DIY Solar Panel FAQ

1.     Solar Cells BaSICS (Polarity, efficiency, life span, MATERIALS, how it works, how string ribbon is made, etc.)

Q1.1. How many watts would I get with a 36 cell panel?

Q1.2:  How many cells would I need to produce a gigawatt ?

Q1.3. How solar panels are professionally made?

Q1.4: Please help me understand why solar cells are in different sizes.

Q1.5: Do you have instruction manual on how to make cells into string? 

Q1.6: I want to build 24 V panels. If I make the 175W panel by using the 100 cells, how do I determine what to do to make them 24 Volt?

Q1.7: What are the differences between DIY and professionally made panel? I want to charge 12v deep cycle batteries. But if I want to link several batteries and want more than 40 watt output would I take several 12 volt panels and link them separately into the battery input?

Q1.8:  What is the weight of 1 3x6 solar?

Q1.9: Do these solar cells need a direct sun light or it is enough with day light? How would sun light change the output level?

Q1.10: Are these cells semiconductors?

Q1.11: Do these solar cells need a direct sun light or it is enough with day light? How would sun light change the output level?

Q1.12: Is 'multi-crystalline' cell the same as "poly-crystalline' cell? Why some polycrystalline are cells so expensive ($3 per watt) and your cells can be as low as $1.50 per watt?

Q1.13: What's the total wattage for these 100 cells you sell?

Q1.14: Do static build up and heat buildup (in direct sunlight) become a problem with the solar panels? Would you need a specialized frame be needed to prevent sparking and be fire proof?

Q1.15: I saw the photos of the low-priced cells which have little cuts (Grade B cells), are all the cells in this category have the same defects? Is the efficiency of these cells lower?

Q1.16: What percentage efficient are these solar cells? Do the chips decrease the efficiency? If so how much "estimated"? Could you provide directions on how to solder wires/leads to these cells?

Q1.17: What is the difference between Evergreen Solar Cells to make DIY solar panels and solar cells with small chips?

Q1.18: Which side of the cell is positive, and which side is negative?. The blue shine face is positive or negative? I check with two Multimeters and it tells me that the blue side is negative. Is this correct?

Q1.19:  I was wondering what other components I need to buy in order to assemble a complete solar panel. Do you sell these other items? What else do I need to make a complete off-grid power generation system?

Q21.0: What kind of uses can these cells do for me? For example, could a laptop run off these so that I do not get charged from the electric company? Same with a LCD TV, etc.

Q1.21. How many types of solar cells are out there? Which one is comparatively better and why?

Q1.22: Whatís the difference between series and parallel?

Q1.23: I purchased 100 cells from you a month or so ago and really need the tabbing wires, flux, and solder to assemble them. Can I purchase these accessories separately and for how much?

Q1.24: I was looking for some tabbing wire and the description had this in it:

"For the Evergreen cells that are now so prevalent the problem isnít the wire used, it is the cells themselves. They simply should not be for sale for DIY use due to their fragility. They are the thinnest cells on the market besides some Belgian multi contacts and are for MACHINE ASSEMBLY. If you hear a crunch when soldering, that is a micro crack forming and has rendered the entire string of cells basically useless as it will create a pooling point for the electricity and will heat up a panel at those junctions, eventually becoming a fire hazard. It may take year or two for it to surface but the panel will eventually fail and be underpowered-long after most of these people will be in business."

Is this true?

Q1.25: I see your tabs are rated at .5 volt@3.5amp. Do you supply 12v. cells and at what amp? Would this rating be easier to work with 12v storage batteries than the lower rating?

Q1.26: Are these grade A solar cells? You show 36 cells = 18 volt = a 12 volt panel. All of my 12 volt panels are 22 Volt open circuit. Would 36 of these cells give me 22 volt open circuit to match them or would I need more cells per panel?

Q1.27: What is the difference between the USA and Germany cells? Which one should i purchase and does pretabbed mean that the wires are already connected where the other ones i would have to connect myself?

