Pulse Width Modulation (PWM): PWM charge controllers can be considered an electric switch between the solar panel and battery packs, programmed to only allow a pre-determined current into the battery. The controller slowly reduces the amount of power going into the battery as they approach maximum capacity. PWM Charge Controllers do not adjust voltage, meaning the batteries and panels must have compatible voltages in order to operate properly. This makes this type of charge controller suitable for smaller solar applications, or installations that feature lower voltage panels and limited size battery banks. PWMs are a more affordable option but will result in a lower power production from the PV .
Turn solar to electricity
small solar system
Large power system
- If possible, install panels on roofs of buildings, and in areas where persons do not frequently visit - avoid roof top terraces or resting areas.
- Install solar arrays inside of compound spaces, inside the safety of a perimeter wall wherever possible. Even if arrays are inside a compound wall, there should be some form of signage and barrier fencing to prevent visitors or casual labor labour from accessing the area.
- If solar arrays are installed in the open in remote locations, then a separate security fence or wall will need to be built around the outside. The equipment is expensive, but it can also harm humans and animals passing by. Persons unfamiliar with solar panels may be drawn close out of curiosity, so signage must be posted in the appropriate local language.
- RED R, (2002). Engineering in emergencies
- MEDICINS SANS FRONTIERS, (2007). Electricity Support.
- ENGINYERIA SENSE FRONTERES, (2006). Tecnologías de la energía para el Desarrollo.
- MEDICINS SANS FRONTIERS, (2004). Energy Guideline
- ACTION CONTRE LA FAIM, (2012). Generator Guideline
- MEDICINS SANS FRONTIERS, (2002). Power Supply.
- ACTION CONTRE LA FAIM. (2012). Energy management Guideline
- SAVE THE CHILDREN. Electricity distribution, generation and renewable energy guide.
- ACTION CONTRE LA FAIM, (2020). Solar pumping, Electrical design and installation.
- INTERNATIONAL COMITEE OF THE RED CROSS and MEDICINS SANS FRONTIERS, (2016). Electrical installation and equipment in the field, Rules and Tools.
- BP, (2000). Solar installation manual
- MEDICINS SANS FRONTIERS, (2012) Electrical safety guidelines
Sites and Resources
- Estimates of sunrays are available from:
- The international database of SolarGis, which offer a lot of free maps, all downloadable at this address: