Three 165 watt
24V panels provide about 2500 watts per day when it's sunny. This
is about the same output as our tiny hydro generator which produces 100
watts continuous in the wet months. This is not a lot of
electricity. Most people size a system based on their use, we
sized ours based on what we could afford!
This is our off-grid
electricity control center, power is fed from solar panels or the hydro
generator to the charge controller (little white box), and then to the
batteries (wood box), and then to the inverter (black box), with
breakers in between everything. The large white box
is our on demand propane water heater, it has been shut off since we
installed wood heated hot water. Our system cost about 10,000
dollars total and provides enough electricity to run lights, computers,
and small appliances.
This is the inside of the
Solar Mini DC combiner and switch box. One of the biggest
problems with installing your own off-grid electric system is component
compatibility. All connections must be made inside code approved,
UL listed boxes, all component connected by conduit. Every
connection must be made in a code approved manner. This seemed
like no big deal until I tried to do it and discovered how difficult it
really was. This innovative and reasonably priced box made it
possible. Above are the connections for solar, things got a lot
more crowded with the hydro disconnects in there.
This is our tiny hydro
generator, purchased from HI-Power
Hydro, essentially a brushless DC motor rigged to run backwards.
We don't have much flow (30gpm) or drop (18psi) so this little
guy only puts out about a hundred watts, but it's enough to carry us
through the winter. In the summer we switch to solar panels
exclusively. Total cost for this system was about 2,000 dollars.
This is the ultimate quick and simple solar hot water
installation. Two salvaged flat plate collectors from the 1970's
sit at a natural angle on our porch roof and the convection drives the
flow of water into the storage tank on the other side of the
wall. In many ways you couldn't do worse than this
installation, the panels are old and full of air leaks with
outdated insulation. The selective glass on one of them is facing
the wrong way! All my copper piping is uninsulated, the panels
are not at an optimum sun angle, and the whole system is undersized for
this climate. Despite all this, they work fantastic! On any
sunny day between equinoxes the water is actually too hot, a partial
sun day gives us good hot water, and a day with light cloud cover will
still produce warm water that takes little extra energy to heat.
In the deep winter trees block our sun, so we'll drain the system and
let the woodstove heat the water, which it will do anyways because the
woodstove is also our cookstove and our home heater.
I could have never imagined how well this simple, cheap system
performs, and even the expensive, efficient solar heater with all the
bells and whistles are not that expensive. It has left me
wondering why everyone doesn't have these on their house? Solar
water will not meet all our needs in a coastal climate but it will heat
at least half the hot water in a year. With the water heater
being the largest energy hog in the house, who wouldn't want to save
half that money?