Stand Alone Off Grid Solar PV System
Stand-alone systems are independent from the utility grid, avoiding the
possibility of losing
power when the grid goes down. Electricity from
stand-alone systems are used on site, such
as an RV or cabin. Power that is
generated can be stored in batteries and used at night or on
sunless days. A
generator may also be used for back-up. For PV applications, the size of a
stand-alone system is usually up to 50kW.
Typical off grid solar PV system diagram:
Off Grid Solar PV Systems Include:
1. PV Array: A number of PV panels connected in series and/or in parallel
giving a DC output
out of the incident irradiance. Orientation and tilt of
these panels are important design
parameters, as well as shading from
surrounding obstructions.
2. PV controller: control battery bank charge and discharge reasonable and
safety.
3. Inverter: A power converter that "inverts" the DC power from the
panels into AC power.
The characteristics of the output signal should match
the voltage, frequency and power
quality limits in the supply network.
4. Battery bank: can be a single battery or multiple batteries connected
together to create essentially one large battery of the required voltage and
amp-hour capacity. In some ways
the battery configuration and capacity are
the most important electrical power decision to make,
and a wise choice can
help guarantee a steady supply of electrical power as well as a system that
is simple to operate and maintain.
5. Loads: Stands for the network connected appliances in the building
that are fed from
the inverter, or, alternatively, from the grid.