Now available - Ultra high power 6x6 mono crystalline solar cells!
These are Grade B 6X6 solar cells with very small edge or corner chips or breakouts. Mono crystalline solar cells are the highest efficiency silicon solar cells on the market today. Compared to other 6 inch mono cells, these solar cells have three bus bars on the front and back, instead of two. These solar cells have never been used.
I: Solar Cells: 144 tested mono 6x6 untabbed solar cells
The standard cell specifications are the following, though the individual cells can be above or below these standards.
Rated power : 3.8 - 4 Wp
Open circuit voltage: 0.610v -0.621v
Short circuit current: 7.65 amp -7.95 amp
Operating voltage: 0.519 v - 0.528 v
Operating current: 6.12 amp -6.44 amp
Dimension: nearly 6 inches by 6 inches or 156mm by 156mm
Weight: Just above 6 grams, or 0.2 oz.
II) Tabbing Wires: additional 450 feet of tabbing wires to connect the solar cells. Cut them into 12 inch sections to solder onto the bus bars or back side of the cells.
III) Bus Wires: additional 45 feet of bus wires. Use them to connect between the series and connect the tabbing wires ends to the junction box at the back of the panel.
IV) Flux Pen: an easy-to-use flux pen that dispenses flux onto the bus bar or your tabbing wires without leaving a mess. It's used to aid soldering and bonding of the wires to the cells. A must have item. The flux liquid in the pen has a seal. At first use of the brand new flux, remove cap, hold the flux and point the tip upward, press the tip inside a few times so that the liquid can flow to the tip later on.
V) Diodes: 4 diodes rated at 15 amp each. Schottky style diodes.
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.
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.
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. You will 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. 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.
3) For a lot higher voltage panels and configurations and connecting multiple panels to get high voltage, consult a professional. Remember that solar panels are always loaded with electricity when exposed under the sun. At high voltage even a tiny bit of current, when handled wrongly, can kill you.
Soldering: If you want to become a serious panel maker, buy a good soldering iron whose temperature can be adjusted. If you can't buy an adjustable solder iron, get one that's rated at 90 watts. When you solder, all you need to do is to apply flux on the bus bars and the backside contacts before soldering. Do NOT scrape off the whitish substance on the bus bar or the backside square contacts. Those are made of silver and must be kept intact. Just apply flux and solder the tabbing wires. The wires are already coated with tin solder so you don't need to use extra solder AT ALL. Use a smooth and continuous motion to solder the wires onto the bus bars of the cells.
Solar cells are very fragile so be very very careful when handling them. Out of all the solar cell packages that we have sent, broken cells via transit are relatively rare occurrences. We make sure that the cells are well protected by a combination of foam pads, paper pad, bubble wraps, inner box, and outer box. Our warehouse personnel take great pride in their packaging.
Each package is clearly marked and labeled with how many inner packs and how many cells there are in each pack.
You might break some cells during the panel making process, so we always give our customers extra bonus cells for free.