There are several applications of solar energy which do not need to store energy but for run time operation of device throughout the day(refrigerator in home, mini floor mill, small workshop tools and many other devices who can be made operating with DC supply ).

Current solar systems are generally used for night lightning load by charging battery all day. Solar systems are underestimated for many day time applications. Also if used, unnecessary application of battery is going on for small duty cycle loads. Also for loads which require high currents can’t be delivered directly by solar panel or batteries.

Now a day, super capacitor is being used in the great applications as supporting device to the main battery supply. In our application, super capacitor will act as supporting device to the solar panel or to the battery. It can also be used in between battery and solar panel to fast charging and discharging.


Ultra capacitor is suitable for this application because of following some properties:


1] High power density than the battery that it can rapidly charge/discharge efficiently.

2] It can be used for more charging and discharging cycles than batteries.

3] It draws maximum current while charging and the current simply stops flowing when completely charged. Hence, it does not subject to the overcharge and not require overcharge protection.

4] Short duration power boost.

5] High capacitance than normal electrolytic capacitor.

6] Constant current discharge to load.

7] Exceptional life cycle.


1] Linear voltage discharge to load hence can’t used as storage device alone but requires in addition the dc-dc converter which increases cost and introduces power noise in the circuit.

2] Maximum voltage rating available is only 2.7v.

3] Series connection is required for higher voltage rating which results into

  1. a) Reducing the equivalent capacitance.
  2. b) Increase in cost.
  3. c) Requires extra balancing circuit.

Experiment on available super capacitor:


  • About charge controller, solar cells, electrolytic capacitor etc.
  • Constraints for the application of super capacitor.
  • Voltage and Current behaviors in any electrical circuit.
  • Current research trends in super capacitor technology.
  • Design of circuits by integrating different electronic devices.
  • Buck converter, Boost converter, Buck-Boost converter.
  • Comparison between battery, electrolytic capacitor and super capacitor.
  • Balancing of super capacitor cells.
  • Selection of super capacitor for given constant power or constant current application.

Current stage/conclusion:

Super capacitor can be effectively used in the following applications,

  • Supply for Projects in our campus who are of short duty cycles.
  • To supply load which can’t be driven by solar cell with battery or alone solar cell.
  • To charge the battery at faster rates.


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