Please note: these 3x6 string ribbon type solar cells have been tabbed, but tabs have been clipped, leaving the tabs on the bus bars but both remaining tabs still have a short end that still protrudes out beyond the edge fo the cell. So there are two ways you can use these cells:

A) Simply apply flux on the end of the tabbing wires where they are cut off, and solder another section (3 inches long) of the tabbing wires to lengthen it. Typically you don't need to add extra solder becasue the tabbing wires that we provide are already coated with tin solder. So, flux and solder.

B) Use a soldering iron to heat up the wires and gently remove the clipped tabbing wires, and then apply flux and solder another full 6 inch long tabbing wire.

These cells are really very good and very wholesome cells. Some tiny chips are possible, but they are very rare in this category. Because the tabs have been clipped, we rate them A-.This set of new 3"x6" solar cells are string ribbon multi crystalline cells made by a reputable and major world class solar manufacturer, and the cells have the smallest carbon foot print - they waste the least silicon in making these cells. The cells are the original factory standard cell size. The cells have never been used on panels, but they have tabs being soldered on the front side. 

I: Solar Cells:

The factory standard cell specifications are the following (under perfect testing conditions), though the individual cells can be above or below these standards.

Cell Specifications: 
Average Power (Watts): 1.75 W 
Average Current (Amps): 3.5 amps 
Average Voltage (Volts): 0.5 V 
Thickness 200 μm = 0.2 mm 
Exact dimension: 3 1/4 inches x 6 inches, or 80 mm by 150 mm 
Weight: Just above 6 grams, or 0.2 oz.

Some useful information in making solar power:

How to make sense of the above numbers:

The basic and very important formula you need to know to make sense of solar cells is this: Power (P) = Current (I) Multiply by Voltage (V), or P=I*V Power's unit of measure is watt, 
Current's unit of measure is amp, 
Voltage's unit of measure is volt.

So in our solar cell's specific example, if each solar cell is rated at 1.75 watts on average, and the voltage is 0.5, you do a little algebraic math, then to get the amps (I), since P=I*V, so I = P / V , therefore I (amps) = 1.75 watts divided by 0.5 volts = 3.5 amps.

It's important to understand the concepts of series connection and parallel connection when stringing these solar cells together to make a solar panel. 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 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 cell in the same set. You can use a combination of series and parallel connections to get the right voltage and amperage for your solar panel.

The cell specifications above were given to us by the manufacturer as averages. Variations are possible. To make a 18 volts panel, for example, you connect 36 cells in series (36 cells times 0.5 volt each = 18 volts). And 36 * 1.75 (each cell in theory averages 1.75 watt) watt = 63 watts. The amps you will be getting is 63 watts divided by 18 volts = 3.5 amps.

Solar cells basics:

The front of the cells (blue side, aka Sunny side) has two thick white lines, called bus bars. They are the negative terminals of the cell. The back side, where the 6 square dots are, are positive terminals. Connect the tabbing wires from the bus bar of the first cell on one side to the three dots of on the back side of the next cell. That way you have a series connection. Repeat the process on the other side of the cells. In panel making you should connect all the tabbing wires on the front for all the cells first, then flip the cells over to solder the back side in a second step. Some solar cells such as SunPower cells have both positive and negative terminals at the back of the cells, but we don't have to worry about them. Most cells are negative on the front and positive on the back.

The white color bus bars on front and the contact points on the back are made out of silver, and you should keep them intact. Apply solder on your them and the wires should bond.

Testing:

Make sure that you test the cells under strong sun light with the front of the cell facing the sun, at the same time connect your meters to the right terminals. If you are inside the building, make sure you shine your sun simulating lamps onto the front of the cell while testing. Place the solar cells on a metal plate, ideally made from copper. With a warm light (ie halogen lights) shining on the cell, put your positive lead from your multimeter on the plate, and the negative lead of your multimeter on the bus bar. Your multimeter will be set to typically check amps or voltage at one time.

Panel configuration:

For those who are new to solar panel making or if you don't have an engineering background, here is our recommendation:

1) Make small panels first so you gain experience.

2) In most situations, make either 36 or 72 cell panels, and connect them in series. 36 cells give you 17.5 or around 18 volts or so. And 72 cells doubles that. These panels are very useful, and you will find a lot of matching products that will want to buy! For example, you almost always want to use a charge controller if you make your panels to charge batteries. Charge controllers usually come in 12 or 24 volt settings, which match your panels' 18 and 36 volts very nicely. Yes, your panel voltage should be 1.5 times the voltage of the battery you intend to charge. Connect more panels together if you want to tie to the grid, in which case, always use an inverter. However, we always recommend that the panels that you make for yourself be used in off-grid applications, such as charging your batteries to be used in RV, remote cabin, or marine settings. If you intend to connect to the grid, it is wise to buy the professionally made, UL certified panels.

3) For a lot higher voltage panels and configurations, consult a professional. Just don't fry yourself.

Soldering:

If you want to become a serious panel maker, buy a good soldering iron whose temperature can be adjusted. Don't get a cheap iron. It's one of the most important tools you need to have. Get those that have a flat soldering tip / head.

Packaging

The solar cells are very fragile so be very very careful when handling them. But out of all of the solar cell packages that we sent so far, broken cells via transit are relatively rare occurrences, though theoretically it's quite possible. We invested a lot of resources to make sure that the cells are well protected by a combination of foam pads, paper pad, bubble wraps, manufactured foam forms, inner box, and outer box. 


You might break some cells during panel making process, so we always give our customer extra bonus cells for free just to show consideration for our customers.