 

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Q1.1. How many watts would I get with a 36 cell panel?

A: The factory standard wattage per cell is 1.75 watts. So 36 cells panel will theoretically gives you 63 watts. But then cell production quality varies and some cells can have lower power than the standard rated cells. According to Evergreen Solar, 2% of the unsorted cells can have low power, and if you connect all the cells in series, the panel wattage power will be a multiplier of the lowest power cells. Just like the water flow is determined by the narrowest pipe in the whole plumbing system. Before connecting all the cells together on your panel, you need to test each cell and take out those very low power cells. The cells that we are currently selling are mostly with good, known power, so we are fairly confident with our solar cells. However, we never give any guarantees on that EACH and EVERY cell will perform to the specifications. So, we give some bonus cells to compensate for the lack of guarantee from us, and so far our customers have been very happy with the deals they have got.

The other reason for your panel to not have the total possible wattage power is your panel production techniques. Your soldering of tabbing wires on the cell bus bars may not be optimal; the glass you buy may only take in a certain percentage of the sun, etc... The reasons are many, but the joy here is to learn about Solar and still generate power at much cheaper rate than the professionally made panels.  

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Q1.2. How many cells would I need to produce a gigawatt ?

A:   1 megawatt = 1,000,000 watts, 1 gigawatt = 1,000,000,000 watts, 1 Evergreen cell ~ 1.75 watts ball park, so you need at least 571,428,571 cells. The No. 1 solar manufacturer in the world doesn't even make 1 gigawatt a year, today.

  

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Q1.3:  How solar panels are professional made?
 

A.  Let us explain to you how solar panels are professionally made.

1) The most important part in a solar panel is the solar cell. Each individual cell is a functioning power generating device, and they are fragile. Our cell comes with factory standard, which has 0.5 volt (voltage) and 1.75 watts (wattage), or 3.5 amps (current) in theory. You need to connect them in series to increase voltage or connect them in parallel to increase current. Then you use tabbing wires to do connect cells together. Tabbing wires are thin and flat, roughly 1 to 2 mm wide, which is probably what you meant by silver tape. They could be silver coated copper wires. The wider thin wires (called bus wires, roughly 3 to 4 mm wide)  are use to connect two or more series together. So you need tabbing wires, bus wires, solder, and rosin flux to make soldering easy and clean.

2) After the solar cells are connected and tested to generate the desired power output, then you need to protect them. Since cells are fragile, you need to protect them by laminating them between (first) two layers of EVA, (second) then TPT at the bottom (back side of the finished solar panel), (third) solar glass on top of the connected solar cells.

3) Then, you enclose these combined 5 layers in an aluminum frame, which is what you call chassis.

4) Lastly, you put on a junction box that connects to the positive and negative wires from the solar cells. The junction box is put at the back of the solar panel, along with the final connecting wires that enable you to connect to other devices of the solar power system, such as charge controllers or other finished panels.

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Q1.4. Please help me understand why solar cells are in different sizes.

A: Evergreen Solar only makes solar cells that are 3x6 inches in size (to be exact 80 mm x 150 mm). That's the factory standard and they don't use other sizes on their panels.

The reason you see different sizes is that other resellers re-cut them into sizes that are smaller than 3x6. They cut them into smaller sizes for two reasons: A) the standard size cells have a broken corner on the side or has a crack length wise, but even broken cells can still generate power, so for aesthetic reasons you want to cut them into smaller uniform sizes to make them look nicer. B) Sometimes, you need smaller sizes because you want to make a panel that generates only 10 watts for your smaller battery, but then you need the voltage to be higher, say 18 volts. To increase the voltage you connect 36 solar cells in series (each cell is around 0.5 volt), but then if you use the original size 3x6 solar cell the wattage will be too high (each cell is roughly 1.5-1.75 watts). So in this case, you need to cut the cells into smaller size to get the voltage you need, but smaller cells give you less current, yet maintains at 0.5 volt. So if you cut a standard 3x6 cell (0.5 volt, 1.75 or 1.8 watts for easy calculation) into 6 uniform 1x3 solar cells, you can make a lot of combinations by mixing connection in series or parallel.

