Copyright 2017 - Kustom Power - ISBN#: 978-0-692-68208-1 Table of Contents Some of Your Questions Building Your Solar Wizard Testing Your Solar Wizard Upgrading Your Solar Wizard Some of Your Questions A good way to become familiar with the Solar Wizard is to peruse the following Pictorial, and then take a look at some of the questions that I’m asked most often. You can find the answers to a few of those most frequently asked questions here. What is the Solar Wizard? The Solar Wizard is a highly efficient electric power generator that produces electricity directly from the energy of the sun's rays. Since these rays are an inexhaustible and free source of energy, the Solar Wizard produces totally (100%) FREE electricity - and lots of it! Is the Solar Wizard expensive? Not at all! The entire concept of the Solar Wizard is based upon economy and simplicity. By following the easy step-by-step and illustrated plans and procedures of this manual, you can custom build your Solar Wizard to suit your own needs as well as your budget. By being creative, you can build a basic, but complete, system for as little as $200! From there you can readily build upon and expand your basic system as time and money allows. There's really no limit to the power generating capacity of the Solar Wizard. Every dollar invested in your Solar Wizard will eventually be returned to you many times over as FREE ELECTRICITY! Is the Solar Wizard reliable? The Solar Wizard is totally (100%) reliable. That's because of its totally (100%) solid-state electronic construction. With no moving parts to fail or wear out, the Solar Wizard provides many years of dependable, low-maintenance operation. All that's ever required is monthly cleaning of it's transparent cover to keep it working at peak efficiency. Nothing could be easier or more trouble-free! What all will my Solar Wizard power? The Solar Wizard will supply free electrical power for most home appliances, electronic devices, and lighting fixtures. However, as with all solar generators, it does have some limitations. Homes heated by electricity, whether by furnace or baseboard heaters, consume huge amounts of electricity, more than can be provided by even the largest home solar generators. In such situations it's best to supplement electric heat with a solar heating unit such as our "Sol-Air" and "Cozy Wizard" Solar Power Systems The Solar Cell The "heart" of every solar power system, regardless of its size or complexity, is the solar cell. What makes this incredible device unique is its ability to produce electricity when exposed to sunlight. Most solar cells are manufactured from materials similar to those used for electronic components such as transistors and integrated circuits. Solar cells are extremely reliable, but also fragile (almost paper-thin) and must be handled carefully to prevent damage. The Solar Cell Figure 1 When exposed to sunlight a single solar cell produces about 1/2-volt DC (Direct Current). While this is a very low voltage, it's a simple matter to connect several cells in series so that their individual voltages add on to one another. For example, by connecting 36 cells in series, about 18-volts DC will be generated. When connected to an electronic device (an inverter) 18-volts DC is converted to 115-volts AC (Alternating Current), which is a totally useful and practical voltage level for most home installations. Solar cells are manufactured in every size and shape imaginable, from square to round and everything in between. Regardless of its size or shape, every solar cell produces about 1/2-volt DC. In general, the greater the surface area of any cell, the more sunlight it is capable of absorbing - and therefore, the greater is its power generating capacity. A Complete Solar-Power System! In its simplest form, as shown in the following Figure 2, a complete solar power system consists of only two things: a single solar cell connected directly to a very low voltage (1/2-volt DC) device such as a flashlight bulb. As long as enough of the sun's rays are absorbed by the solar cell, the bulb will remain lighted. Other than to demonstrate the electric generating property of a single solar cell, such a system obviously has little practical use. A Complete Solar-Power System! Figure 2 When a solar cell absorbs sunlight it operates like an ordinary battery. Connecting cells in series (with the positive (+) terminal of each cell connected to the negative (-) terminal of the following cell) the individual voltages keep adding up, as shown in the following Figure 3. Since each solar cell generates 1/2-VDC (1/2- volt Direct Current), every second cell in a series string adds an additional 1-VDC. Thus, by connecting a total of 36 cells in series, an output of 18-VDC is generated. This is an ideal voltage level for powering the Solar Wizard inverter, allowing it to convert 18-VDC into 115-VAC (115-volts Alternating Current) of useful household power. Solar Cells - 36 Cell Series Figure 3 Purchasing solar cells as individual cells is usually the most economical way to go. However, they are also available as pre-wired "modules" arranged in various configurations. The Solar Array The module shown in the following Figure 4 contains twelve cells, capable of producing 6-VDC. Three 6- VDC modules (36 cells) connected in series will provide 18-VDC, which is the exact voltage required for the Solar Wizard. By arranging multiple modules, an "array" can be configured. This array contains twelve 6-VDC modules (144 individual cells). The Solar Array Figure 4 The modules in such an array can be interconnected to provide a wide range of voltage and power combinations. Solar Cell Power One of the most important things to consider when building a solar power system is its power output, always expressed in watts. You can build the Solar Wizard to provide any practical power level from 100 to 1,000 watts (even higher if desired). System and component costs will, of course, increase if greater power is desired. But, even relatively small systems (100 watts for example) can supply adequate power for many household appliances and devices. I recommend starting out with a small system because of its simplicity and low cost. You can always boost system power later if so desired. Solar cell capacity is rated by either power output (expressed in watts) or by current produced (expressed in amperes). If expressed in amperes, simply multiply current times voltage (1/2-volt average) to determine individual cell