Left: A plot of the RAWS battery volt-
age. This is used as a proxy for the
amount of power available from solar
panels. However, solar panels put out
increasing current with increasing illumi-
nation while the output voltage is rather
constant (see graph, lower left). There-
fore It is difficult to estimate output
power based only on battery voltage.
This estimate assumes that panels are
putting out full rated current for one
hour for each data point when the bat-
tery voltage is 14.0 volts or higher and
no current below 14 volts. During the
year were 1460 data points at 14 volts
or above. About 500 data points are
missing from the data set, These were
not counted in the estimate.