Solar Panel Update

The solar panel being used is Solar Tech 10W module.  Solar energy was chosen due to it's versatility and size.   The load only draws 187mA per hour, so a small solar panel does suffice to keep the batteries charged.  

Below is a picture of the solar panel blue print from the Solar Tech Data Sheet.



The total energy output from the solar panel on an average day in the winter will be approximately 35Wh.  

To view the calculations for this, click Here.

Below is a map of the PV Solar Radiation during December, in the United States.  Click on the map to go to the National Renewable Energy Laboratory website.  



By looking at the map, Vermont is in the ranges of 2.0-3.0 kWh/m2/day; a good estimate for the average solar energy per day is 2.5 kWh/m2/day for Vermont, in December.  This helped to find the standard deviation of the normal distribution function for sunlight during a 24hr period.  Then the energy output is easily calculated.  

The below graph shows the solar power density of the course of 24Hrs in Vermont, in December.  Click on the graph to view the excel file calculations.



You can see from the graph, that the most solar power will be collected at noon.

Katie Gallo          kgallo@uvm.edu
Tom Lanagan     tlanagan@uvm.edu