power. Thus, an 8 ampere cell produces 4 watts of power (8 amperes x 1/2-volt). To determine total system power, add up the power produced by all the cells. Thus, a 36-cell system such as the Solar Wizard, when equipped with 4 watt cells, will produce 144 watts (36 cells x 4 watts) - more than adequate power for a relatively small system. However, no power system (including solar power systems) can operate at 100% efficiency. Every system component produces some heat, which is wasted power. The Solar Wizard operates at 85% to 90% efficiency - most of the 10% to 15% power loss occurs in the form of heat dissipated by the inverter. So, for all practical purposes, your Solar Wizard system with 4 watt cells can be expected to provide anywhere from 122 to 130 watts of useable home power. Locating Solar Cells The first thing to do before building your Solar Wizard is to buy the necessary solar cells. The physical dimensions of your cell module or array will be dictated by the dimensions of the individual cells. Locating the best sources for solar cells will be time well spent since prices can vary wildly. Lots of bargains are out there if you're patient and willing to do your research. So, do some shopping around - you'll be amazed at what's out there since solar power is such an "in demand" technology. In general, I've found one of the best solar cell sources to be eBay - the selections and bargains there are incredible, especially if you're willing to accept cells that are less than perfect. Obviously you wouldn't want to buy damaged cells, but cells with minor flaws such as small scratches and chips work just fine, and they can be very economical. You can even find kits for repairing cell scratches to restore less-than- perfect cells to like-new condition. Often you can save lots of money by buying low capacity cells, which are more likely to be offered at bargains prices, and then connect them in parallel to obtain the desired power. Let's say, for example, that you locate 2-watt cells at bargain prices. A 2-watt string of 36 cells will generate around 61-watts to 65- watts of useable power. Since this power level is a bit on the low side, you could connect another 2-watt string of 36 cells in parallel to double the power (122-watts to 130-watts). An example of two 36 cell strings connected in parallel is shown in the following Figure 5. Actually there's no real limit, other than your time and budget restrictions, to the power generating capacity of your Solar Wizard system. Just by connecting additional 36-cell strings in parallel, you can customize it to match your exact power needs. You can even add 36-cell power strings with different power levels in parallel (for example, 36-cell, 4-watt cells in parallel with 36-cell, 3-watt cells). The Solar Wizard is designed to be the ultimate in simplicity and economy! CAUTION: When adding additional 36-cell strings in parallel, be sure all cells in each string are of equal wattage, and number exactly 36 cells, as shown in the following Figure 5. Failure to abide by this simple rule will cause system failures and malfunctions, and could permanently damage your Solar Wizard. Solar Cells - 36 Cell “String” Figure 5 Solar cells are sometimes offered in "sandwiched" layers secured with melted wax - the idea being to help protect them against shipping and handling damage due to their fragile nature. Some of the best cell bargains to be found are wax protected, but removing the wax can be a frustrating experience. I recommend purchasing a few more cells than actually needed since there's a good chance some cells will be damaged during wax removal. Note: The following procedure applies only to cells purchased in "sandwiched" layers secured with melted wax. CAUTION: Be sure to immerse the cells only in room-temperature water before heating. Immersing cold cells in hot water can destroy them because of thermal shock. Be careful not to heat the water to its boiling point. The violent action of boiling water can damage or destroy the cells. I've found the best way to remove the wax (perhaps the only practical way) is by melting it off with heated water. Fill a bucket or large pan with room-temperature water and fully immerse the cells. Turn on the heat, and heat the water as close as possible to, but just below, its boiling point. Allow the cells to "cook" until you feel certain that all the wax has melted. Carefully remove the cells and lay them on an absorbent cloth. Discard the water/wax mix, clean up the mess, and wait for the cells to cool to room-temperature. Repeat the cell "cooking" process to assure that as much wax as possible has been removed. WARNING: CARBON TETRACHLORIDE IS A TOXIC AND HAZARDOUS SOLVENT. BE SURE TO OBSERVE ALL SAFETY AND HANDLING PRECAUTIONS IN ITS USE AND USE ONLY IN A WELL VENTILATED AREA. To assure that all wax residue has been removed from the solar cells, I recommend carefully cleaning their entire surfaces with a soft clean cloth dampened with carbon tetrachloride (carbon tet). It's the only solvent I'm aware of that will dissolve wax, and is available at chemical supply stores. Be sure to wear protective rubber gloves since carbon tet can be absorbed directly into the bloodstream through the skin. Note: Since the Solar Wizard is custom-built according to your desired power output, its components must be carefully chosen to match that power capacity. After determining the power output desired from your Solar Wizard, and purchasing the needed solar cells, you will then be in a good position to choose the correct components and to actually start construction.. Note: The Solar Wizard system Pictorial is presented here. To do the best job of obtaining high quality components, and at the most economical prices, you should fully understand system operation. The following series of block diagrams and descriptions are designed to "lead you by the hand" - to guarantee your success and assure the best possible performance from your Solar Wizard. Actual construction starts in the “Building Your Solar Wizard” section. The Block Diagrams To obtain peak performance and efficiency from your Solar Wizard, you should familiarize yourself with its basic operating characteristics - all of which are easy to understand. The following block diagrams and descriptions are presented just for that purpose - don't overlook them. All solar electric power systems operate according to the same basic principals regardless of their size or complexity, and the Solar Wizard is no