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poor man's pyranometer

A project log for 1Charger

OneCharger to rule them all; solar-panel, TEG, dynamo...

mrjbmr.jb 07/04/2015 at 06:030 Comments

Most lux sensors has a limited range ( < 100 000 lux ) and I plan a different approach.

Current source current is directly proportional to the solar radiation

Measuring Solar Radiation, Chuck Wright

Measuring Solar Radiation by Chuck Wright

In a solar cell, the parameter most affected by an increase in temperature is the open-circuit voltage -2.2 mV/°C

The short-circuit current, Isc, increases slightly with temperature, since the band gap energy, EG, decreases and more photons have enough energy to create e-h pairs. However, this is a small effect and the temperature dependence of the short-circuit current from a silicon solar cell is

A change form 25 to 50 °C will increase Isc current 1.5%.

The impact of increasing temperature is shown in the figure below



Area [dm²]Isc [mA]Lux0.000079 x lux [Watt/dm²]
0.71 ( 1W panel ) 185.51200009.48

152 935007.39

129764006.03

20.9 143001.13
3.1 ( 5.15w panel )10101195009.44

850 954007.54

730765006.04

610588004.65
5.7 ( 7.5watt panel )15601132008.94

1390 960007.58

1170762006.02

1040611004,83


http://www.pveducation.org/pvcdrom/solar-cell-operation/short-circuit-current

http://www.pveducation.org/pvcdrom/solar-cell-operation/effect-of-temperature

Pyranometers and reference cells
Pyranometers and Reference Cells, What’s the Difference ?

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