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What Battery Last Longer?

What Battery Last Longer?

Introduction: (Initial Observation)

Manufacturers of batteries usually advertise and claim that their batteries lasts longer. Not all batteries are the same. They come in different sizes, prices, and chemical compositions. Widely used battery sizes from small to large are AAA, AA, C and D.

Chemical compositions of batteries also vary, but the most widely used are known as alkaline batteries that are not rechargeable.

Why this project is important? How does it help people? What are the benefits of testing batteries?

Testing the battery life is important for makers of batteries so they can verify the quality and maintain the consistency of their products. Each manufacturer has a Quality Control department in charge of testing the products and reporting the results. Engineers can use such results to identify flaw in their production and improve the quality of their products. Without such tests, the producers will not know if their products are usable for the buyers or not and they may experience many returns of their defective products.

Testing batteries is also important for large buyers such as toy manufacturers or makers of battery operated electronic devices. If they use low quality batteries in their products, they will loose their reputation and loose customers because consumers will see a failed electronic product, not a failed battery. For example if you buy a computer that stop working after 3 months, you think of it as a bad computer, even though the failure may be just due to a low quality battery.

Battery life is also important for aviation industry. If the battery fails in a satellite or in an airplane, it can have expensive and tragic outcomes.

By testing the batteries and being aware of their life expectancy, we can prevent many problems and will know if we are getting them at the right price.

This project guide contains information that you need in order to start your project. If you have any questions or need more support about this project, click on the “Ask Question” button on the top of this page to send me a message.

If you are new in doing science project, click on “How to Start” in the main page. There you will find helpful links that describe different types of science projects, scientific method, variables, hypothesis, graph, abstract and all other general basics that you need to know.

Project advisor

Information Gathering:

Find out about battery and how it works. Read books, magazines or ask professionals who might know in order to learn about the factors that may affect a battery life. Keep track of where you got your information from.

A battery (also called a cell) is essentially a can full of chemicals that produce electrons. Chemical reactions that produce electrons are called electro-chemical reactions.
If you look at any battery, you’ll notice that it has two terminals. One terminal is marked (+), or positive, while the other is marked (-), or negative. In an AA, C or D cell (normal flashlight batteries), the ends of the battery are the terminals. In a large car battery, there are two heavy lead posts that act as the terminals.

Electrons collect on the negative terminal of the battery. If you connect a wire between the negative and positive terminals, the electrons will flow from the negative to the positive terminal as fast as they can (and wear out the battery very quickly — this also tends to be dangerous, especially with large batteries, so it is not something you want to be doing). Normally, you connect some type of load to the battery using the wire. The load might be something like a light bulb, a motor or an electronic circuit like a radio.

In order for a battery to last longer, it needs to have a better chemical composition or better ingredients. We can test and compare batteries to see which one last longest.

Batteries that are larger in size, have more active chemicals, so they will last longer than smaller size batteries. For example a D cell battery will last more than a C cell battery and C cell will last longer than AA battery in equal conditions. Equal conditions means the same brand, the same chemical composition and the same electrical load.

For the purpose of this project we will test only AA size alkaline batteries with each other to see which battery last longest.

Question/ Purpose:

What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
Which brand AA size alkaline battery lasts longer? Does the cost of battery has anything to do with its durability?

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.
The most important variable that affect the life of a battery is the load. Load is what consumes the battery. For example in a flashlight, the light bulb is the load. But not all light bulbs are the same. Some consume more electricity than others. Since we intend to compare batteries, the only thing that we need to be sure about, is that we use the same load (for example the same type light bulb) for all tests.

For our experiment, the brand of battery is the independent (or manipulated) variable. The life of battery in hours is the dependent (or responding) variable.

Constants are the load, the size of battery.

Controlled variables are room temperature and experiment procedures/ method. In other words you can’t test one battery in a hot room and the other one in a cold room.

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Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.
I think more expensive batteries last longer.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Experiment 1: Testing battery life using a light bulb or flashlight

Get four small identical flashlights that use only one AA size battery and number them from 1 to 4.

Gather four AA size batteries, from four different brands (one of each brand)

Place the batteries in the flashlights.

Place all four flash lights on the edges of a table, in a dark room, faced to the wall, in a way that the flashlights are about one foot apart and about one foot away from the wall. In this way you can also see if all batteries produce the same light.

Turn on all four flash lights and make frequent observations and record the results in a table similar to the following:

 Battery #1 Battery #2 Battery #3 Battery #4
 8:00  100 80 90 100
 8:15  100  90 90  100

The above table in your experiment will have about 30 lines if you inspect the lights every 15 minutes. In the left column we have inspection times. As you see we started our test at 8 o’clock in the morning and inspected and recorder the lights every 15 minutes. At the top row we have titles such as battery #1 and battery #2, but we could also use the actual brand names instead; such as SONY, Energizer, and etc.

At each observation, we give a grade to each light. The brightest one always gets 100 and the others get the same or lower grades depending on their brightness.

We continue observation and recording every 15 minutes until all batteries lose power and all lights are completely off. The one that is off gets 0 as it’s grade while others still get numbers equal to 100 or less.

