Australia is a hot and sunny country, nothing new there. But when you really absorb that fact it is pretty easy to see that solar-powered campsites make more sense than a cold beer on a hot day. The luxury of bringing more electrical items from home to further enjoy your stay, and the fact you can settle into one spot for a few days, are the key reasons folks investigate solar. And I’m not here to say that’s a bad idea at all! What I am opposed to, though, is not getting the most of these bulky and often expensive 12V charging systems. So let’s put an end to that, with these seven pearls of wisdom guaranteed to transform you from gumby-to-guru on all things solar.
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SO, HOW DO THEY WORK?
Solar panels are constructed from layers of silicon linked in either series or parallel… or both. This then creates what is known as a solar module. Anti- reflective layers are applied, and then everything is connected with silver paste which is screen-printed and then essentially ‘cooked’ to secure all components together. Cool, hey! Solar panels absorb sunlight into something known as photovoltaic material, which translates in simple terms to light electricity. While absorbing energy through the panel, electrons are knocked loose – allowing the electrons to pass through the panel, in turn creating electricity. This is the simplified version of the story, but it sure beats flying a key on a wet string in an electrical storm to charge your Kindle in an effort to read the latest Harry Potter.
Okay, this is where things start to get a bit technical. So bear with me here. After speaking with our friends at Redarc, they mentioned there are two main types of solar panels: Amorphous and Crystalline. The latter refers to Monocrystalline and Polycrystalline solar panels. Okay, have you prepared for impending technical overload?
Amorphous solar panels are the newer kids on the block here, and are composed of silicon in a non-crystalline random form. The benefit is they can be laid onto many different surfaces to allow for flexibility (such as solar blankets, which we will touch on shortly). According to Redarc, these thin-film solar panels have an efficiency of approximately 6-7%; are much lighter; and, as they fold up ridiculously small, are much easier to store and transport. Crystalline Silicon solar panels are also created from silicon (are you ready for it?) but are set in a tetrahedral lattice type structure. Apparently, this structure actually allows for a more efficient solar panel, with higher efficiency per square metre over an amorphous solar panel. Still with us?
SOLAR BLANKETS FOR COLD BATTERIES
Folding solar blankets, or amorphous solar panels, are all the rage these days; and considering how much easier they are to travel with compared to rigid folding panels, nobody is surprised. They are lighter, and physically smaller when folded into their carry pouches. And while this is a real asset to anyone on the road, typically speaking amorphous panels aren’t as efficient as rigid panels pound for pound. They are also (for the most part) more expensive to purchase. However as technology trickles down both of these points will no doubt change. If you have a bad back, or are lacking storage space, this new(ish) technology is a godsend. On a practical note, a solar blanket can be draped over the windscreen keeping the vehicle’s interior cooler. Just remember to tie or peg them down… as an amorphous solar panel would make a very expensive kite.
Typically, the battery in your 4X4 needs around 13.6V for it to charge. Now, if you were to connect a solar panel directly to your battery on a sunny day, there is potential for the panel to output much more than that figure – catastrophically damaging the battery internals. For solar panels to work safely and effectively, a clever device called a ‘regulator’ needs to be used in-line. Basically, a solar panel regulator will accept whatever power the solar panel is producing via the sun, and limit the output figure to within a safe tolerance for the charge required by the battery. Many solar panels have in-built regulators; however on cheaper panels their effectiveness is questionable. The two main varieties of regulators available are known as Pulse Width Modulation (PWM) or Maximum Power Point Tracking (MPPT). MPPT regulators are more expensive, but they offer a few key advantages such as preventing reverse current flow at night. If you are shopping around for a new panel, ask about the features of the included regulator before letting those moths fly out of your wallet.
STARE AT THE SUN… NOT THE SKY
No, I’m not talking about with your eyes; that would be terrible advice. With your solar panel, my friend! Correct positioning of a solar panel will provide the best bang-for-buck upgrade you will ever get out of a 12V charging system. Prime example: You set up camp in a valley under some trees. At midday, your panel might be receiving plenty of sun-juice; but once the sun starts to set the panel could be partially resting in shade and now not working to anywhere near full potential. The panel should be exposed to as much sunlight as possible at all times. As this is not always easy, the 12V experts at Redarc tell us the correct answer is to position your panel on a 45-degree angle whilst facing north. Maybe they should start building compasses into solar panels (patent pending… I came up with it first?).
Much like your favourite pair of boots, solar panels don’t require too much maintenance. Having said that, the small amounts of love they do require are critical to their operation. The main bit of work which will enhance the operation is a simple clean after (or before) each use. What I personally do on my own 120W solar panel is use two microfibre cloths to wipe it down after each trip, as these won’t scratch the surface. One is put under a warm tap at home, and the other is used to dry the panel after a bit of a scrub. If there is a layer of dirt and crud on top of the panel it can’t be expected to absorb the sun’s energy, can it? Apart from that, a regular check of the supplied wiring is advised to ensure it hasn’t been damaged. Also, don’t be afraid to tighten any screws or bolts (if you have a rigid solar panel) from time to time. This will keep everything operating as expected in the heat of the moment (yes, that was a very bad joke).
TOO MUCH SOLAR?
To be blunt, no you can’t have too much solar. Well, you could be bringing away more than you need – but as long as there is a quality regulator used there is no reason why your battery would sustain damage. The big question then is: How much do you need? Well, this all depends on how much current you are drawing. Many four-wheel drivers will have at least one fridge/freezer, and a few LED camp lights that need powering. Let’s say the fridge draws 3.0 amps per hour (AH), and the LED lights draw 0.5 amps per hour. If you run them both for 24 hours, that is 84 amps per day you are using (I know, who uses lights during the day, but I’m terrible at maths). If you have eight hours of direct sunlight per day, let’s do a few sums. 85AH x 12V = 1,008WH (watts per hour) 1,008WH 8H = 126W The advice we received suggested that it’s a wise call to overrate your expectations by 20% – so for this particular case study a 150W solar panel would be the logical choice.