Solar Panel

[jswharton]

So I'm looking to add solar and it seems that many folks have mentioned AM Solar in Oregon as a honest dealer. The have a 150 watt panel with these specs

Pmax = 150 watts @ maximum power
Vmpp = 18.5 volts @ maximum power point
Impp = 8.11 amps @ maximum power point
Voc = 22.2 volts @ open circuit
Isc = 8.88 amps @ short circuit
Length = 58" (1474mm)
Width = 26" (660mm)
Depth = 1.574" (40mm)
Weight = 26.4 lbs. (12 kg)
Note: Length is 61.375" with mounts installed

On the other hand Wholesale Solar has an ET Solar model with 300 watts with these specs

Model - P672300WB module 300-watt Module
Watts - 300
Amps - 8.8
Volts - 36.68
Dimensions (inches)- 77.01×39.06×1.57
Weight (lbs) - 50.92
More info @ http://www.wholesalesolar.com/pdf.fo...-P672XXXWB.pdf

Here is the thing I don’t understand, they are priced at about $300, which means twice the watts with the ET panel. Seems like ½ price is good? What am I missing.

Ps – I have room for 2 of the larger panels but am planning to start with 300 watts, I have 300 ah of batteries. Will probably use the Morningstar 60 controller.

Thanks

[Bigboomer]

Scott,

You might want to try Northern Arizona Wind and Sun at http://www.solar-electric.com/

They have some really nice Made in the USA panels from Solar World. I went with three of the SW-270's

[halfwright]

Scott, I think the following cut and paste will explain the difference in the price. The cheaper ET panels are polycrystalline. I ordered all my panels, controller and inverter from Arizona wind and sun. They were the cheapest I could find on the web and were cheaper than local, even with the shipping charges.

Monocrystalline, or Single Crystal, is the original PV technology invented in 1955, and never known to wear out. Polycrystalline entered the market in 1981. It is similar in performance and reliability. Single crystal modules are composed of cells cut from a piece of continuous crystal. The material forms a cylinder which is sliced into thin circular wafers. To minimize waste, the cells may be fully round or they may be trimmed into other shapes, retaining more or less of the original circle. Because each cell is cut from a single crystal, it has a uniform color which is dark blue.

Polycrystalline cells are made from similar silicon material except that instead of being grown into a single crystal, they are melted and poured into a mold. This forms a square block that can be cut into square wafers with less waste of space or material than round single-crystal wafers. As the material cools, it crystallizes in an imperfect manner, forming random crystal boundaries. The efficiency of energy conversion is slightly lower. This merely means that the size of the finished module is slightly greater per watt than most single crystal modules. The cells look different from single crystal cells. The surface has a jumbled look with many variations of blue color. In fact, they are quite beautiful like sheets of gemstone.

In addition to the above processes, some companies have developed alternatives such as ribbon growth and growth of crystalline film on glass. Most crystalline silicon technologies yield similar results, with high durability. Twenty-five-year warranties are common for crystalline silicon modules. Single crystal tends to be slightly smaller in size per watt of power output, and slightly more expensive than polycrystalline.

The construction of finished modules from crystalline silicon cells is generally the same, regardless of the technique of crystal growth. The most common construction is by laminating the cells between a tempered glass front and a plastic backing, using a clear adhesive similar to that used in automotive safety glass. It is then framed with aluminum.

[jswharton]

Good info, thanks. I have not seen many installs and most roof top panels seem to have the panels installed lengthwise, front to back. I was up on the roof this weekend and have 2 spots that a larger panel could be mounted side to side. One is 64" and the other 55", so even with the smaller one there would be 7+"'s between the vents/air conditioners. And there is about 96" side to side.

Doing the install this way would require a higher bracket on the ends to accommodate the roof curvature. I didn't measure but would guess 4-5". Do you think this would present a problem allowing too much wind/lift while driving?

If installed lengthwise, how close to the roof edge cane you get? There is about 48" from a vent or a/c to the roofs edge so with a 39" panel the closer to the edge the less chance for shadows. Thoughts

That's for the info and for sharing!

[halfwright]

I put 4 125 watt panels on lenght ways with mounts that raise them about 1 1/2 inches. I was careful to place them where they could never be in a shadow. Be sure to look at the vents raised. I have room for 2 more length ways and one cross ways in the front.

I would not mount the panels that high. But, this is not based on any facts about wind lift or drag. It is just my opinion which is worth what you paid for it.

[jswharton]

Any one with the names big boomer and halfwright are worthy of lending an ear, and if a Ethiopian monkeybeaver dog is involved, well that just seals the deal!

Thanks guys

[halfwright]

Ethiopian monkeybeaver dogs are really quite rare. I know he is Ethiopian because he is always hungry. And, he eats bananas and tree roots.

Actually, he looks like a homely poodle crossed with an ugly spaniel. He comes from a pound in Lakewood CO. He is almost as smart as a phillips screwdiver. We call him a wonder dog because we are always wondering what he will tear up next.