exception. Once you learn how the Solar Wizard functions you will be able to make wise decisions when it comes time to choose the best system components at the most economical prices. In short, the more you know about the Solar Wizard, the more time and money you will be able to save while building it - not to mention the satisfaction you'll gain from a perfectly operating Solar Wizard! Most Basic Block Diagram Block diagrams simplify the learning process by presenting a visual image of a system in its most basic form. Referring to Figure 2, the following Figure 6 is its equivalent presentation as a simple Block Diagram - a basic, yet complete, solar system. The system power source is a single Solar Cell that generates only 1/2-Volt Direct Current (1/2-VDC), and is connected to a Load, in this case a very low voltage Flashlight Bulb. Basic System Block Diagram Figure 6 As long as sunlight is being absorbed by the solar cell, the bulb will remain lighted. The Load could be any low-voltage electrical device, such as a miniature motor or electronic calculator. Such a simple system has little practical use, other than to demonstrate the electric generating property of a solar cell. Practical System Block Diagram By going a step beyond the most basic system, we arrive at a practical system powered by a Solar Module or Array, as depicted in the following Figure 7 - which is the power source of the Solar Wizard. A Solar Module consists of 36 solar cells (1/2-VDC each) connected in series to generate 18-VDC. If we desire higher output power (greater wattage), we can keep adding any number of Solar Modules (connected in parallel) to create our Solar Wizard Array. Practical System Block Diagram Figure 7 Many appliances are specifically designed to operate directly from low-voltage DC systems, mainly because of the growing popularity of Recreational Vehicles (RV's), and remotely located homes and cabins not connected to a commercial power grid. But, they are all specialized appliances and tools and, as such, can be quite expensive. The most obvious drawback to such a system is that it's only useful while the sun is shining. Adding a Storage Battery We can dramatically increase the flexibility and usefulness of our Solar Wizard simply by adding a Storage Battery, as depicted in the following Block Diagram of Figure 8. Now, in addition to the Solar Module or Array powering DC Loads, the battery will be directly charged during hours of sunshine, allowing it to supply 12-VDC power after the sun goes down. Such a system is totally functional and practical, and is the least expensive system to build. Block Diagram - adding a Storage Battery Figure 8 The only additional component needed is a Blocking Diode, a very inexpensive (less than $1) electronic device installed between the Solar Module or Array and the Storage Battery. The diode allows electricity to flow in only one direction (toward the battery), to prevent the battery from being slowly discharged by the solar cells during darkness. Most electronic supply stores stock blocking diodes. But, some of the best deals are through eBay You may have to buy the diodes in lots of 5-10 at eBay to get the best price, but if you're building a solar array you may need a diode for each module. I recommend the Schottky brand diode - it's recognized as an industry standard. For best reliability, be sure to select diodes rated for at least twice the current capacity of each module. This allows a generous safety margin (for example, a 4- amp module should use a diode rated for at least 8-amps). One of the most expensive, if not the most expensive, component of any solar electric system is the Storage Battery - and not just any old battery will do. You can't cut corners here, you must use a "deep- cycle" battery. Regular batteries such as those used in cars are "shallow-cycle." They're designed to provide lots of power for a short period of time, such as when the starter is cranking the engine. But, your Solar Wizard is an entirely different animal. It requires a "deep- cycle" battery that provides moderate power over the long-haul, and can be "deeply" and continually charged and discharged without damage or shortened life. They are used in many applications such as electric vehicles, wheelchairs, golf carts, forklifts, etc. One of the best sources I've found for "deep-cycle" batteries is: At Battery Company, Inc. They sell hundreds of different batteries, each designed for a particular application. If they don't have the battery you're looking for, nobody does. If you have access to the Internet, check out their website at: www.atbatt.com. In their website search windows choose "Electric Vehicle - Deep Cycle - 12V" - you'll be amazed at the selections. You can get a good education about batteries in general just from that site alone. You can also call or write for a copy of their catalog at: At Battery Company, Inc., 28918 Hancock Pkwy, Valencia, CA 91355 - - Sales & Customer Service; (877)528-2288 A typical solar system "deep-cycle" battery (100 to 200 amp-hour capacity) is very heavy, weighing about 75 to 150 pounds. So, shipping cost alone can be significant. You might consider buying locally from WalMart, Sam's Club, or Costco. It's unlikely that their employees will be able to offer you any meaningful advice, so be sure to choose a high-quality "deep-cycle" battery for your Solar Wizard. You can also search on eBay, you may just get lucky there. You may even be able to locate used "deep- cycle" batteries at bargain prices by doing some shopping around, but I don't recommend it. You never know what you're getting into with used batteries since they all look the same on the outside. The only way to determine the condition and capacity of a used battery is to run a performance test by placing the battery under load while tracking its discharge rate. Needless to say, this can get expensive. Even then you can't be 100% certain that the battery doesn't have internal damage that will show up later. My best advice is, avoid used batteries. Maintenance is a factor often overlooked when it comes to choosing the right batteries. All batteries contain an electrolyte, usually a mixture of water and sulphuric acid, or its equivalent. They also come in two varieties, "sealed" or "flooded." A flooded battery has caps that must be removed to periodically check the fluid (electrolyte) level since the water component of the fluid slowly, but continually, evaporates.. If fluid level is low, distilled