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Low cost 5V 0.8W/ 160mA solar cell (HCPOWE0005). Encased and protected by a durable outer poly frame. Copper terminals/pads are provided on the reverse side to allow positive and negative wires to be soldered directly onto the cell.
Max working voltage: 5V
Max working current: 160ma
Dimensions: 85mm × 85mm x 3mm
These solar panels are suitable for small home projects, science projects, electronic applications, charging small DC batteries* and building your own powered models/toys/solar displays etc.
*Note: When charging batteries a suitable diode should be placed in series to avoid the battery driving current back in to the cell if the cell voltage should drop below the battery voltage. Driving a reverse current in to a solar cell can cause permanent damage to it.
Why is the amount of current I get from my solar panel lower than the specification?
The amount of energy a photovoltaic cell can produce is directly related to the amount of energy there is in the sunlight reaching it. As an example let's start by making a rough calculation of the panels efficiency:
When the Sun is directly overhead the amount of potential energy it produces is about 137 milliwatts for every square centimeter of area it hits. For this panel the actual area of the cell is about 7.8 x 7.5cm (rough measurement), which is about 58.5 centimeters squared. This gives the maximum amount of energy that the cell can collect as 8 watts. The manufacturer specs this cell at a maximum output power of 0.8 Watts. This means that the cell is approximately 10% efficient. i.e 10% of the energy in the sunlight will be converted to electrical energy by the cell.
However, the above calculations are based on the maximum possible energy that can be collected from the sun when it is directly above. When taking into consideration the time of day, distance from the equator, and time of year, the sunlight hitting the panel is unlikely to be at this energy level. Let's take for example the UK in mid summer and winter:
In the UK, not being located near the equator, in mid summer, and at high noon we get about 60% (this also varies greatly depending on if you are in Scotland or southern England) of the energy when compared to countries at the equator because the sun is never directly above us. So based on the efficiency of our panel this means that the maximum amount of energy you can reasonably expect to get from the cell in the UK is about 0.48 Watts, or about 96mA
In winter the sun is significantly lower in the sky, and in mid winter the amount of energy can be only a third of what it is in mid summer. This is because the sunlight has to travel through more of the Earths atmosphere and so gets reflected, scattered, and absorbed by water molecules, dust and other pollutants. Based on the above calculation, a third of the amount of available energy in mid summer is about 0.16 Watts, or 32mA.