The cells sold on eBay are usually cut with home made tools. During cutting, smaller broken chips on the edges of the smaller solar cells happen quite a bit, so the best tool to use is using YAG laser cutter. But laser cutters are expensive, so only the companies with long term commitment and resources can do it. This is not a problem for us, Everbright Solar. We do have laser cutters, and we can help you cut into solar cells different sizes based on your request. 

The sizes of other standard cells are 125 mm x 125 mm or 156 mm x 156 mm. Solar cells' base materials are silicon wafers. They are in these sizes because manufacturers made the wafers in these sizes. Most of the current solar manufacturing equipments are configured or made to produce wafers at these sizes.

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Q1.5: Do you have instruction manual on how to make cells into string? 

A: All items we sell on eBay do not come with instructions as we sell them at a very cheap price. However, we can include the manual upon your request, please make sure you put your request WITHIN your order in "Buyer's Message", so we won't overlook it; otherwise our shipping dept. will just ship it out as any regular order

You can google or watch free videos at www.youtube.com by searching 'how to make a solar panel' for further information.

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Q1.6: I want to build 24 V panels. If I make the 175W panel by using the 100 cells, how do I determine what to do to make them 24 Volt?

A: It's important to understand the concepts of series connection and parallel connection. Series connection increases voltage but not amperage; parallel connection increases amperage but not voltage. Series connection is when you connect the positive terminal of a cell with the negative terminal of the next cell. Parallel connection is when you connect the positive terminals of all cells in the set of cells with a tabbing wire and all the negative terminals of all cells in the same set.

So, in your case, since each cell is 0.5 volt so to make 24 volts you connect 48 cells in series (positive electrode of one cell to the negative electrode of the next cell, daisy chaining), and then you repeat the process to make another independent set of 48 cells series. Now you have two sets of 48 cell series. Next, you do the parallel connections, meaning - connect the positive to positive of the two 48 cell series using bus wires (thicker wires than tabbing wires that connect individual cells) and negative to negative of the two series. The reason you want to do parallel connection between the two sets of 48 cells is because you don't want the voltage to be too high. That will use up about 96 cells, a good thing, because you will break some and it's good to have some extra left around, and do practice first. We normally provide Buyer with some bonus cells so that you can screen out the low power cells. Another thing to remember is that no matter what kind of connections you have, the wattage will always multiply according to the number cells your have, but the total wattage of the whole panel will equal to the multiplication of the lowest rated cell in your series. So that's why you want to check each cell and take out the low power cells. That's the other reason we provide additional cells.

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Q1.7: What are the differences between DIY and professionally made panels? I want to charge 12v deep cycle batteries. But if I want to link several batteries and want more than 40 watt output would I take several 12 volt panels and link them separately into the battery input?  

A: You can watch free videos by going to YouTube.com and search for 'how to make a solar panel'. We can also include a copy of instruction manual WITHIN your order based on your REQUEST. You need to put this request in "Buyerls Message", so we won't overlook it; otherwise, our shipping department will just ship it as any regular order.

Whether if you should buy a ready made panel or not, please consider the following:

DIY pros: Solar education, solar career development, lower cost
DIY cons: Long process, could be frustrating, need to get materials from different sources, quality not as high as ready made panels.
 
Preassembled Pros: Higher quality, power output guaranteed, not as many hassles, saves time
Preassembled cons: Higher cost, loss of learning opportunity in panel making  

When charging your batteries, find out the battery specs, the voltage, the amps, the time it takes to charge it etc. To make panels, itís important to understand the concepts of series connection and parallel connection. Series connection of the cells increases voltage but not amperage; parallel connection of the cells increases amperage but not voltage. Series connection is when you connect the positive terminal of a cell with the negative terminal of a next cell. Parallel connection is when you connect the positive terminals of all cells in the set of cells with a tabbing wire and all the negative terminals of all cells in the same set.
 
