PV Gap

Tammy Said:

how can i calculate the efficiency of a 5inch sq solar wafer ? what power /voltage /current it should deliver?

We Answered:

efficiency = output power / input power

The power from the sun on a clear, bright day is about 1kW/m^2. Calculate the area of your cell in square meters. Multiple this area by 1000 Watts, and this is the power your cell would produce if it were 100% efficient. This is the input power.

To measure the output power, you need to measure both V and I at different loads, on a bright sunny day. Make sure the cell surface is perpendicular to the suns rays. The area of the shadow should be maximized. There will be a particular load resistance where you will get maximum power. Take this value of output power and calculate your maximum efficiency. I think a 5 inch sq silicon wafer cell can deliver amps of current, but the voltage would be ~ 0.5V to 0.7V