You will use this table to analyze your results and answer questions.

Experiment 2: Testing battery life using an electromagnet


In the previous method you had to visually detect the loss of power in the battery by looking at the light bulb filament. In this new method you use the battery to build an electromagnet. The electromagnet will be strong enough to hold a nail or a paper clip. When the battery weaken, the nail or paper clip will fall. In this way you can be doing your other works and record the time when you hear the sound of dropping nail or paper clip.

Variables: In this experiment the battery is the manipulated variable. The magnet holding time (or battery life) is the responding variable.



This experiment is based on a science kit from MiniScience.com; however, you don’t have to buy a kit. All material needed for this experiment may be obtain locally or substituted with things that can be found at home. Here is the list of material:

  1. Wooden base
  2. Wooden cross for holding electromagnet
  3. 2″ or 3″ common nail
  4. Battery holder
  5. 4 feet magnet wire gauge 23 (or any other solid insulated wire, gage from 23 to 30).
  6. Metal weight such as another nail, bolt or nut.
  7. Other material and tools such as wood glue, tape, drill, sandpaper, …

Material Notes:

  • Magnet wire is insulated wire. Insulation in magnet wire is like some kind of paint. You need to remove the insulation from the ends of wire, where it connects to the battery or battery holder. Insulation of magnet wire can be removed using a sandpaper.
  • You can not use bare copper wire to make an electromagnet.


Construct a wooden cross and secure it on a wooden base. We use wood for this structure because wood is not conductive and is easy to glue.

Insert a nail in one end of the upper bar. (If you are using a kit, your wood dowel may already have a hole for this).

Get a 4-feet piece of insulated wire. Leave one foot from one end and then start to wrap the wire around the nail. Wrap only two feet of wire, so at the end you will have another foot of wire remaining.

Remove the insulation from the ends of wire and connect them to the battery holder. (Make sure there are no batteries in battery holder at this time)

Battery holders included in a kit have a simple mechanism for connecting the wire. If you are using a different battery holder or no battery holder at all, you must make sure the a secure connection exists between your wires and the battery.

Place the battery in the battery holder and hang a nail or any other metal object to your electromagnet. Record the time and wait until the metal object falls. Record the fall time.

Remove the battery and leave it out for one hour and then repeat the test again. This time the metal object falls in a shorter time.

Subtract the start time from drop time to calculate the battery life in your first and second experiments.

Record the results in a table like this:

Battery Life
First try
 Battery Life
Second Try
 Battery 1  xxx minutes
 Battery 2
 Battery 3


Make a graph:


You can make a bar graph to visually present your results. Draw one vertical bar for each brand battery you have tested. Write the name of each bran bellow or over the bar it represents. The height of each bar must show the life of one specific brand. (For example a bar that is 17cm tall may indicate 17 hours of battery life)

Materials and Equipment:


For this experiment you will use a flash light or build a basic electric circuit to test the life of a battery. As you see in the following picture, a light bulb and a battery are mounted on a board in the form of a basic electric circuit. Such a setup can also be used for battery test. If you don’t have 4 set of test circuits or four identical flashlights, you can repeat the test four times, once for each battery. But we don’t recommend that because you will not be able to compare the brightness of the bulbs. Brightness is important because some batteries may produce electricity slower than others, so they will last longer. Slow production of electricity means some devices such as a walkman player, will never get enough energy for a good performance.

Basic electric circuit


To get a better idea about battery life, think about 2 bottles of water, one smaller with a narrow neck and the other larger with a wide moth. If both bottles are full of water and you try to empty them, the bottle that is smaller and has less water may take more time to get empty, because that bottle has a narrow neck. So lasting longer can be the result of a slow discharge, not more energy.

A list of material is as follows:

  1. Four small flashlights that take one AA battery each or four basic electric circuits
  2. Four new AA size batteries of four different brands
  3. Papers and pen to record your results.
  4. Clock or watch to record time

Results of Experiment (Observation):

Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.


You can describe the battery life based on the number of minutes that it last for a certain task and use the same numbers for comparison. So no calculation will be required.
If you are doing experiment number 2, you may add the battery life in your first try and second try and write the total (in a new column) as the total battery life.

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.

It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.


Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

Try to answer the following questions using your recorder data.

  • Which battery lost it’s energy faster?
  • Which battery last longest?
  • How many hours was the life of the battery that last longest?
  • How many hours was the life of the battery that last shortest?
  • Which battery had the most light during your observation?
  • Did the cost of battery have any relation with it’s life?
  • What did you learn from your experiment?
  • Did you learn any thing new from your project?
  • What was the most interesting part of your project?

Please send a copy of your data for your project advisor to info@ScienceProject.com

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.


I researched on how a battery produces electricity. The battery is a dry cell. A chemical reaction between the electrolyte and the zinc electrode helps produce electricity.


  • Electrodes – The negative or positive part of an electric cell.
  • Electrolyte – A liquid or moist substance that conducts electricity.
  • Dry Cell – An electrical cell that has a moist electrolyte.
  • Terminal – The negative or positive end of an electrolyte.