water must be added to bring the fluid back to the recommended level. It may seem like a small point, but it's awfully easy to overlook this "minor" maintenance factor since solar systems will keep running for years at a time with little or no attention given to maintenance. If the fluid level of a flooded battery drops below the level of the battery plates, the battery may be permanently damaged, or destroyed. Safety is another factor to consider since flooded batteries give off hydrogen gas (which is explosive at concentrated levels) while charging. All battery installations should be vented and enclosed to prevent accumulation of hydrogen gas and accidental shorting. Sealed batteries contain chemically treated "mats" to absorb the hydrogen gas being produced while charging. Since they are sealed there is no electrolyte evaporation, thus no need for maintenance. Their downside is that they are more expensive than flooded batteries. Batteries are generally priced in line with their capacity - that is, according to their amp-hour ratings. A 200 amp-hour battery will usually cost about twice the price of a 100 amp-hour battery. There will be exceptions of course, so it usually pays to compare prices. If you're initially building a relatively small capacity Solar Wizard, 120- watts for example, I would recommend using a 100 to 200-amp hour storage battery. If you decide to increase system size later, you can always connect more batteries in parallel to boost storage capacity. Adding a Charge Controller A Charge Controller, as its name implies, controls the flow of charging current from the solar cells into the Storage Battery. If charging current is too high the storage battery will be overcharged, and may overheat, possibly causing the electrolyte to boil out. With a sealed storage battery, its case may even rupture since excessive hydrogen gas cannot be absorbed quickly enough by its internal chemical mat. At any rate, overcharging is a very bad thing and will quickly damage or destroy your storage battery. Charge controllers, as depicted in the Block Diagram of the following Figure 9, are required devices except for very low capacity solar systems. Block Diagram - adding a Charge Controller Figure 9 As a rule of thumb, a charge controller is needed in any system generating more than 5-watts of power for every 100 amp-hours of storage battery capacity. To determine if a charge controller is needed, simply divide storage battery capacity (amp-hours) by system power (watts). If the result is a number less than 20, a charge controller is needed. For example: If your Solar Wizard has a 100 amp-hour storage battery and generates 150-watts of power, dividing 100 by 150 yields the number .67 - so, a charge controller is required. As you can see, if your Solar Wizard generates 150-watts of power, you would need batteries with a total capacity of at least 3,000 amp-hours (150 x 20) to eliminate the need for a charge controller. That many batteries would fill a small room, not to mention being terribly expensive! In short, your Solar Wizard must be equipped with a Charge Controller. Most charge controllers contain circuitry, or internal blocking diodes, to prevent current being drained from the storage battery by the solar cells during the hours of darkness. Be sure to double-check your charge controller, and if such is the case there will be no need for connecting blocking diode(s) into wires exiting the solar cells. Solar charge controllers are rated according to storage battery voltage and the level of charging current (amps) they must control. Thus, the Solar Wizard requires a 12-VDC charge controller. In general, you should use a charge controller with current capacity of at least 1-½ times the current output from the solar cells. For example, if your Solar Wizard generates 8 amps, you should install a 12-VDC charge controller rated for at least 12-amps. I recommend at least doubling current capacity for the sake of added efficiency and reliability, so I would go with at least a 16-amp charge controller. Since charge controllers are relatively inexpensive, and you may want to eventually expand your system, you might consider a much larger charge controller, perhaps in the 50-amp to 75-amp range. Charge controllers are available with all kinds of optional features, at higher prices of course. Top-of-the- line charge controllers are equipped with special electronic circuits to sense the exact charge level of the storage battery. With a highly discharged battery, they automatically adjust output current to a high charge rate that continually tapers off as the battery gets closer to being fully charged. After the battery becomes fully charged, the controller shuts down altogether. This feature prolongs battery life since it's the ideal way in which to charge any battery. Other optional features incorporated into some charge controllers that you may wish to consider are: - A built-in battery charger that operates from household 115-VAC power for quickly charging a discharged battery. - Various meters to monitor system functions such as voltmeters, ammeters, and wattmeters. - Electronically altered charging to compensate for battery temperature changes, thus assuring ideal charge rates. - Terminal blocks to simplify interconnection of system wiring. There are many good sources available for purchasing high-quality charge controllers. I've found one that not only offers exceptional service and selections, but also has a very informative and educational website which you can visit at: store.solar-electric.com/ Here's pertinent information for contacting them directly, or requesting a catalog Northern Arizona Wind and Sun, 4091 E Huntington Dr Ste B,, Flagstaff, AZ 86004 Phone: (928)526-8017 - - Toll Free: (888)383-0195 Adding an Inverter Adding an Inverter to your Solar Wizard, as depicted in the Block Diagram of the following Figure 10, converts it into a totally functional and flexible home solar electric power system. Block Diagram - adding an Inverter Figure 10 An inverter changes 12-VDC power from the storage battery into 115-VAC power to run household appliances. As is the case with most electrical devices, inverters are designed and rated according to the power requirements demanded of them, and vary greatly in that respect. And, as you might expect, the greater their power handling capacity, the more costly they are likely to be. Very low power inverters that can handle but 100-watts or less are available at