Understanding Solar Electric Power - Nature Power Solar Generator 1800 User Manual

1 . UNDERSTANDING SOLAR ELECTRIC POWER

Understanding the specifications and operational characteristics of your solar powered electrical back-up
system will help you obtain the maximum utilization and enjoyment from it. All solar electric power systems
depend on batteries to supply the bulk of the power delivered to the user. The primary function of the solar panels
is to charge the batteries. While some small electrical loads may be supplied directly from a solar panel this is
usually not practical.
Solar panels do a very efficient job of converting sunlight directly into electrical energy. The caveat is that as
the intensity of light falling on the panel changes so does the electrical voltage and current supplied by the panel.
Most electrical appliances need a reasonably well regulated voltage and current supply to function correctly. In
order to provide this an electronic regulation device known as a solar controller is used in conjunction with
batteries. The batteries serve to provide a constant source of electrical power when the level of light falling on the
solar panels is too low to provide sufficient power. The solar controller acts like an intelligent battery charger
supplying solar energy to the batteries when it is available to keep them charged up. The solar controller also
monitors the state of charge on the batteries to keep them from becoming over charged.
Most modern appliances run on AC (alternating current) electric power. Unfortunately, batteries, which are
capable of storing electrical energy, cannot supply AC power. They are only capable of supplying DC (direct
current) electric power. Another electronic device, called an inverter, is used to convert the DC power from the
batteries into AC power to run the AC appliances.
So at night or any other time that there is insufficient light for the solar panels to produce power the batteries
continue to supply power until they are totally drained or the light returns and the solar panels start to recharge
the batteries. Since the usable power is always provided by the batteries it is possible to use the batteries power
faster than it is being replenished by the solar panels. In this case the batteries will eventually become drained
even though the solar panels are trying to charge them.
In simpler terms, the battery acts like a barrel of water with a spigot at the bottom. The barrel can continue
to supply water out of the spigot as long as water is being poured into the top of the barrel at least as fast as it is
being drained out of the spigot. But, if the spigot is opened up to the point that it is draining water out faster than
it is being poured into the top the barrel will eventually become empty.
So while a solar electric system uses an endless source of energy, it can only access that energy at a rate fixed
by the size of the solar panels. It can also only access that energy during the hours of the day that sunlight actually
falls on the solar panels. However, the batteries can store a fixed amount of the energy for use while the panels
have no access to sunlight. The size (Amp-Hour rating) of the battery determines the amount of energy that can be
stored.
Thus, any user of a solar electric power supply system must experiment a little to determine the balance
between how much power he can use while the system is charging from the solar panels and how much power
must be stored for use during the evening and night time hours to meet his personal needs.
The power rating of any solar electric system tells you the maximum amount of power the system can supply
at any given instant in time. The size of the battery/batteries determines how long the system can supply that
amount of power. The owner/user should study the systems "runtime charts" to understand how long the system
should be able to supply any given appliance or combination of appliances. The size and type of chemistry of the
battery in conjunction with the size of the solar panel array determines how fast the battery can be charged by the
sun alone. A system that is intended to be portable, such as the
weight of equipment that can be easily handled. More powerful solar electric systems are usually stationary
installations due to the necessary size and weight of the equipment. Whole house solar electric systems usually
have battery banks that weigh hundreds, and sometimes even thousands, of pounds.
Please contact Nature Power Products to acquire more information:
1-800-588-0590
info@naturepowerproducts.com
www.naturepowerproducts.com
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is limited by the size and