Batteries are essential for powering many of our devices, but sometimes a single battery isn’t enough. To get the power we need, we often connect multiple batteries together. There are two main ways to connect batteries: in series and in parallel. Let’s explore what these terms mean and how they affect the power we get from the batteries.
When we connect batteries in series, we add up the voltage of each battery. For example, if you have two 1.5-volt batteries connected in series, you’ll get a total of 3 volts. Adding a third battery would give you 4.5 volts. This happens because each battery boosts the electrons, increasing the overall voltage. However, the capacity, which is how long the battery can last, stays the same as a single battery.
Connecting batteries in parallel is different. No matter how many 1.5-volt batteries you connect in parallel, the voltage remains 1.5 volts. However, the capacity increases, meaning the batteries can power a device for a longer time. For instance, if one battery has a capacity of 1,200 milliamp hours (mAh), two batteries in parallel would have a capacity of 2,400 mAh. This setup is useful when you need a longer-lasting power source but not a higher voltage.
The capacity of a battery is measured in milliamp hours (mAh). This tells us how long a battery can provide a certain amount of current. For example, a 2,500 mAh battery can theoretically supply 2,500 milliamps for one hour or 1,250 milliamps for two hours. However, in real life, factors like the battery’s age, temperature, and internal resistance can affect how long it actually lasts.
To estimate how long a battery will last, you can use this formula: Battery Life = Capacity (mAh) / Circuit Current (mA). For example, if a circuit uses 19 milliamps and the battery has a capacity of 3,000 mAh, the estimated battery life would be about 157.9 hours. Keep in mind that this is an ideal estimate, and actual performance may vary.
To measure a battery’s voltage, use a multimeter set to the DC function. Connect the red lead to the positive terminal and the black lead to the negative terminal. This will give you a voltage reading. A 1.5-volt battery might read slightly higher, like 1.593 volts, when it’s new. As the battery discharges, the voltage will drop. A dead battery might read around 1.07 volts.
To fully test a battery, it’s important to check it under load conditions. This means connecting a resistor, such as a 100-ohm resistor, between the multimeter probes. When the battery is under load, the voltage should only drop slightly if the battery is still good. For example, a battery might read 1.593 volts with no load and 1.547 volts under load. If the voltage drops significantly, like to 0.863 volts, the battery is likely out of charge.
That’s all for now! Keep exploring and learning about electronics, and don’t forget to check out more resources and videos to expand your knowledge.
Gather some AA batteries, wires, and a small light bulb. Try connecting two batteries in series and observe the brightness of the bulb. Then, connect the same batteries in parallel and note any changes. Discuss why the brightness changes based on the type of connection.
Using the information from the article, calculate the total voltage and capacity for different combinations of batteries. For example, calculate the voltage and capacity for three 1.5-volt batteries connected in series and in parallel. Share your findings with the class.
Choose a device you use daily and research its power consumption in milliamps. Using the formula provided in the article, estimate how long a 3,000 mAh battery would last in that device. Present your estimation and discuss factors that might affect the actual battery life.
Practice using a multimeter to measure the voltage of different batteries. Record the voltage of new and used batteries and compare the readings. Discuss how the voltage readings relate to the battery’s charge level.
Perform a load test on a battery using a multimeter and a resistor. Record the voltage with and without the load. Analyze the results to determine the battery’s condition and discuss why load testing is important.
Here’s a sanitized version of the provided YouTube transcript:
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We can use a battery to power some components, but usually, a single battery isn’t enough to power our devices. For this, we need to combine the batteries. We can connect batteries in two different ways: series or parallel. We have covered these circuit types in great detail previously, so do check those out; links can be found in the video description below.
When we connect the batteries in series, the voltage of each battery is added together. For example, two 1.5-volt batteries give us three volts, and three batteries give us 4.5 volts. The actual voltage might be slightly different in the real world. The voltage increases because each battery boosts the electrons that enter it, resulting in a higher voltage.
If we connect the batteries in parallel, we only get 1.5 volts regardless of how many we connect together. This is because the path merges at the supplier but splits at the return, so the electrons will not be boosted. However, this configuration will provide more current and have a larger capacity, allowing us to power something for longer. For instance, if a battery has a capacity of 1,200 milliamp hours and we place two in parallel, we will have a capacity of 2,400 milliamp hours but a voltage of only 1.5 volts. If we wire them in series, we now have a capacity of just 1,200 milliamp hours but a voltage of 3 volts.
