RV FEATURE |
REALITY
The solar industry promotes
the product's output using
the same Standard Operating
Conditions (SOC) as for its
laboratory testing. That testing,
however, emulates that
only achievable atop a high
equatorial mountain at
midday in midwinter.
Solar module reality is the
industry’s Normal Operating
Cell Temperature (NOCT).
This is typically 71% of that
seemingly claimed. The
makers accept that the SOC
is misleading but state it is
‘historical industry practice’
— as if that somehow
justifies it. The NOCT
is, however, usually
revealed in the technical
specifications, and
even on some modules
but in obscure
technicalities.
MYTH 3
Solar modules produce the
wattage claimed at any time
they are in the sun.
REALITY
Solar modules only rarely
produce that seemingly
claimed in actual usage.
Even that NOCT output is only
realised during the two/three
hours either side of midday in
Australia’s summer. Outside
those few hours, they will still
generate some output — about
another 10% or so. (In a few
rare places — typically bright
sand or within a kilometre
or two of the sea — solar
radiation can be received
directly but additionally by it
being reflected from the sand
or water up to scattered white
cloud and down from there.
This can add 20% or so but
usually only for a few minutes.)
MYTH 4
A solar module loses much
of its output unless it faces
north and is at roughly the
same angle as your latitude.
REALITY
For the highest yearly
average, solar modules
should face north and at the
same angle as your latitude.
However, if you wanted
more over winter, angle
them such that they face
into the sun at midday, i.e.,
more vertical, and vice
versa for summer.
For typical RV travelling
of ‘following the sun’,
horizontal mounting
is fine. Anywhere north
of Geraldton-Brisbane,
this actually results in
higher output most of
the year than if angled.
gorv.com.au
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