TEMPERATURE AND LIGHT LEVELS
In support of the suggestion in section 8. ELECTRONICS that an electronics unit can
be set at a compromise voltage and only be a few % off maximum power. The following
data has been prepared.
Firstly how does maximum power voltage change with light intensity.
A Solarex SX 10 panel was tested at constant panel temperature of 25 Deg C but at
various light levels, the results are graphed below. (Tests conducted in sunlight)
From the graph it is apparent that it is possible to set your electronics unit to a
compromise voltage and not change it unless the Sun level drops below 15%, or your
panel heats up. With the Solarex panel characteristics graphed above and the correct
compromise setting chosen you need only be a couple of % off maximum power setting.
To further add confidence to the argument that being a little bit off the exact voltage
setting only makes a small difference to performance, a dynamometer test was performed
with the same Solarex SX 10 panel an electronics unit and a Faulhaber 2232 6 Volt
motor. The voltage settings for the tests differed by more than “a little bit” see the graphs
below.