Hi I’m Amy from the altE Store. Solar panels
are quite an amazing technology, with the
ability to turn sunlight into electricity.
How on earth (and in space) does it do that?!?
The most common type of solar panel used these days on homes and businesses are silicon based.
These solar panels are made from melted silicon rocks.
A little bit of a positive chemical element,
such as boron, is added to the silicon to
make sure the resulting silicon block, or
ingot, has a positive potential.
Once the silicon has cooled for days and hardened,
the ingot is then sliced into thin wafers,
and the wafer is coated on one side with a
negatively charged element, such as phosphorus.
The combination of the positive boron infused
silicon on one side and negative phosphorus
on the other side creates a positive/negative,
or P/N, junction.
This is where the magic happens, the photovoltaic
effect.
Wires are then painted onto the wafer, providing
a method to harness the flow of electricity.
At this point, the wafer is a solar cell.
When the sun hits the negative side of the
solar cells, some of the negatively charged
electrons are knocked loose from their atoms.
They travel across the P/N junction to the
positive side, where there are holes available
for them to settle into.
This creates a direct current, or DC, flow.
This current is measured in amps.
Simultaneously, a voltage potential is created
between the two sides of the solar cells.
Each solar cell is capable of generating about  ½  volt.
Well ½ volt doesn’t do all that much for
you electrically, so several of them are wired
together in series, plus to minus, to create
a usable voltage.
A typical 12 volt solar panel, like we have
here has 36 of these cells in series, generating
about 18V Vmp.
A 20 volt solar panel like this, that is commonly
used in grid tie home solar systems will usually
have 60 cells wired together for 30 volt Vmp.
Here I’ve got two 24 volt panels, the altE
24V 100W and 200W.
They both have the same number of cells, 72,
but this one is only 100 watts, and this one
is 200 watts.
You can see that each cell in the 200 watt
solar panel is twice as big as the cells in the 100 watt
solar panel, so it is putting out twice the
current, or amps.
Since volts times amps equals watts, twice
the amps means twice the watts.
Multiple solar panels can then be wired together
in series to further increase the voltage,
which is then called a series string of panels.
Multiple strings of panels can then be wired
together in parallel, to increase the current.
Multiple solar panels all wired together make
up a solar array.
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