So, in your case, since each cell is 0.5 volt so to make 12 volts you connect 24 cells in series, and that gives you 24*1.75 watt= 42 watts. If you need more wattage then you repeat the process to make another independent set of 24 cells series. Now you have two sets of 48 cell series. Next, you do the parallel connections. The reason you want to do parallel connection between the two sets of 24 cells is because you don't want the voltage to be too high. 48 cells give you 84 watts, but since its parallel connection, you still get 12 volts.

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Q1.8: What is the weight of 1 3x6 solar?

A: Each 3x6 solar cells weigh about 6 grams, without tabs. Depending on the voltage and amps that the motor for your plane requires, you might need to connect the cells in a combination of series or parallel connections together. Each cell is only about 0.5 volt, so you will want to try different layout of your cells so that your panel generate enough power to the motor for the plane.

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Q1.9:  Do these solar cells need a direct sun light or it is enough with day light? How would sun light change the output level?

A: The solar panels made from these solar cells will perform best under direct sun light. It will also work even under cloudy conditions, but they obviously won't generate as much output. There are science experiments on how much lower power it under darker or cloudy conditions, but we don't have the specifics. 

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Q1.10: Are these cells semiconductors?

A: These cells are made out of semiconductor materials - hyper pure silicon. Silicon is one type of semiconductor, because it can conduct electrical current or not conduct current depending on what kind of materials and how much of those you add to the silicon. Because of this property, silicon is used a lot in integrated circuit chips, and it is also the most widely used materials in making solar cells. Over 90 percent of all solar cells on the market today have pure silicon as their base materials. And this high percentage will remain high for a number of years to come.

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Q1.11: Do these solar cells need a direct sun light or it is enough with day light? How would sun light change the output level?

A: The solar panels made from these solar cells will perform best under direct sun light, but it will also work even under cloudy conditions, but they obviously won't generate as much output. There are science experiments on how much lower power it under darker or cloudy conditions, but we don't have the specifics. 

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Q1.12: Is 'multi-crystalline' cell the same as "poly-crystalline' cell? Why some polycrystalline are cells so expensive ($3 per watt) and your cells can be as low as $1.50 per watt?

A: Multi-crystalline and poly-crystalline refers to the same thing, which is the base wafer type on which the solar cell is made. Monocrystalline's based wafers (cells) are made from a single crystal that's round like a big cylinder and the cells are typically higher in efficiency.

Put that aside, some Buyers want a cell size that's different from our cell, which is 3x6 and puts out a lot of power per cell. Some other buyers want cells that are smaller in size, but then they also output lower power. So you need to string more smaller cells to get the equivalent amount of power of bigger cells. If you string our cells (which is the factory standard) and also string the same number of smaller cells to get the same amount of power, the smaller cells panel will generate much higher voltage and it can fry the battery that you want to charge. You just can not compare on a per watt basis, although we know that we have the value under the Sun. We are setting up an expensive YAG laser cutter in our new facility that will cut tens of thousands of cells for our customers. YAG laser is the right way to do it - all solar panel manufacturers use that. So bottom line is they are a little more expensive because they are rare, but also because the total dollar amount that people spend per deal on them is also smaller and more affordable. Our buyers routinely spend hundreds of dollars per deal on our products without blinking their eyes, and they keep giving us 100% positive feedback and 5 stars.

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Q1.13: What's the total wattage for these 100 cells you sell?

