PV Gap

Floyd Said:

Can Solar Panels be Charged by CFL lights?

We Answered:

Homebrewer isn't quite right. The figure given for the efficiency of solar panels is usually for the Sun's spectrum.

CFLs peak at a few specific wavelengths. Depending on the bandgap of the doped semiconductors used in the panel, it might be more or less efficient at converting CFL light into energy.


However, you can't run a CFL off a solar panel powered by the same CFL. Think of the energy flows - some of the light from the CFL goes into the panel. Some of this is converted to electricity*, then you lose some of the energy in the resistance of the wires. You'll get back less energy than you had to start with, but the panel will generate some electricity from the CFLs.

This is an example of the second law of thermodynamics.






*you lose some - if the photon doesn't have enough energy to excite an electron you won't get any electricity. If it has more than the bandgap, then you may create an exciton and phonons, and the phonons carry away energy you can't use. And there's always a chance you won't separate the charges in time to use them as current...

Joseph Said:

Solar Panel Voltage Question?

We Answered:

The solar panels should have the same output voltage. If you wire them in parallel, I doubt that the 34 cell panel will add any current to the output. Do the solar cells panels have about the same output current? If so you can hook them in series to increase your output voltage. If not then you should remove 2 cells from the 36 cell panel so that both panels have 34 cells, then you should be able to hook them in parallel and the output currents should add to give you more power.

See our blog at http://brutuscontry.com/blog