Solar panels are popping up everywhere, they are coming down in price and offer a lot of help to boaters. They provide power to batteries without having to run a generator or the engine. In the winter they trickle power in to the batteries. You will probably still need to run the engine or a generator to keep the batteries charged (but not as much as you would have if you didn’t have them). In the summer if you have enough they can provide for all your power needs and more. The autumn and spring are such that you will occasionally need to run the engine or a generator but there will be many days when it is sunny enough that you can do without them.
The solar panels on my boat
I currently have six solar panels on my boat. In the summer they provide more than enough power to supply all of my electrical needs when I am staying aboard (I don’t live on my boat yet so this is not a totally fair test). In the winter when I am staying aboard the solar panels provide enough power to power the lights and water pumps without me having to run the engine to charge the batteries or plug in to the electric point in my marina. In the winter I charge my phone away from the boat and don’t use the microwave. Also I use the fridge as a cupboard and keep milk in a bucket of cold water to keep it fresh in the winter.
Solar panels can’t connect directly to the batteries as the voltages that they work at are slightly different. They have to be connected via a controller. There are two different types of controller, MPPT controllers (which stands for Maximum Power Point Tracking), and PWM controllers (which stands for Pulse Width Modulation). Either one will charge up the batteries to the correct voltages but all the experts I have found say that the MPPT controller is better than the PWM controllers. The PWM controllers are cheaper than the MPPT controllers, but not by a huge amount.
Due to the fact that they have no moving parts solar panels are hard to break, they don’t wear down through excessive use, and importantly, they are silent workers. Solar panels just get on with the job of charging your batteries wherever you are and will pump in as much power as they can for the light level that they are in.
There are two different ways that you can have solar panel installed, one is to get a professional to do the job (what I did as I wanted a lot of solar power and I didn’t want it to break down, also I didn’t understand how it all worked when I first got it done). Or second is to buy everything and do it yourself.
If you are going down the do-it-yourself route I will give you a bit of help by explaining my system step by step. This is not meant to be a definitive guide as I am not a professional, please do all your own research before embarking on this very worthy project.
-Solar panels, you can choose any size type and wattage, for installation purposes there are two types, stick on panels and panels that are mounted on brackets. I imagine that the stick on panels would just stick on. If you have the bracket mounted ones then remember when drilling holes in the top of your boat to waterproof the holes that you are drilling for the screws with silicone or something so you don’t get leaks later.
-Cables, you need to transmit the power from the solar panels to the batteries via the charge controller and to do that you will need cables. For the outside as well as being large enough to carry the charge without significant voltage drop you will need to make sure that they are waterproofed as well as insulated.
-Charge controller, do your due diligence to make sure that the controller you pick will do the job that you need it to do. The best type is an MPPT controller. (Don’t just type PWM controller in to eBay as you will get several volume controls which are not suitable). If in doubt ask the person or company who are selling it. These are not cheap pieces of kit so make sure that you get it right.
This is my charge controller
-Cables, you will need more cables to connect the charge controller to the batteries, remember to connect the positive cable to one battery and the negative cable to the battery at the other end of your battery bank so that all the batteries are equally well charged.
-Battery bank, virtually all boats will have this already (maybe excepting sailaways), you just need to make sure that everything is connected properly and away you go.
Next step is to enjoy your free silent power.