A: Theoretically, 100 cells times 1.75 is 175 watts, but we can not guarantee wattage for each cells or the total wattage. If we guarantee wattage then it will be about at least $2.00 per watt. The factory standard wattage per cell is 1.75 watts. But then cell production quality varies and some cells can have lower power than the standard rated cells. According to Evergreen Solar, 2% of the unsorted cells can have low power, and if you connect all the cells in series, the panel wattage power will be a multiplier of the lowest power cells. Just like the water flow is determined by the narrowest pipe in your whole plumbing system. Before connecting all the cells together on your panel, you need to test each cell and take out the very low power cells. We give our customers few more cells than what they paid for, and we think that more than compensates the potential loss of wattage power.

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Q1.14: Do static build up and heat buildup (in direct sunlight) become a problem with the solar panels? Would you need a specialized frame be needed to prevent sparking and be fire proof?

A: I am not an expert in static and heat build up, but as far as I know static and heat build up has not been a fire problem with the solar panels. However heat is build up is not good for solar cell efficiency and energy harvest. Solar panels perform better in cooler regions in terms of the percentage of sunlight hitting the panels that gets converted into electricity.

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Q1.15: I saw the photos of the low-priced cells which have little cuts (Grade B cells), are all the cells in this category have the same defects? Is the efficiency of these cells lower?

A: This is what we consider the grade B cells. We sort all of our cells individually and group them using consistent criteria. Grade B cells all have tiny defects that are a little noticeable to trained eyes, but look closely at the edge of the solar cells (in close up picture) - along the edge of the cells there is a tiny line that travels along the contour of the chipped corner. This indicates that this chip happened during the production process, before the solar cell edge was sealed. (Most people don't know that Evergreen has a step to seal the edges of the solar cell production step). This also means that this chip did not occur because of rough handling or under other duress post production.

Since you are losing some area coverage, theoretically, or by science, there has to be some power loss, but then when you look at the total area of coverage that got loss, the power loss should be minimal, and also because almost all of the finger lines (those 31 thin lines on the front of the cells for energy harvest) are essentially intact. You can consider these tiny finger lines to be little creeks feeding water to the main rivers - the two thick white bus bars.

We sell all of our cells exactly as described, and we are so confident of these cells that we are going to relax the return policy so that you can return these cells if you don't like them with no questions asked. The truth is, product returns have not been a problem for us. People recognize good deals when they see one, especially after they compare ours with others out there. For product returns, most of our other competitors will only refund the cost of products, NOT shipping to you. You pay for return shipping. But really this shipping discussion is moot because we are confident you will find them acceptable. Purchase with ease of mind...

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Q1.16: What percentage efficient are these solar cells? Do the chips decrease the efficiency? If so how much "estimated"? Could you provide directions on how to solder wires/leads to these cells?

A: Efficiencies are anywhere from 1% to 14% or so, which almost says that we don't guarantee efficiency, and we rectify that by giving a generous percentage of extra bonus cells for free to compensate for that lack of guarantee. We have shipped tens of thousands of cells in the past 30 days to enormous number of customers, and they have all been very happy with the deals they got. I don't think we can say more convincingly than those customers who told us that we deserve 6 stars in their feedback.

That said, I don't think the efficiency decreases that much as a result of the chips. And I will not guesstimate how much. What I will do is to promise you a no questions asked complete refund policy. And you are not paying for the cells to be shipped to you. So it's very fair. That shows you how confident we are of these cells.

We were doing wholesale to manufacturers overseas in the past only, and they knew how to do that. We are still preparing for our eBay customer. There are numerous DIY offers on eBay and they should be helpful to you. Also you can go to YouYube.com and search for 'how to make a solar panel' to watch free videos.

We provide matching tabbing wires, bus wires, flux, and solder to our customers for our DIY kit.

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Q1.17: What is the difference between Evergreen Solar Cells to make DIY solar panels and solar cells with small chips?

A: The only difference is that the 'small chips' cells are slightly broken, as the pictures show. On one side of the solar cell, there might be a small breakout of the solar cell, so it's not perfectly smooth. But many of our cells are not that broken, they are quite complete. But all of them have little defects.

