How to do Current Discharge Experiment with Battery

       How to see the current discharge from the battery? If you use or keep it ideal without using it, current discharge out of battery. In this post, we will see the current discharge from the battery both rechargeable and non-rechargeable batteries. This experiment can use as 5th, 6th and 7th grade science fair projects electricity for students.

      We discussed different types of batteries, you can get more information from our previous post. In main category, Batteries can be classified as a primary and secondary battery. The primary battery is a non-rechargeable battery. Moreover, its workability is totally different from rechargeable or secondary battery.

How to do Current discharge experiment with battery1
Image by achccc from Pixabay

Science Project Idea-1

     The following materials are required to do the experiment for 5th, 6th and 7th grade science fair projects electricity for students.

Materials required for Primary Battery discharge experiment:


  1. Battery 12 V  (primary)   ——    Three pairs
  2. Remote car motor           ——     One 
  3. Multimeter (voltmeter)   ——     One
  4. Stop clock                        ——     One    

About the use of multimeter is discussed in one of our old post. Please go through it before moving any further. 

Standard Operating Protocol for Battery discharge project:

  1. Take one 12 V battery  (primary) check the initial voltage and label as control. The initial voltage of the battery writes down in the notebook.
  2. Another 12 V battery used for the discharge experiment and label it as exp.
  3. Exp battery’s initial voltage noted in the record notebook.
  4. Exp battery is connected with the car motor every 2 min and after that check the voltage of the battery.
  5. Make a table of Time and voltage.
  6. Observe the discharge of voltage with respect to time.

     Once the voltage reaches near-zero or no movement of car motor, you can stop the experiment. At the same time check the voltage of the control battery also. This discharge of the experiment can be repeated three times to get a better average result. It is enough for 5th and 6th grade science fair projects electricity for students. You can present your outcome to school science fair.

    If you are getting exponential decay of the voltage, then you can determine the rate constant for voltage discharge decay. It can be ideally represented in the following

              V = V₀ exp^(- kt)

    Here, V₀ is the initial voltage of the primary battery. k is the rate of voltage discharge of the battery. This rate may fit in one component or multi-component decay. But you can fit all these approximately into one component decay.  t is the time of the observation of voltage. You can use the stop clock to measure time duration. This calculation part has included in 7th grade science fair projects electricity for students. You can present the poster for the science fair. 


How to do Current discharge experiment with battery2
Battery discharge experiment

Science Project Idea-2

     The same battery discharge experiment can be carried out for an advanced way with a secondary battery. It is generally known as a rechargeable battery. The following material is required for a secondary battery discharge experiment.

Material required for secondary battery discharge experiment:

  1.  The rechargeable battery 12 V (secondary)        ——-     Three pairs
  2.  Remote car motor                                                   ——      One  
  3.  Multimeter                                                               ——      One 
  4.  Stop clock                                                                 ——      One 
  5.  Battery charger                                                        ——-     One

Standard Operating Protocol for secondary battery discharge project:

  1. Take the pair of 12 V rechargeable battery and charge it with the battery charger for 1-2 hrs which depends on the battery manufacturer instruction. (read the instruction carefully)
  2. After charging the battery, you take one 12 V rechargeable battery and note down the voltage with a multimeter (voltmeter). It is labeled as a control for the battery discharge experiment.
  3. Another one rechargeable battery used for the entire battery discharge experiment and labeled it as reexp.
  4. reexp’s initial voltage is noted down in the record notebook.
  5. reexp is connected with a remote car motor and note down the voltage every 2 min once.
  6. Make the table of voltage vs time.
  7. Observe the discharge of voltage with respect to time. 
  8. Again recharge the battery for 1-2hrs and repeat step 2 to step 7 name it cycle two.
  9. Totally do five cycles for one battery and repeat the same experiment for the other two pairs.

Observation of discharge of the rechargeable battery:

         Voltage vs time graph gives information on the discharge of the rechargeable battery. From the above said equation, the rate of discharge of rechargeable battery could be calculated. The one advantage is by using the rechargeable battery, you can repeat the experiment in the same battery after charging it. But it is not possible with one time use battery.

        If you are repeating it for five cycles, it gives five rate constant. From this rate constant, easily predict battery life. All pairs of batteries give statistical information. You can compare different voltage battery also. If you use different voltage of the battery, you get different rates of discharge of the battery. You can present this project outcome in 7th grade science fair projects as an electricity experiment.

In this blog, we mainly focus on science fair projects for kids, 3rd, 4th, 5th,6th, 7th,8th and 9th grade students. you can see more project ideas updates in our sitemap

More information on Science Quiz 2020.


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