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DC Cable Information

  You may note that DC cables are different than larger AC/DC Cables, in that there are two cables, a positive and negative. AC/DC cables have three. Positive, Neutral and Ground. The protocols of current carried by cables are based on science, and are complex, and I would not pretend to have knowledge enough to attempt explanations. All products sold by iShaja, are intended as mobile solutions. We do not sell, nor recommend permanently installed solutions; that is the domain of professionals and rightly so. The point of our cable selection is to provide a complete mobile solution, including cables and connectors, this, to save you from going shop to shop looking for single items and having to buy a packet of twenty lugs when you need only two.   As such, based on the output of the solar solutions, we offer a choice of cables, including connectors, and terminals depending on the parameters you request. These parameters include amp output of the panels, and the length of cable you choose, based on 12V batteries only. The cables we provide are multi-strand copper, with a connector, such as a spade lug, to slot onto your battery terminal. Where the cable is bare, we solder the tip, to keep the strands optimal for conducting current. The calculation we use for the choices offered are based on a calculator you will find at the link below. I find this site, 12 Volt Planet very informative. Connecting DC cables correctly always red to red. Sometimes, the “negative” cable may be white or black, but when you see any red – that goes to the red terminal or cable. Don’t be confused when you see both terminals at the end of your cable is blue, or red. The colours of the terminals are coded for the size of the cable, so rather be guided by the actual cable colour. Stay safe. Anne

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Introduction to Photovoltaic Panels (Solar Panels)

  This is a very brief overview of photovoltaic panels. I do urge you to read more detail, and here is a link to start you on your journey of understanding. There are typically Polycrystalline and Monocrystalline panels. All PV’s we supply are monocrystalline, as it has the most efficient conversion rate. The conversion rate for our PV’s is equal to, or greater than 21%. This conversion rate is an indication of the panel’s ability to convert sunlight into power. In other words, about 21% of sunlight captured is converted into energy. Polycrystalline panels have a lower conversion rate. One should consider placement of the PV’s. Behind glass, PV’s cannot reach their maximum efficiency, as glass reflects light, which means less light reaches the PV. Partial shade shall also affect efficiency, as does cloud cover. It may sound counterintuitive but heat also diminishes the efficacy of PV’s. One would find in the heat of summer, the PV is less efficient than a sunny winter day. Optimal temperature is around 25° C. When using our USB ports, bear in mind that the temperature of the battery in the device being charged also has bearing on efficiency. A phone in a hot car, would not charge efficiently. This is the reason why we suggest the use of a longer cable, so that whilst the PV is in the sun, one can keep one’s device in the shade. It can be tricky to find the perfect position for your PV and your device, as the length of the USB cable also affects the efficiency of current. I shall add another blog about USB cables, as that is also a complex subject. This is not a physics class and I do not pretend to be an expert. My wish is merely to create an interest in the hope that you shall do more research and reading on the matter, but, as a starting point, I shall try to show some examples that may help you understand solar panels, and aid you in selecting the right option to suit your needs and your budget. Watts – potential power is considered in watts. So, a 60W panel does not provide 60W when in the box, but it has the potential, when placed in perfect conditions, to generate 60W of power. In a formula, it would be denoted as (P) Volts – the force at which the generated power is transmitted, is referred to as Volts. (V) Amps – the speed at which power is transferred, is measured in amps. (A) When there is no load connected, there is no flow of current. But when a load (e.g. your cell phone) is connected, current flows, and in a formula is denoted as (i). Why i? From the French phrase intensité du courant, (current intensity). Take, for example, our 75W mobile PV, the voltage is 18V. It can transfer current at 4.2A. The formula is: P = V x i.      So, 18 x 4.2 = 75.6  – and there you have your 75W panel! Should you wish to charge a battery, let’s assume a Sealed Lead Acid Battery (SLA). The battery is usually 12V (24V is not used in this example). The capacity of the battery is denoted as Amp Hours (ah). The general rule of thumb, is that the charger (panel) should have the capacity to transfer current at rate at least 20% of the battery ah. Let’s assume you have a 12V – 20ah battery. You would require at panel that can generate a flow of current at least 4A (which is our 75W option. I shall do a separate blog on batteries. You will note that I do not yet have batteries for sale. I am investigating solutions and hope, soon, to have batteries available. Be Safe. Anne