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Q1.18: Which side of the cell is positive, and which side is negative? The blue shine face is positive or negative? I check with two Multimeters and it tells me that the blue side is negative. Is this correct?

A:  Yes, the front side (blue) is negative, and the back side (gray) is positive. For most silicon based solar cells, the front side is negative. The blue thing is silicon nitride, an anti-reflective coating. The back side gray material is aluminum paste, with 6 square silver soldering points, all of which are positive.

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Q1.19:  I was wondering what other components I need to buy in order to assemble a complete solar panel. Do you sell these other items? What else do I need to make a complete off-grid power generation system?

A: You will need the following other components:
1) Tabbing wires to connect the cells
2) Bus wires to connect the series sections
3) Flux to help you solder the wires to the solar cells
4) Solder to help add additional bonding needs at the back.

We provide all these items in our DIY kit listings.

You will also need:

5) Junction box to help the wire connectors connect between your tabbing wires and your inverters or charge controllers
6) Depending on your encapsulating techniques, EVA, TPT backing
7) Glass, ideally solar glass, but other types of glass may be the substitute because solar glass is very hard to find and ship. So purchase it at your local Home Depot or other hardware stores.
8) Sealants - you want to make sure that your solar cells are protected against impact and moisture for it to last a long time.
9) Did we forget to mention soldering iron? Get 90 watt or above rated soldering irons.

Items beyond the first 4 will be selectively added to our future offerings. So check back with us soon.

After you have made the panels, then you can put together your off-grid solar system this way:

1) Solar panels that have 18+ volts for 12 volt nominal

2) Charge controller

3) Batteries

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Q1.20: What kind of uses can these cells do for me? For example, could a laptop run off these so that I do not get charged from the electric company? Same with a LCD TV, etc.

A: These cells are very thin and fragile silicon solar cells that you need to solder and string together and encapsulate them in protective films and solar glass - in other words, to be made into a panel so that they can charge your laptop and other electrical appliance.

The basics of solar panels is that there are two types - the high wattage ones are going to be connected to your power grid, the lower wattage panels are going to be used to charge your smaller batteries. The high wattage panels can also be used to charge batteries through a charge controller. When your battery banks are large enough, they can power your LCD TV's etc. without you connecting to the grid.

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Q1.21. How many types of solar cells are out there? Which one is comparatively better and why?

A: There are other different thin film solar cells, but let's focus on the silicon based crystalline solar cells.

There are 4 sub types of silicon crystalline solar cells based on how the foundation wafers are made. Crystalline solar cells are all made from wafers through diffusion, screen printing, firing etc. steps.

1) Monocrystalline cells - these base wafers are made from round single crystalline ingots. These cells are the highest efficiency and are great for high power panels used in places where real estate is limited. Most expensive.

2) Multicrystalline solar cells - wafers were made from square ingots made by casting silicon in directional solidification furnaces. Higher production throughput. Slightly lower efficiency than mono. Slightly lower cost.

3) String ribbon solar cells. Evergreen solar cells are made from molten silicon pulled upward by two carbon strings and a long silicon ribbon is formed. They are cut into wafers. Least amount of silicon kerf loss. Lowest materials cost. Slightly lower efficiency than multicrystalline solar cells. Lower cost.

4) EFG wafers - wafers were made in silicon fashion as string ribbons but a big octagon hollow pipe is pulled upward instead of a string ribbon. The pipe's walls are cut into wafers. Efficiencies and costs are similar to string ribbon.

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Q1.22: Whatís the difference between series and parallel?

A: Series connection increases voltage, and parallel connection increases amperage. Series connection is recommended for most panels with 72 solar cells or less. Leave the voltage regulation and conversion to your charge controllers or inverters. If you are going to put a lot more cells than 72, then use a combination of series, then parallel of the series on your panel.

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Q1.23: I purchased 100 cells from you a month or so ago and really need the tabbing wires, flux, and solder to assemble them. Can I purchase these accessories separately and for how much?

