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.

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Last modified: 03/28/15