Stand Alone Solar Power system or Battery-Based
Solar Power system
A battery based home power system could be the
first choice if you are building in a remote location or where the
utility is more than 400 metres or so distant from the home. It also
maybe that you have decided the utility has become a big nuisance where
you are paying a daily fee, sales taxes, suffering power surges,
outages, living with a smart meter and then you are paying a ever
increasing price for your electricity. It will not likely save you money
to disconnect, but it might be worth the peace of mind, like growing
your own potatoes. It is not an economics decision, but a choice of how
to take control of the resources that support you.
This is a system where the household electrical
loads are energized by storage batteries and recharged by solar panels
or a generator. An electrical device known as an inverter is usually
used to change Direct Current (DC) battery electrical power into 120
volt Alternating Current or AC unless the dwelling runs entirely on low
voltage DC current.
generation source whether it is solar or other doesn’t know when the
batteries are fully charged so another piece of hardware known as a
Charge Controller is necessary. High quality charge controllers can make
a big difference on efficiency and battery longevity.
With wind turbines and microhydro turbines there
has to be a place to put excess power being generated (dump load) when
the batteries are full or the turbine commences to spinning without any
resistance and that can lead to over spinning and wear. Most household
sized inverters also double as chargers that can regulate the charge
from an AC power source like a generator again to maximize battery
This kind of independent power system is not
connected to any source of utility power. To maintain the batteries
charge homeowners might use one or a combination of the following: a
solar panel array, wind turbines, microhydro turbines, and an internal
combustion engine driven generators (These can be gasoline, propane,
diesel, or biodiesel fueled). Solar is usually paired with a fueled
generator. Wind is not very practical in most valley locations west of
the Continental divide in NW Montana and the Kootenays. If you live in
other areas or happen to be very near a ridge top wind might make-up a
part of your energy portfolio. See Wind
for more info.
A common misconception is that there is not enough
sun here. In the West Kootenays there is on average about 1350 hours of
full sunshine equivalent per year or 3.6 hours per day average. From
November to late February you will find a need to run a generator every
few days or rely on a microhydro system because our sun does not come in
those months as you may well know.
The greatest challenge to those wanting to build or
living off-grid with a stand alone battery based system is to learn how
to live using less power. The 2000 Sq Ft home in Montana we built in
2000-03 used about 3 kW hours a day in winter. The alternative is
bigger battery storage, and big generators, or lots of solar panels in
various balanced scenarios. The problem with this, if not cost, is the
waste when the sun comes back. Once those batteries are full the solar
energy (electricity) stops flowing. It’s like being all dressed-up but
having nowhere to go out.
How to use less power? Eliminate any appliance that
employs resistive load heating. That’s base board heaters, portable
electric heaters, toasters, toaster ovens, Electric ranges and
stovetops, dishwashers with sterilizer and drying cycles, electric
clothes dryers, hair driers. The one place I still find I use electric
to make heat is in a bread maker. I wait for the sunny days to make
bread and bake with the converted and inverted sunshine.
Probably the easiest way to make the transition to
an off-grid lifestyle is to spend a year living in a wall tent or yurt
while you are building your house. By the time you have the house
livable and move in, you will feel like you are living like royalty on 2
kW hours per day.