs on diesel, is kinda noisy, not too bad though, and generates 120 volt AC power that in turn powers the on-board battery charger. The other answer, is to install a source of power that does not use diesel and will still charge up those expensive batteries. A wind generator is one way to do this, and here in the dependable trade winds, the wind generator is a pretty decent option. They used to be pretty noisy, but the new ones I have seen around on other boats are really quiet. Imagine, a little wind and, BINGO you are up and running. The other popular option is to go with a solar system. Here in Florida, and in our future stomping grounds of the Bahamas and the Carribean, sunshine is in abundance, and we chose to go with solar. Solar charging really is a system of components engineered to work together, so that your boat's batteries are kept in the best possible state of charge. This requires the panels themselves, properly sized wiring between the panels, a charge controller, and breakers or fuses between the panels and this controller thing, and then between all this and the boats batteries. Properly mounting the panels so that they have air space beneath them is important, as they get hot in the sun, just like we do. We mounted our panels on a rail system, on our boats hardtop. This rail system really stiffened up the top, and our panels are about 2 inches above the top. The panels we chose are mono-crystaline 120 watt panels. There are 6 of them, so that is a lot of power for a boat system. We could have chosen poly-crystaline panels, they are only slightly less expensive these days, and the mono panels are supposed to be more efficient, especially on overcast days. Actually, solar has gotten so inexpensive these days, it is a really good option for boats, where everything is super expensive anyhow. Just several years ago, solar was four to five dollars per watt. So, an 80 watt panel was 350 or 400 bucks. Not so nowadays, decent panels can be found for less than 2 dollar a watt. What? No, watt . The charge controller is the smarts of the system, and because I wanted to do all this just one time, I got a good one. Our controller ls made by Morningstar, a leader in solar charging controllers. Our system should generate a peak of 720 Watts of power, and the charge controller will put a 50-60 amp charge at 12 volts into our nine batteries. That's a pretty healthy jolt of juice, like a triple, super, Cuban espresso in the Quart-to-go size. This should be able to power us back up in the morning, and then run our 12 volt water maker so that we can have so much water that we might have a free water fountain mounted on the back of the boat for passers by that need a quick drink. Probably not though. Get your own water maker. You can see the big black cables on the right of this picture, these come from the panels. They go straight into a box that has breakers inside. This is so the power can be disconnected from the system beyond here, in case something needs to be worked on. Our panels are 24 volt each, and three are wired together on each side of the boat for a total of 72 volts on each leg. These two 72 volt feeds go into this breaker box, and then out to the charge controller. It receives this charge and converts it into a 12 volt charge sending it to the batteries through another breaker to its left. This breaker is needed to isolate the whole system from the boats batteries in case of a needed repair. The power leaves the breaker and goes to the house batteries and then out to the other three batteries. All this trouble for a battery bank? Yep, it's the life of our boat. Once we are disconnected from shore, we are a 12 volt machine. We have an inverter aboard that takes 12 volts and turns it into 120 volt, to run the microwave oven and the television mostly. Our computer chargers are 120 volt too, as are some small items on the boat. But the work horse of the boat's electric system is the 12 volt batteries. Let's see... nine batteries, say 80 pounds each, that's 720 pounds of batteries. Yikes! That is like hauling around a piano, or a whale, or something else that weighs 720 pounds!