We use batteries to power our circuits, but how long can a battery power our circuit? When we look at the packaging or datasheet for a battery, we see a value with the letters mAh next to it. This is the milliamp hour rating. For example, a battery with a rating of 2,500 milliamp hours could theoretically provide a current of 2,500 milliamps for one hour, or 1,250 milliamps for two hours, or 20 milliamps for 125 hours. However, in real life, it probably won’t last this long because the chemical reaction slows down, and the internal resistance of the battery changes as it empties. Other factors, such as age and temperature, also affect this. There’s no precise way to calculate the lifespan; the best method is to test it.
We can estimate the lifespan using the following formula: battery life equals the capacity in milliamp hours divided by the circuit current in milliamps. For example, if a circuit demands 19 milliamps and the battery has a capacity of 3,000 milliamp hours, then 3,000 divided by 19 gives us approximately 157.9 hours. However, this is the best-case scenario, and in reality, it almost certainly won’t achieve this. We have also built a free, simple calculator on our website where you can estimate the runtime of a battery as well as the required capacity; links can be found in the video description below.
To measure the voltage, we simply need to select the DC function on our multimeter and connect the red lead to the positive terminal and the black lead to the negative terminal. This will give us a voltage reading. For example, a battery rated at 1.5 volts might read 1.593 volts when tested. The two values are close but usually not the same. When the battery is dead or dying, we get a lower voltage. For instance, a battery might read 1.07 volts when it’s completely dead. However, sometimes we could still get a voltage of around 1.5 volts even if the battery is no longer useful.
To fully test the battery, we need to check it under load conditions, which requires a resistor. We can use a resistor of around 100 ohms, but it doesn’t have to be exactly this value. We connect the resistor between our two probes; in this case, I’ve used some clips to connect the resistor. This way, current will flow through the resistor, and we can take a voltage reading as this occurs. If the battery is still good, the voltage level will only drop slightly. For example, a battery rated at 1.5 volts might read 1.593 volts with no load, and when the resistor is connected, it might read 1.547 volts, indicating that the battery is still good.
However, another battery rated at 1.5 volts might read exactly 1.5 volts with no load, but when we connect the resistor, the voltage drops to 0.863 volts, indicating that this battery has run out of charge.
That’s it for this video! To continue your learning, check out one of the videos on screen now, and I’ll catch you in the next lesson. Don’t forget to follow us on social media and visit engineeringmindset.com.
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This version removes any informal language and maintains a professional tone while preserving the essential information.
Batteries – Devices that store chemical energy and convert it into electrical energy to provide power to electronic devices. – Example sentence: The remote-controlled car uses batteries to power its motor and lights.
Voltage – The electric potential difference between two points, which causes current to flow in a circuit. – Example sentence: The voltage of a standard household outlet is typically 120 volts in the United States.
Capacity – The amount of electric charge a battery can store, usually measured in ampere-hours (Ah). – Example sentence: The smartphone’s battery has a capacity of 3000 milliamp-hours, allowing it to last all day on a single charge.
Series – A circuit configuration where components are connected end-to-end so that the same current flows through each component. – Example sentence: When batteries are connected in series, their voltages add up, providing more power to the device.
Parallel – A circuit configuration where components are connected across common points, allowing multiple paths for current to flow. – Example sentence: In a parallel circuit, if one light bulb burns out, the others will continue to shine.
Current – The flow of electric charge through a conductor, typically measured in amperes (A). – Example sentence: The current flowing through the circuit was measured at 2 amperes.
Milliamp – A unit of electric current equal to one-thousandth of an ampere. – Example sentence: The LED light draws only 20 milliamps of current, making it very energy-efficient.
Measure – To determine the size, amount, or degree of something using an instrument or device. – Example sentence: We used a multimeter to measure the voltage across the resistor in the circuit.
Resistor – An electrical component that limits or regulates the flow of electrical current in a circuit. – Example sentence: Adding a resistor to the circuit helped reduce the current to a safe level for the LED.
Load – An electrical component or portion of a circuit that consumes electric power. – Example sentence: The motor acts as a load in the circuit, converting electrical energy into mechanical energy.
