I did a science experiment on batteries. I ran five brands of AA Alkaline batteries until they would no longer run a small light bulb. I measured the voltage of each battery every hour.
I did this experiment four times using the same type of light bulb and the same brand of batteries from the same four pack of batteries.
The same brand of batteries acted differently during each run.
Sometimes the would spike when they should have dropped. Sometimes they ran significantly longer than there usual pattern.
Why do AA batteries run so differently from each other? Most cost a similar amount of money. All had the same use by date. Why does one battery last six hours and another last 10. Aren't they made of the same chemicals?
There are several factors that can contribute to the variation in performance among AA batteries, even if they are from the same brand and have the same use by date. Here are some possible reasons:
1. Quality control: Despite being manufactured by the same brand, there can still be variations in quality control processes. This means that some batteries may have been produced with better consistency and higher quality materials, while others may have slight variations or defects.
2. Manufacturing differences: Even though batteries may appear the same on the outside, there can still be variations in the manufacturing processes. This can lead to slight differences in the internal components, construction, or chemical makeup of the batteries, which can affect their performance.
3. Chemical composition: While AA batteries are generally made of similar chemical compositions, there can still be variations in the specific formulation and the purity of the materials used. These differences can impact the overall energy capacity and discharge characteristics of the batteries.
4. Storage conditions: Even if all batteries have the same use by date, they may have been stored in different conditions before reaching the consumer. Factors such as temperature, humidity, and exposure to extreme conditions can affect the overall performance and shelf life of batteries.
5. Usage patterns: The performance of batteries can also be influenced by the specific application they are used in. Some devices may require higher currents or have different voltage requirements, which can affect how quickly the battery drains and its overall runtime.
It's important to note that variations in performance are not uncommon for consumer batteries, and they can occur even within a single brand or batch. Additionally, the performance characteristics of batteries can change over time, especially as they age or are exposed to different usage conditions.
The variation in performance among different brands of AA batteries can be attributed to several factors. While the chemistry inside the batteries is generally the same, there are other factors that can impact their performance. Here are a few possible reasons for the differences you observed:
1. Quality control: The manufacturing process for batteries can vary between brands, and some brands may have better quality control measures in place than others. This can result in variations in the consistency of the chemicals and materials used inside the batteries, which can affect their performance.
2. Construction and design: The design and construction of batteries can vary between brands. Factors such as the composition and thickness of the electrodes, the quality of the electrolyte, and the overall assembly of the battery can influence its performance. Some brands may invest more in research and development to improve battery design, leading to better performance.
3. Internal resistance: Batteries have internal resistance due to the materials used and the structure of the battery. This resistance can vary between different brands, affecting how efficiently the battery can deliver its power to the electrical load (in this case, the light bulb). Batteries with lower internal resistance will generally perform better.
4. Capacity and energy density: While batteries may have the same nominal voltage (e.g., 1.5V for AA alkaline batteries), their actual capacity and energy density can vary. Capacity refers to the amount of charge a battery can store, while energy density refers to the amount of energy a battery can store per unit volume or weight. Batteries with higher capacity and energy density will typically last longer.
5. Shelf life and storage conditions: Even though the batteries you used had the same use-by date, their shelf life and storage conditions prior to purchase could have varied. Batteries deteriorate over time, and if they were stored in unfavorable conditions such as high temperature, humidity, or exposure to extreme cold, their performance may be negatively affected.
It's worth noting that variations in performance can also occur within the same brand and even within the same pack of batteries. This is due to the natural variation during the manufacturing process and the potential for inconsistencies in quality control.
To better understand the specific performance characteristics of different batteries, it is recommended to refer to technical specifications provided by the manufacturers or conduct more controlled experiments with a larger sample size.