very low cost, but are much too small for practical use in solar electric systems. On the other hand, units capable of providing 10,000 watts or more are also out there - designed primarily for commercial use. Most home solar electric systems require inverters within the 2,000-watt to 6,000-watt range. Even if your Solar Wizard generates less than 200-watts, I recommend using an inverter rated for at least 2,000- watts. Inverters with high power capability tend to be robust in design, and are usually the most reliable. Large inverters also allow greater flexibility for future system expansion. Electricity distributed by commercial power companies is supplied as an alternating current in the form of a smoothly oscillating electrical wave termed a "sine" wave, and home appliances are designed to accept power in that form. For most appliances to accept power from inverters, the power must be supplied in the same form as commercially generated electricity, or in a nearly identical form. Two unique types of inverters are used with solar electric systems, and each provides an alternating wave form as either a "modified sine wave" or a "pure sine wave." The two types of inverters are: Modified Sine Wave Inverter - As its name implies, a modified sine wave inverter produces an alternating wave form somewhat modified as compared to the waveform of commercially generated electricity. High-quality modified sine wave inverters can be used to power practically all home appliances and devices. There are exceptions, of course, as will be explained later. However, the usefulness and efficiency of a modified sine wave inverter depends upon the degree to which its sine wave has been modified. Some low-cost inverters, because they are inexpensive to manufacture, generate wave forms that can more accurately be described as "square waves." Such inverters are generally useless, and can even damage some sensitive appliances, especially anything using an electric motor. Just be aware that some cheap modified sine wave inverters are on the market. Don't risk using them - deal only with reputable companies! Pure Sine Wave Inverter - A high-quality pure sine wave inverter produces a nearly perfect and "smooth" sine wave. In fact, most top-of-the-line pure sine wave inverters produce waves so "pure" that they are of even higher quality than the waves produced by most commercial power grids. Needless to say, such inverters can be used to power any home appliance or device. Their only downside is cost since they are relatively expensive. Which type inverter is best? I recommend using a high-quality modified sine wave inverter since most appliances and devices will work just fine with one. But some appliances, especially those with sensitive electronic controls, may tend to malfunction, or even refuse to work at all. Unfortunately, because we live in the "age of electronics," we're being presented with growing numbers of such appliances. All "highly-electronic" devices such as computers, printers, clocks, etc., tend to be very sensitive to the quality of their power sources. A good example is a television set, which may sound fine, but the screen image is wavy or distorted. The only solution for powering "problem" appliances and devices is to use a pure sine wave inverter. You might even consider using both types, a pure sine wave inverter to power your "problems" and a modified sine wave inverter to power everything else. Inverters are available with many extra features and options. As with charge controllers, expect to pay extra for any extras. Here are a few of the more interesting options: - Automatic "ON-OFF" to conserve power and extend inverter life by turning the inverter off when all appliances are turned off. - A built-in battery charger that operates from household 115-VAC power for quickly charging a discharged battery. - Various meters to monitor system functions such as voltmeters, ammeters, and wattmeters. - Terminal blocks to simplify interconnection of system wiring. If you have access to the Internet, an interesting website for learning more about inverters (and many other solar electric things) is: www.freesunpower.com. Here's an excellent source for inverters of every description: The Inverter Store, Inc., 9736 S Virginia St Ste A, Reno, NV 89521 Phone: (888)417-8673 Call or write them for a copy of their catalog. You can also check out their website at: www.theinverterstore.com Building Your Solar Wizard Building your Solar Wizard will be an enjoyable experience when you adhere to the following step-by-step procedures. Each step has been carefully thought out so as to eliminate the possibility of mistakes making your project fun, easy, and educational. Craftsmanship! Writing this publication has been a labor of love. But just when I thought I had finally put the "finishing touches" to it, I decided to go back and add this paragraph. Not because it's anything particularly astounding, but simply to emphasize the importance of CRAFTSMANSHIP. In short, your Solar Wizard will only be as good as you make it! Carefully built, it will give you many years of trouble-free service (it's not unusual for solar electric systems to still be cranking away after loyally operating for 30+ years). So, please pay attention to even the "small" details - they are the things that will make your Solar Wizard reliably "crank away" for years to come. JUST DO YOUR BEST TO MAKE YOUR SOLAR WIZARD SOMETHING TO BE PROUD OF! Testing Solar Cells Note: Solar cells are fragile things No matter how carefully you handle them, mistakes are likely to happen and you may damage or destroy a few along the way. Some may have even been damaged in shipment. It always pays to buy extra cells in advance just to cover yourself. Even if you end up with a few extra cells, you can always use them later if you decide to upgrade your Solar Wizard by adding additional modules (thus creating an array). Solar cells, like most electronic components, are extremely reliable. But nothing's perfect, and now and then some folks will end up with a bad cell or two. With that in mind, it's of utmost importance that you inspect and test each and every solar cell before installing it in your Solar Wizard module - it's an easy thing to do. After completion, each module is more or less a "sealed unit." It's a real pain to have to open a sealed module just to replace a defective cell simply because you didn't take a minute or so to inspect and test it beforehand (I speak from experience