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An Introduction To iShaja

  I was asked how it came about that I set up an online store selling photovoltaic panels. There is no short answer. Rather, this was, for me, a journey of discovery. If you know what you need, or want to skip straight to the technical stuff, please move on to the relevant detail. If you’re intrigued, read on. During one of our endless electricity blackouts, on day three, with all devices empty of charge, data depleted, I had gone through all the emotions of mourning the loss of connectivity to the world. The lost hours of work. Time on my hands and couldn’t get to the end of my audio-book. My friend popped over and asked if he could assist with charging my battery. My inverter is connected to the grid, not solar powered, and was long dead. He trundled back, carrying a heavy panel and mumbled what sounded like “what what”. I agreed whole-heartedly that Eskom was a disaster and what what. No. He was trying to explain to me that his panel was however many watts. The size of it. The amount of power it was able to unleash. Really. Next thing there were wires and clips and meters and what what. And so started my questions about all this intrigue unfolding before me. My friend tried his best to explain to me. Me, who had several decades ago bunked high school science and math classes. He became exasperated, said he was going out to mates, and left me with all this paraphernalia and a challenge. Anne, he said, if you can read, you can learn. I started reading. And learning. And questioning. Now, fascinated, at the first opportunity I bought a small solar panel. 10 watts. Surely it could do something, right? Once home, I opened the box, and there was the panel, with a 10cm wire, which branched into black and a red smaller wires, at the end of which was a black and red crocodile clip. Now what? I asked the local hardware store what to do next. I was told that the panel connects to a battery. No, they did not sell batteries. At the hardware store down the road, I was told that one should never connect a panel directly to a battery, a solar charge controller should be connected in between the panel and the battery. No, they did not sell solar charge controllers, nor batteries. How would I connect wires? Use tape. No, that doesn’t sound safe. Well, here are terminals that you need to crimp. But that’s packet of 20 – I only need 2. Sorry we don’t sell them loose. I eventually got what I needed. In abundance. And I did learn, and experiment, and question, and experiment again. I learned that wires are cables. That cables come in various sizes, specific to various parameters. That cables are not connected with tape. There are lugs and ferrules and soldering and heat-shrink tubing, and a myriad of solutions. Many calls were made to many electricians. I spoke to some, left messages for others, in an attempt to get professional input. I’ve not had a response from any. I indicated that I wanted information for small solutions, to provide power to charge cell phones, tablets, 12V batteries, inexpensive options for lighting. No response. Perhaps the industry is inundated with call-outs considering our the realities of our national grid. Perhaps there is too much work on the big stuff – big installations. Then came to mind the many folk not able to install a full home solar installation. About the many folk not able to afford a battery and inverter. What about the generation at school, how do learners study? And, what about the millions without any electricity supply. About the millions relying on paraffin lamps, and all the dangers and horror stories associated with paraffin accidents. How do folks living in cities communicate with loved ones in rural areas if a phone battery can’t be charged? And here I am, privileged, with a line of communication open, and I can’t get any assistance on finding an inexpensive solution. I have several decades of experience in international logistics. International trade. It is in my blood. It is the same passion, be it arranging a shipment of 25 kgs, or a 300 tonne project on a charter ship, to move cargo from a building yard or factory, anywhere in the world, to its final destination somewhere else in the world. I have used that knowledge to source solutions. To marry my life-long love of international freight, to my new- found intrigue with portable power. To offer, in a one-stop shop, everything needed for a small solution; from a small photovoltaic panel, to cables, soldering, or connecting, to lighting solutions. These solutions are small. They do not take the place of a full electrical installation. They are mobile. They are a stop-gap. They are convenient. They should never be wired to your distribution board. They should ALWAYS be handled with care. When in doubt, call your local electrician. Before you finalize any purchase from my shop, I urge you to refer to my Information Station. Consider what your requirements are, refer to the information provided, and decide on a solution. Should you want more information, please send an email, or WhatsApp. I’ll do my best to reply within a day. And, if you’re as intrigued as I am with this wonder that is power, that is energy, I will search for answers, and continually add content to the Information Station. Where I find easy to understand guides on “how to”, I’ll share links. If you are an expert in the field of solar, or electronics, or electricity, and are willing to share knowledge, please reach out to me. Be safe. Anne

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