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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 .

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Charge Method

3 stage


Battery Charge

Multi-Stage MPPT

Conversion Rate

Turn solar to electricity



Ampere Rate

30A -100A



small solar system

Product Range


Large power system


Average price

  • PWM Regulators have a longer and proven history.
  • PWM Regulators are a more simple structure and are more cost-effective.
  • Easily deployed.
  • Maximum power point tracking algorithm increases power conversion rate up to 99%.
  • 4 stage charging is better for batteries.
  • Scalable for large off-grid power system.
  • Available for solar systems up to 100 Amps.
  • Available for solar input up to 200V.
  • Offer flexibility when system growth required.
  • Equipped with multiple protection devices.
  • Low conversion rate.
  • Input voltage must match battery bank voltage.
  • Less scalability for system growth.
  • Lower output.
  • Less protection.
  • High cost, usually twice a PWN.
  • Larger Size than a PWM regulator.


  • 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. 


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  • ACTION CONTRE LA FAIM. (2012). Energy management Guideline
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  • 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.
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  • MEDICINS SANS FRONTIERS, (2012) Electrical safety guidelines

Sites and Resources