here!). First off, do a visual inspection of each cell for minor damage such as scratches or small chips along the edges. The key word here is "minor." Obviously, major defects are grounds for rejection. But small edge chips or a scratch here and there are no big deal - such cells should still work just fine. You can even buy kits to "repair" minor scratches from places like eBay, and solar supply stores. Your final check must be to confirm that each cell is generating the correct voltage by testing it with a voltmeter. There's no need to spend a lot of money here - for about $10 you can buy an inexpensive voltmeter at any Radio Shack or electronics store (or just borrow one from a friend). Obviously there has to be at least some sunlight to allow a solar cell to generate electricity. But even on cloudy days, or when the sun isn't shining very brightly, there will probably be enough sunlight to conduct accurate voltage tests. All solar cells have metal connection strips on both top and bottom surfaces. On so-called "tabbed cells" metal tabs will also be protruding from the top surface (the surface facing the sun). The top surface strips will be negative (-) polarity, and the bottom surface strips will be positive (+) polarity. Be sure to observe the correct polarity with your voltmeter when testing cell voltage. Each cell should measure at least 0.4- VDC. Reject any cell testing under 0.4-VDC. If the sky is so cloudy that you can't get reliable voltage readings (not likely), or if it's nighttime, you can always test indoors under a strong artificial light. If you have a solar powered calculator, and the light is strong enough to allow it to operate, the light should be strong enough to do accurate voltage checks on individual solar cells. Module Layout The exact layout of the individual solar cells within your Solar Wizard module is not at all critical, it's simply a matter of personal preference. A typical layout of a 6 x 6 cell module is shown on the following Figure 11. Any other module layout, such as 4 x 9, will work just as well. Typical Module Layout Figure 11 To conserve material, and to keep the size and weight of your Solar Wizard module within reason, you should arrange the cells with minimum spacing dimensions, allowing about 1/4-inch clearance between cells and along the edges of the module frame. Because solar cells come in all shapes and sizes, you can go nuts trying to work out the correct dimensions of the module housing mathematically. The quickest and easiest way I've found to design a nice cell layout is to simply trace the outline of a single cell onto a sheet of paper and then make 35 exact copies of the same tracing. It may seem like a lot of trouble, but the end result will be well worth the effort. Otherwise, even a small mistake in math may cause you to have to build the entire module housing all over again. Procure a large sheet of kraft paper (cheap and coarse paper, usually on rolls, used for making grocery bags, etc.) or simply glue or tape large sheets of scrap paper together. Using scissors, cut out the cell tracings and carefully tape or glue them to the paper in horizontally aligned rows and vertically aligned columns with about 1/4-inch spacing between adjacent tracings. Provide a space of about 1/2-inch between the two middle rows of cell tracings and also around their outer borders to allow room for wire routing and for wood screws to hold the mounting panel in place, as shown in Figure 11. Module Housing Using the cell layout suggested in Figure 11 as a pattern for the module housing, construct the housing with 3/4-inch to 1-inch thick plywood sheet and 3/4-inch square wood strips, as depicted in the following Figure 12. Be sure the dimensions of the housing "well" match the outer edge dimensions of the cell layout pattern. Note: For best durability and weather resistance, I recommend using marine-grade plywood since it's laminated with waterproof glue. Module Housing Figure 12 Secure the wood strips to the plywood sheet with #6 drywall screws (either 1-3/8" or 1-5/8") installed through the plywood and into the strips, as shown in the following Figure 13 - being sure to space the screws at about 6-inch intervals. Module Housing Construction Lower Side View Figure 13 For added strength and durability, and to help seal the housing seams, also use a waterproof glue such as "Resorcinol Waterproof Glue" on all mating surfaces. Resorcinol is made by "DAP Weldwood" and is available at most large hardware stores. Using a 3/8-inch drill bit, drill five equally-spaced vent holes into the lower side of the module housing as shown in Figure 13. Note: The lower side of the module will be facing downward to prevent moisture (dew and rain) from entering the module through the vent holes. Determine the correct cable size required to connect your Solar Wizard module to a 12-VDC charge controller by referring to the Cable Size chart, shown in the following Figure 14 Cable Size Chart Figure 14 Note: Insulated cable (often referred to as large gauge stranded wire) can be purchased at electrical supply stores. Be sure to purchase high quality low-voltage cable made for outdoor exposure (UV protected insulation). Correct cable size is dictated by both its required current capacity and its length. If the cable is either too small in size or too long, it will have high electrical resistance, which will cause excessive power loss and overheating. The Cable Size chart is based on a cable power loss of 2% (0% loss is impossible). To determine correct cable size, make note of the current that will be generated by your Solar Wizard. A typical system might generate 8-amps, as with the example presented in the “Solar Cell Power” section. Estimate the distance from your Solar Wizard to the charge controller - for example, 35-feet. Since two cables are needed, total cable length will be 70-feet. Referring to the left column of the chart, locate the 8-amps row and then follow across that row to the next highest length, which is 86-feet in this example. Follow that column straight up to the "Cable Size (Gauge)" row and you'll find that you should use #2-gauge cables. Even though low-voltage electrical cable is relatively expensive, I recommend using the next larger size (#1-gauge in this example). That way you can cut power loss to about 1%, gaining an additional 1% capacity (which will eventually save enough power to more than pay for the extra cable cost). After purchasing the appropriate cable, measure