Solar Charging System Basic Principles and Design


With the development of the Internet of Things, many smart electronic devices are moving towards low power consumption.


Different natural energy sources such as solar energy, wind energy, and mechanical energy can be utilized as power sources for electronic devices.


Next, I’ll share with you the operational principles of a solar charging circuit.


Introduction to Solar Charging Circuit


The solar systems provided by HIGHFLY are suitable for common household appliances and lighting, such as adjusting the brightness of daylight lamps and running refrigerators.


It can meet the requirements for the normal operation of the entire household!


I’ll try to express the effects in simple language. If you still don’t understand, you can click [here] to leave your questions and contact information. Our experts will contact you within two working days!
Basic Principles and Prototype of the Circuit


The overall circuit prototype is:


Sunlight (energy source) – Energy storage device – Load


In the above circuit, two essential components are needed: a supercapacitor and a solar panel.


The solar panel is the source of energy in the circuit prototype, while the supercapacitor serves as the energy storage device.


What is a Supercapacitor?


(from wikipedia)


Why Use Supercapacitors Instead of Batteries?


In simple terms, it boils down to the usage scenarios and characteristics of supercapacitors.


* The charge-discharge circuit of supercapacitors is simpler compared to batteries.


* Compact Size for IoT Devices.


* Supercapacitors have a small footprint, making them suitable for small, low-power IoT products.


* High Energy Conversion Efficiency and Low Self-Discharge.


* Supercapacitors exhibit high energy conversion efficiency, and they have minimal self-discharge.


* Unlike batteries, overcharging and overdischarging do not have a negative impact on the lifespan of supercapacitors.


Pictures of supercapacitors


There are all kinds of supercapacitors, and the one I used in our recommended circuit today looks like the following: 


Note that the higher capacity of the supercapacitor does not only mean a longer charging time;


It also means that the whole circuit takes longer to “start”;


Because of the large capacity, the start-up time to reach the voltage at which the load can operate normally is longer!


Solar Panels



When selecting solar panels, setting aside structural considerations and focusing on electrical parameters, the key aspects to consider are voltage and current.


Among these, the current significantly affects the charging speed and can reflect the manufacturing quality of the solar panel. Although the charging speed is an essential indicator of the product, it might not be the primary focus of our discussion.


Solar panels have two voltage specifications: open-circuit voltage and operating voltage.


Open-Circuit Voltage (Voc):

This is the theoretical maximum voltage that the supercapacitor can be charged to. It provides an understanding of the upper limit of the charging potential.
Operating Voltage:

This represents the maximum voltage the solar panel can output when connected to a load.


However, the accuracy of this point depends on the actual load and usage conditions. Manufacturers typically specify it based on a standardized load in a specific testing environment, making it somewhat less accurate for real-world applications.
Considering the specifications of the supercapacitor mentioned earlier, such as a 3.6V rating, you would need a solar panel with an open-circuit voltage greater than 3.6V to ensure the supercapacitor can reach its full charge.


However, it’s worth noting that the supercapacitor can still be used even if not fully charged.


The choice depends on your specific usage scenario.





The above constitutes the working principles of a solar energy system.


It might seem intricate at first glance, but rest assured that we can provide you with professional services and high-quality products, backed by comprehensive after-sales support!


No need to worry!




We offer customized services that support OEM or ODM, We can customize the product with your company’s logo and also provide customization of the product’s size and wattage.



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