by two key incentives: one is
the desire to get hands-on ex-
perience, which can help pro-
the other is to save money. These are laud-
able goals, but the latter can lead to some
big mistakes when people try to save
money in the wrong places. I'm going to
outline several areas where I have seen
dangerous and dumb and the how and
why.
give good exposure to the sun. True south is
the correct orientation. If you use a compass
to find south, be aware that compass south
is not true south. True south is actually
about 18 degrees east of compass south in
the Cariboo. PV panels should be as per-
pendicular to the angle of the sun as possi-
ble. This can be accomplished using a
mount that can be adjusted seasonally, but
if that's not possible then a reasonable com-
promise between the low sun angle of win-
ter and the high angle of summer should be
considered. In a cabin where the most en-
ergy is required in summer months, a flatter
angle is permissible; but, in a year round
residence winter sun energy is more pre-
cious and an angle that favours the winter
sun should be considered.
hold on to them in high winds and extreme
conditions like ice and snow loads. Com-
mercially available frames are made of alu-
minum--the same metal as the solar panel
frames. Using an iron structure can lead to
what is called galvanic corrosion and seri-
ously deteriorate the panel frames over
time.
they lose efficiency so it is important to
mount them on a structure that allows at
least two inches of airspace below the
panel. The other consequence of excess
heat is the deterioration of electrical insula-
tion and delaminating of cells, leading to
the possibility of failure or fire. My favour-
ite method of mounting panels is on a pole
mount because you virtually eliminate these
problems. The next choice is a ground
mount if you don't have issues with vehicu-
lar traffic, domestic or wild animals, and
security. Both of these solutions are easier
to keep clear of snow than roof mounts.
sized. An undersized cable will bleed en-
ergy in the form of heat and at the least will
cost you a percentage of your investment
and at the worst will be a safety hazard.
Consult wire size tables in the product man-
ual or online. The total potential output
amperage needs to be considered, taking
from pole to pole it will be a different wire
than if it is buried in a conduit or running
across the surface of a hot roof or open yard
area.
biner and breaker boxes usually have a
selection of circular knockouts of different
sizes. Using a hammer and punch, knock
out a circle of appropriate size to run the
wire into the box. Install a strain relief in
that hole, matched to the cable size, and it
will clamp down on the cable so that it isn't
just hanging loose. Not using a strain relief
leaves an opening where insects, moisture,
and even mice can get into the box, not to
mention that the wires hanging out of the
box can be subject to strain, accidental dis-
connection, can rub against the edge of the
knockout and short, and any number of
other nasty scenarios.
without strain reliefs; there was even a va-
cant hole where a knockout was removed.
Where the strain reliefs should have been
there were just wires going into the box.
This small 8"x10" box was stuffed full
of... wait for it... dog food! The resident
owned several dogs and open bags of dry
dog food pellets were lying around. An
enterprising mouse had packed the breaker
box absolutely full of the pellets; it was
kind of like a mouse safe. It was also a fire
waiting to happen. Ants and other insects
can also short out circuits and destroy
equipment.
kind of a screw lug or compression screw
you need to understand the term "copper
creep." Although that is a perfect descriptor
for the thieves who steal copper wire and
pipe, it is not what we are referring to here.
Copper and aluminum are soft metals and
although you tighten a connection screw
securely, the malleability of the metal will
cause it to flatten out under pressure and
the connection can actually become loose.
This doesn't happen immediately, but may
happen within a few hours or days so it's
always good practice to check and re-
tighten connections. I've found loose con-
nections on many installations over the
years and these will cause arcing (a nasty
flash of pure energy that can cause fires
especially in the presence of dung beetle
scat) and carbonizing of contacts, which
will reduce the flow of energy and cause
heat leading to equipment failure and the
aforementioned fire.
due to energy surges. In at least two of
those instances the problem was lightning.
The tremendous energy contained in a
lightning strike can actually carry for sev-
eral miles along power lines or even
through the ground. While it is more likely
that a nearby lightning strike will cause a
problem, don't ignore the potential of the
longer range. It's something like a person
with a cold sneezing in a room; the germs
travel along vectors that are invisible and
yet very real. There are several things you
can do to protect against lightning like
ers and PV arrays including each solar
panel and the racking; ground the equip-
ment boxes; and, install surge arrestors on
both the AC and DC circuits. Microcircuits
in equipment including computers, TVs,
stereos and many modern appliances are
very susceptible to power spikes. The cost
of equipment repair or replacement is much
higher than taking precautions ahead of
time.
are connecting solar panels of dissimilar
voltages and connecting batteries of dis-
similar types. In either case an imbalance is
created that will cost potential energy and
waste money.
battery bank. Let's say you have a set of
batteries at your cabin and you've discov-
ered that you don't quite have enough stor-
age capacity for your needs. The existing
batteries are three years old so you go out
and buy another set to parallel with the old
set, hoping to double your storage. What
you have just done is throw away two to
three years of the life expectancy of the
new batteries. Yes, you will get more over-
all storage capacity, but you end up averag-
ing the total life expectancy of the set. If
set of batteries do it within six to nine
months, depending on the quality of the
original set.
same voltage and don't tap off a set of bat-
teries within a set to power a secondary
device. This can happen when, for example,
you have a 24v battery but need 12v to
power an appliance like a phone or light.
The tapped batteries will age much more
quickly and imbalance the charging of the
set. A variety of consequences can result
from sulphation to thermal runaway if a
cell in a battery fails. The better solution is
to get a 24v to 12v converter that draws off
the entire bank.
thoughts all sunny.
our website:
Ron Young is a Renewable Energy profes-
sional operating the earthRight store in
Williams Lake, BC selling and installing
RE systems
Ron
Young