its diameter and drill two more slightly oversize holes (one for each cable) into the lower left side of the module housing as shown in Fgure 13. Be sure to keep the two cable holes as close as possible to the left edge of the housing to prevent shading of the cells by the cables. Using a high-quality exterior paint primer for wood, apply an even coat of primer to all surfaces of the module housing, both inside and out (including the insides of the vent and cable holes). After the recommended drying time for the primer, apply 3 or 4 heavy coats of high-quality exterior (UV resistant) house paint to the same surfaces of the module housing. Cell Mounting Panel Note: Building a Cell Mounting Panel is optional since the cells can be directly mounted to the module housing "floor." But I highly recommend using a separate panel since the entire cell Assembly can be easily removed for repair or component replacement if a failure occurs (such as a broken solder joint, disconnected wire, damaged or cracked cell, etc.). Also, the panel positions the cells closer to the module cover where they will be less affected by possible shading from the sides of the module. Just about any sturdy non-metallic and non-conductive material will be fine for the mounting panel. Some good choices are pegboard, particle board, or plain old plywood (no need for marine plywood since the panel is enclosed). Fabricate a Cell Mounting Panel from sturdy material about 1/8" to 1/4" thick with the same dimensions as the inside of the module housing "well." If necessary, trim the edges of the panel to obtain a slightly "loose" fit in the well to prevent jamming during panel installation or removal. As was done with the module housing, apply exterior wood primer and at least three heavy coats of exterior paint to all surfaces of the panel to prevent warping due to humidity changes. Note: While waiting for the module housing and cell mounting panel paint to dry for the recommended time, let's move on to the next phase, connecting the individual solar cells to create your Solar Wizard module. Connecting the Module Cells Note: Solar Cells are configured with conductive metal strips on both their top and bottom surfaces. The top strips (those facing outward toward the sun) are of negative (-) electrical polarity, while the bottom strips are of positive (+) polarity. The cells shown below are referred to as "tabbed" cells since they have conductive strips protruding outward from the top surfaces. If your cells are not tabbed, you will have to use "tabbing ribbon" to interconnect them. Tabbed Cells Figure 15 The top tabs of each cell are soldered to the metal strips on the bottom of the next cell in the string as shown below. Thus, electrically connecting them in series so that the voltage of each added cell is cumulative. Tabbed Cells Connected in Series - Top View Figure 16 Tabbed Cells Connected in Series - Side View Figure 17 Note: Before connecting the module cells, be sure that all cells have been tested and verified to be generating a minimum voltage of 0.4-VDC as described in the "Testing Solar Cells" section. CAUTION: SOLAR CELLS ARE EASILY DAMAGED AND MUST BE HANDLED CAREFULLY. EXCESSIVE HEAT BUILDUP WILL DAMAGE OR DESTROY SOLAR CELLS. USE A LOW WATTAGE "PENCIL" STYLE SOLDERING IRON AND AVOID UNDUE PRESSURE ON CELL CONTACTS WHILE SOLDERING. USE ROSIN-CORE SOLDER ONLY, ACID-CORE SOLDER WILL DAMAGE SOLAR CELLS. WARNING: SOLDER FUMES ARE TOXIC AND CAN BE HAZARDOUS TO HEALTH. PROVIDE ADEQUATE VENTILATION WHILE SOLDERING TO PREVENT INHALATION OF FUMES, AND WEAR EYE PROTECTON. CONSIDER USING A FUME EXTRACTING DEVICE. 1. Using a small soldering iron (25 to 35 watts) with a chisel style tip, connect the necessary number of solar cells in series to create a single string of cells the approximate width of the cell mounting panel as shown in the following Figure 18. Be sure to keep the cells accurately aligned, with gaps of about 1/4-inch between cells. 6-Cell Series Connected String Figure 18 Note: Refer to the preceding Figures 15 - 17 before starting this procedure. To avoid excessive heat buildup, solder only one contact of each cell and wait until the cell cools before soldering the other contact. Before soldering, use a flux pen to clean the cell contacts and tabs. To assure best results, use only solder intended for electronic work, such as 60/40 rosin-core solder. If your cells are not tabbed, you can use wire, such as #18-gauge stranded wire (stripped of insulation), to interconnect the cells. Tabbing wire (ribbon) and buss wire (ribbon) can also be used, and can be purchased from many Internet sources, including eBay. Here are three Internet sources, which I recommend, that carry a large inventory of solar electrical system supplies: greenhouseroofing.com solar-deals.com stores.ebay.com/HEARTOFTHESUN-SOLAR 2. Solder the remaining cells into separate series-connected strings (for a total of 36 cells) by repeating the procedure of Step 1. WARNING: CARBON TETRACHLORIDE IS A TOXIC AND HAZARDOUS SOLVENT. BE SURE TO OBSERVE ALL SAFETY AND HANDLING PRECAUTIONS IN ITS USE AND USE ONLY IN A WELL VENTILATED AREA. 3. To assure good adhesive bonding, the bottom surfaces of the solar cells must be as clean as possible. I recommend carefully cleaning their bottom surfaces with a soft clean cloth dampened with carbon tetrachloride (carbon tet). Be sure to wear protective rubber gloves since carbon tet can be absorbed directly into the bloodstream through the skin. 4. Using a soft clean cloth dampened with carbon tet, carefully clean the bottom surfaces of all the solar cells. Note: Silicone caulk is very versatile, and is an excellent adhesive, sealant, and caulk. It is a RTV (Room Temperature Vulcanizing) substance containing acetic acid. The acid chemically reacts with moisture (water) in the air to cure the caulk. Low temperature and dry air (low humidity) slows its curing time. Note: For ease of handling and to prevent cell damage, I recommend placing each string of cells on a strip of thin wood or heavy cardboard with the bottom surfaces facing upward. After caulk is applied, the cells can be positioned above the mounting panel and carefully flipped over and onto the panel. WARNING: SILICONE CAULK CONTAINS ACETIC ACID WHICH IS A SKIN AND EYE IRRITANT. BE SURE TO OBSERVE ALL SAFETY AND HANDLING PRECAUTIONS IN ITS USE, AND USE ONLY IN A WELL VENTILATED AREA. CAUTION: SILICONE CAULK IS APPLIED TO THE BOTTOM CENTER OF EACH SOLAR CELL TO ATTACH IT TO THE MOUNTING PANEL. DO NOT APPLY CAULK TO THE ENTIRE BOTTOM SURFACES OF THE CELLS - ONLY A DAB IS NEEDED. YOUR SOLAR WIZARD WILL BE EXPOSED TO WIDE TEMPERATURE SWINGS FROM DAY TO DAY - HEATING AND COOLING WILL CAUSE THE PANEL AND CELLS TO EXPAND AND CONTRACT AT SLIGHTLY DIFFERENT RATES. IF TOO MUCH CAULK IS APPLIED, THE CELLS MAY EVENTUALLY LOOSEN OR BE DAMAGED. 