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Question:

Numbers behind Solar Panels?

Okay, I think I understand what I'm doing, but I want to set up some solar panels on the roof of my garage, the building that gets the most sun, and I want to make sure all my math is correct in determining number of megawatts per year. However, my knowledge of electrical terms in quite n00bish, to say the least.Here is what I think I should be doing.The solar cells come at .75 Watts average power.I will install 4 panels of 64 cells each, with a total of 256 cells.

Answer:

For comparison, 36 of these make a normal 2V x 50W panel. Note they are not tabbed. This means you have to find a way to connect them yourself. The tabs are probably spot welded on by the suppliers. A supplier below has kits of these with tabs, as needed to connect them together. These are not suitable for grid connect, because the higher voltage needed makes do it yourself panels a dangerous and litigious thing to have on your roof. Maybe you could buy a smaller pack from the link below to compare tabbed and untabbed and work out what to do. Your power calculation is a bit incorrect because the sun is only present some of the time. The 36 cell module would produce 50W when square on to the full sun. The sun may be out for around 2h a day in some places and times of the year. However it is the equivalent of 5h full sun, because of the changing angle throughout the day. Look this up on the internet for your region. Temperate zones may be a lot less. One pack in your link is 36x3 = 08 cells. Thus 50W per pack x 5h a day gives 750Wh per day and 274KWh/y. In reality it will always be less because of regions, weather, clouds, dust, inefficiencies, aging of cells.

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