A: Yes. This can be purchased separately. Please write an email to info@everbrightsolar.com with your name, quantity, and special comments (if any) to for custom quote.

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Q1.24: I was looking for some tabbing wire and the description had this in it:

"For the Evergreen cells that are now so prevalent the problem isnít the wire used, it is the cells themselves. They simply should not be for sale for DIY use due to their fragility. They are the thinnest cells on the market besides some Belgian multi contacts and are for MACHINE ASSEMBLY. If you hear a crunch when soldering, that is a micro crack forming and has rendered the entire string of cells basically useless as it will create a pooling point for the electricity and will heat up a panel at those junctions, eventually becoming a fire hazard. It may take year or two for it to surface but the panel will eventually fail and be underpowered-long after most of these people will be in business."

Is this true?

A: 1) Poor workmanship can lead to poor panels. That's true. In general we recommend that DIY panels be used in off-grid applications, and leave the grid-tied applications to the panels that are professionally built and UL certified.

2) Almost ALL solar cells made today are about the same thickness as Evergreen cells, and in fact Evergreen cells are even a bit on the thicker side compared to the mono and multicrystalline cells. Why am I qualified to say that? Our company owns a wafer slicing factory in China and we make wafers that are the basis for solar cells! So this whole talk about Evergreen solar cells being the thinnest is just either pure ignorance or a politically motivated smoke screen.

3) The cells that are thicker than Evergreen are Schott solar cells, but they just announced that they are going to shut down the plant in MA. Those cells are so small (4x4) they are just no economical to make any more. That's why Schott Solar shut it down.

4) A majority of the solar panels made in the world are made manually. Machine assembly is only done in Europe and their solder failure rate is astonishingly high and that's why practically all solar cells are soldered manually in Chinese factories. Manual solder is actually more secure and better than machine assembly. It can't be done manually in Europe because labor is too expensive. Suntech and other big companies in China have machine stringers but they are just for presentations and displays, showing how advanced they are. But the real production is done manually. And they solder the cells that are thinner than Evergreen solar cells, and arguably, more fragile because they are all 5x5's.

5) Micro cracks are bad, I agree. If crack happens, remove the cracked cells and fix the whole string. That's why you need to check each string for power before you connect the strings and encapsulate the solar cells.

6) Tabbing wires and bus wires do matter for the right resistance reasons.

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Q1.25: I see your tabs are rated at .5 volt@3.5amp. Do you supply 12v. cells and at what amp? Would this rating be easier to work with 12v storage batteries than the lower rating?

A: Single 12 volt solar cells do not exist in this world. Almost all silicon based solar cells are 0.5x volts each. You get to 12 volts by connecting 24 solar cells in series.

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Q1.26: Are these grade A solar cells? You show 36 cells = 18 volt = a 12 volt panel. All of my 12 volt panels are 22 Volt open circuit. Would 36 of these cells give me 22 volt open circuit to match them or would I need more cells per panel?

A: These cells are our grade A cells with minimal or no blemishes. The open circuit voltage should be on the high side of .5x. Your 12 volt panels (nominal?) perhaps are made from another kind of cell, maybe monocrystalline solar cells. These 36 cell panels should be able to match those, but we recommend that you use panels made from the same type of cells.

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Q1.27: What is the difference between the USA and Germany cells. Which one should i purchase and does pretabbed mean that the wires are already connected where the other ones i would have to connect myself?

A: The ones from USA are untabbed. You have to solder them yourself. The benefit is that these cells have the highest power and it's harder to break during packing and unpacking. The downside is that you need to do a little more soldering work, but it's not hard to solder. Simply use the flux pen to trace the bus bars and flux will on on the bus bar and soldering is a breeze. Use a 90 watt iron. The pretabbed ones from Germany save you a little work, but you have to solder the back side any way. And it's easier for them to break during unpacking. You need to be ultra careful.

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