5. Place the cell mounting panel onto a flat and level surface in a room temperature work area. If necessary, adjust the first string of cells so that they will lay flat against the surface of the panel after being attached. Position the cells onto a strip of wood or heavy cardboard with their bottom surfaces facing upward. 6. Place a large dab (about 1/2-inch in diameter) of silicone caulk in the middle of the bottom surface of each cell in the string and carefully flip the cells over and onto the panel. Locate and adjust the position of the string of cells near the bottom of the panel as shown in the following Figure 19. Cell String Positioning on Panel Figure 19 7. Using very light pressure, carefully press against the top center of each cell to assure that the silicone caulk adheres to the panel. 8. Attach the remaining cell strings to the mounting panel (as shown in the following Figure 20) by repeating the procedure of Steps 5 through 7. Cell Strings Positioning on Panel Figure 20 Note: Do not disturb or move the cell mounting panel for at least 4 or 5 hours to allow adequate time for the silicone caulk to partially cure. CAUTION: SILICONE CAULK CURES VERY SLOWLY AND EMITS ACETIC ACID FUMES WHILE CURING. TO PREVENT "FOGGING" OF THE TRANSPARENT MODULE HOUSING COVER BY ACID FUMES, DO NOT INSTALL THE MOUNTING PANEL INTO THE HOUSING UNTIL THE CAULK HAS FULLY CURED. Note: If humidity is low in your workshop area, you can speed caulk curing by surrounding the cell panel with water dampened rags or towels. Drape a lightweight plastic sheet over the panel and rags/towels to trap moisture. Re-wet the rags/towels as the water evaporates. 9. You must allow the silicone caulk to cure for at least 4 to 5 days before installing the mounting panel into the module housing. While waiting for the caulk to fully cure, continue on with the following procedures. Note: To assure that the interior of the sealed module is as clean as possible after final assembly, the following Steps 10 through 14 are temporary procedures. After each step is completed, the part will be removed and then reinstalled after the cell mounting panel has been installed. 10. Thread the two Power Cables through their assigned holes in the module housing as shown n the following Figure 21. Locate each of two Insulated Cable Clamps approximately 2-inches from the upper and lower sides of the housing well. Temporarily secure each cable to the side of the housing well with a clamp and wood screws. Remove the screws, clamps, and cables. Note: Insulated Cable Clamps can be purchased at any electrical supply store. Power Cable Routing Figure 21 11. Record the outside dimensions of the module housing. To make the Housing Cover, purchase 1/4-inch thick clear "Plexiglas" acrylic sheet or clear "Lexan" polycarbonate sheet cut to the dimensions of the housing as shown in the following Figure 22. Add an extra 2-inch "lip" to the lower edge of the sheet to help prevent rain from entering the housing vent holes. Housing Cover Figure 22 Note: Plexiglas and Lexan sheet can be purchased from large plastic supply stores - they should be able to custom-cut it to size. If there is not a nearby store in your area, I highly recommend purchasing from: United States Plastic Corp., 1390 Neubrecht Rd., Lima, OH 45801-3196 Phones: Customer Service: (800)769-1157 - - Technical Service: (800)821-0349 - - Toll Free Ordering: (800)537-9724 They have provided me with friendly and excellent service for many, many years. You can request a copy of their catalog, and visit or order from their website at: usplastic.com CAUTION: PLEXIGLAS CRACKS AND CHIPS VERY EASILY WHILE BEING DRILLED. USE A SPECIAL DRILL BIT ESIGNED FOR DRILLING PLEXIGLAS, OR MODIFY A STANDARD METAL DRILLING BIT BY DULLING ITS CUTTING EDGES WITH A TOOL SHARPENING STONE (WHETSTONE). HOLD THE PLEXIGLAS FIRMLY AGAINST THE DRILLING SURFACE AND USE LIGHT PRESSURE WHILE DRILLING. LEXAN IS MUCH LESS APT TO PRESENT DRILLING PROBLEMS. TO PREVENT SCRATCHING PLEXIGLAS OR LEXAN, DO NOT REMOVE ITS PROTECTIVE PAPER COVERING UNTIL INSTRUCTED TO DO SO. 12. Referring to the preceding Figure 22, mark the locations on the cover’s protective paper for the Wood Screw holes to be drilled for attaching the module cover to the housing. Locate the drill holes at about 4" to 6" intervals. Obtain a 3/16" bit designed for drilling Plexiglas, or modify a 3/16" metal drill bit by slightly dulling its cutting edges with a tool sharpening stone (whetstone). Perform test drilling on scrap pieces of Plexiglas to be sure the bit has been properly modified. If necessary, rework the bit cutting edge to obtain the desired results. Using light pressure, carefully drill 3/16" holes at all the marked locations on the module cover. 13. Obtain the required quantity of #8 x 1" round head Wood Screws for attaching the module cover to the housing. Carefully position the module cover onto the housing and temporarily attach it with wood screws. Note: For durability and appearance, I recommend using stainless steel wood screws. 14. Remove the wood screws and cover from the housing and go on to Step 15. 15. Referring to the following Figure 23, trim or bend the cell tabs and/or wires so as to allow at least 1/8" clearance from the sides of the module housing after the mounting panel is installed. Module Wiring Figure 23 CAUTION: AS SOON AS THE SOLAR CELLS ARE EXPOSED TO SUNLIGHT EACH CELL STRING WILL GENERATE A SIGNIFICANT LEVEL OF ELECTRICAL POWER. TO PREVENT POSSIBLE DAMAGE DUE TO ELECTRICAL SHORTING WHILE SOLDERING THE STRINGS, I RECOMMEND SHIELDING THE CELLS BY WRAPPING AND TAPING A LAYER OF THIN BLACK PLASTIC FILM AROUND ALL BUT THE ENDS OF THE CELL STRINGS. Connect the strings of solar cells by soldering their tabs and/or wires in series as shown in Figure 23. Note: Figure 23 is only intended to clarify electrical interconnection of the cell tabs and/or wiring. It shows the correct electrical connections and wiring sequence for connecting the cell strings in series. The actual wiring must be arranged to provide at least 1/8" clearance with the sides of the module housing after the mounting panel is installed.