Your average “conventional household” has an electric consumption that ranges between
3,000 to 5,000 watts. It is possible to run an “off grid household” on 20% of the power
consumption a “conventional household”, with some life style and design considerations.
In general your typical solar power system requires a life style change in power
and understanding how much power each appliance uses and adjusting your use accordingly.
SOLAR SYSTEM DESIGN:
Most solar systems are designed for a period of autonomy (cloudy days with limited power
generation) to which the size of the actual battery bank, solar array and charging system
vary depending on "actual" power demand requirements, site location and number of days
of autonomy that the solar power system is to be designed for. As such due to our long winters
with short solar days the typical solar system is designed allowing for a generator to provide
approximately 20% of the power requirements that the solar system is designed for. A solar system
can be designed to provide 100% of the actual power required, assuming that you
the actual power required as dictated by your power consumption.
A good way to determine the power required as dictated by your power consumption is to:
a) document your appliances power consumption,
the appliance in the power consumption work sheets along with usage.
Better yet to actually determine an appliances power consumption we have a power meter that
you plug into the wall outlet to which the appliance is then plugged into, the power meter then
records the actual amount of power an appliance uses including actual wattage demand and
consumption over a period of time.
DETERMINING ACTUAL POWER REQUIREMENTS:
1) you have to understand that certain appliances draw the same amount of power whether you actually are using them or
have them shut off (appliances with transformers)
such as: a vcr, dvd player, tv, clock radio, etc.
2) you have to understand that certain appliances draw a residual amount of power even if the power switch
is shut off such as: microwaves with clock timers, televisions, stereo systems, etc.
That is why the above listed appliances in 1) & 2) above are usually wired to a switch which physically turn the power
off to the power outlet the appliances are plugged into.
3) replace appliances that require power 24/7 such as: clock radios, smoke detectors, etc.
4) you have to consider replacing inefficient appliances with energy efficient appliances
where ever possible, such as: clothes washers, dish washer (or wash by hand)
5) you can not cost effectively (it is not that it can not be done it is just not “cost effective”)
design a solar system to operate the following appliances: 220 volt dryer, 220 volt range,
hot water tank, geothermal heat pump, electric heat source
(baseboard, space heater, furnace, boiler, etc.).
That is why the above listed appliances above are usually replaced with either propane or
natural gas appliances.
6) you have to consider replacing inefficient appliances with an alternative energy source
wherever possible, such as:
refrigerators, deep freezes, kitchen ranges, etc.
Options for an alternative energy source for the above appliances include, propane,
natural gas, super efficient 110 volt
AC, 24 Volt DC or 48 Volt DC appliances.
SHOP, FARM & LARGE LOADS:
You cannot get a realistic return on investment if you are actually trying to use the system for huge demands such as:
electric watering bowls, welders, shop tools, etc.
In such situations when ther is a large load, it is provided for by either a generator or grid power.
Understand that a DC powered appliance (usually 24Volt or 48Volt) that will run directly off of the DC power panel
(powered by the battery bank) usually consumes less power then a comparable 110 Volt AC appliance (do your research
document the proposed appliance power consumption) as you lose approximately 25% of the power in the conversion of
the power by the power inverter from DC to AC. So a DC appliance 24 Volt 5 amp consuming 120 watts is more “system
efficient” then a 110 volt 1 amp appliance that consumes 110 watts.
Solar systems can be designed to provide 100% of determined “off grid household” power consumption with the intention that a
generator is to be run when using large power equipment; the system has the lighting and small loads for
the shop provided by the solar system.
Essentially if you want to pay for it a system can be designed to provide a
“conventional household” electric system.