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Welcome to The Open Source Solar Project (OSSP)

The sun is the ultimate open energy source and OSSP aims to help everyone harness it. Solar PV in the developing world has been growing at an exponential rate and has managed to provide energy access to millions of people, unfortunately adequate standards and appropriate training programs have not followed suit. Many equipment vendors and installers have little to no training nor are they subject to any form of regulation and end users often have little understanding of the technology. This has lead to the proliferation of many improperly designed PV systems that not only lead to poor end-user experiences but also represent a safety risk. This website is an effort to improve small-scale battery-based (SSBB) solar PV system design, safety, and user experiences in these areas by providing appropriate information, resources and tools on the universal, basic aspects of off-grid system design and installation in these contexts. OSSP hopes to serve as both a direct resource in these areas (via smart phones and internet in hub cities) and as a readily-adaptable base for the development of low-cost training materials and programs that are tailored to the needs and standards of a particular area. Please reach out to alex@opensourcesolar.org if you are interested in collaborating, have found mistakes, would like to contribute or need assistance creating training materials.

Aims of OSSP:

• Provide an appropriate level of detail for each topic in a way that is practical and accessible for an audience with a varying level of technology literacy.
• Present universal concepts in a way that is universal. Information or resources that are location specific should be added to a country page.
• Utilize well-designed graphics that include minimal text to enable easy adapatation and translation using captions.

Be advised that design, installation, and maintenance work should only be performed by qualified individuals in accordance with local codes/laws. There is no guarantee that the information provided on this website is accurate or complete - use it at your own risk. It is intended to serve as an educational/reference resource and not intended to qualify anyone to perform any type of electrical work. Appropriate hands on training is required in order to safely work with electricity and PV systems.

Consult the User's Guide for information on using the wiki software.

Basic concepts

• What is an off-grid (stand-alone) PV system?
  
• Types of PV systems
  
• Basic stand-alone PV system components
  
• Electricity and energy
  
• Types of electricity
  
• Voltage and frequency by country
  
• Power flow between components
  
• Series and parallel
  
• Electrical codes
  
• Electrical safety
  
• Multimeters
  

System components

Certifications and ratings

• Equipment certification
  
• Weather rating
  

PV source

• PV module (PV source, solar panel)
  
• Insolation (peak sun hours)
  
• Tilt and azimuth
  
• Shading
  
• Module connectors
  
• Combiner box
  

Energy storage

• Energy storage
  
• Lead acid battery
  
• Lithium-ion battery
  
• Shunt
  

Charge controller

• Charge controller
  

Inverter

• Inverter
  

Power distribution

• Distribution panel
  
• DIN rail
  
• Busbar
  
• Wire terminal
  
• Twist-on wire connector (wire nut, marrette)
  
• Switch
  
• Outlet
  

Mounting system

• Mounting system
  

Conductors

• Types of conductors
  
• Conductor size
  
• Wire color
  

Physical conductor protection

• Conduit
  
• Junction box
  

Protection devices and disconnects

• Overcurrent protection device (OCPD)
  
• Disconnects
  
• Residual current device (RCD or GFCI)
  
• Ground fault protection device (GFPD)
  

Grounding

• Grounding system
  

Loads (lighting and appliances)

• Lighting
  
• Energy efficient loads
  
• Low voltage disconnect
  
• DC-DC converter
  

System design

• Design process overview
  
• Stand-alone system configurations
  
• DC system voltage
  

Simplified system design process

1. Simplified physical evaluation
2. Simplified load evaluation
3. Simplified weather and solar resource evaluation
4. Simplified energy storage sizing and selection
6. Simplified PV source and charge controller sizing and selection overview

6a. Simplified minimum PV source size

6b. Simplified PWM charge controller sizing and selection

6c. Simplified MPPT charge controller sizing and selection

7. Simplified inverter sizing and selection

Detailed system design process

Background

• Voltage drop
  
• Surge loads
  
• Power factor
  
• Duty cycle
  

Site evaluation

• Site evaluation process overview
  
• Load evaluation
  
• Physical evaluation
  
• Weather and solar resource evaluation
  
• Load and solar resource comparison
  

Design parameters

• Design parameter overview
  
• Irradiance safety parameter
  
• Continous duty safety parameter
  
• Low voltage disconnect parameter
  

Energy storage sizing and selection

• Energy storage sizing and selection
  

PV source and charge controller sizing and selection

• PV source and charge controller sizing and selection overview
  
• Minimum PV source size
  
• PWM charge controller sizing and selection
  
• MPPT charge controller sizing and selection
  

Inverter sizing and selection

• Inverter sizing and selection
  

Wire, overcurrent protection, and disconnect sizing and selection

• Wire, overcurrent protection, and disconnect sizing and selection

Grounding system sizing and selection

• Grounding system sizing and selection
  

Design examples

• Detailed DC system design
  
• Detailed AC/DC system design
  
• Detailed AC system design
  

System installation

• Principles of installation
  
• Equipment clearances and safe working space
  
• Wiring practices
  
• Wiring basic load circuits
  
• Battery wiring
  
• Installing module connectors
  
• Charge controller programming
  
• Inverter programming
  
• Labeling
  
• Commissioning
  

Operations and maintenance

• Troubleshooting

Resources

• Resources
  

Country pages

• Peru
• United States