Why Do My AA Batteries Fail in Devices Despite Testing at 1.5V?

Have you ever faced the perplexing situation where a 24-pack of AA batteries, each supposed to be good until 2028, fails to power any device? Not only that, but when you test them with a multimeter, they register a seemingly healthy voltage of 1.5V. This issue can be frustrating and concerning. In this article, we will explore the possible reasons behind this behavior and provide guidance on how to troubleshoot and resolve the issue.

Understanding Load Testing vs. Open Circuit Voltage

The most common reason for the discrepancy between a battery's open circuit voltage (measured by a multimeter) and its performance in a device is the difference between load testing and open circuit voltage. A multimeter measures the voltage of the battery when it is not under load, which is an open circuit condition. However, devices require the battery to supply current, meaning they operate under a loaded condition. A battery that measures 1.5V under open circuit conditions may not be able to deliver sufficient current under load, leading to poor performance or complete failure in the device.

Shelf Life and Degradation

Even batteries that are not close to their expiry date can degrade over time. Factors such as high storage temperatures, humidity, and improper storage conditions can contribute to this degradation. Over time, this can cause the batteries to lose their ability to deliver the necessary current under a load, resulting in poor device functionality despite the multimeter readings showing the expected voltage.

Exploring Different Battery Types

Not all types of batteries perform equally well under load conditions. Alkaline batteries are particularly prone to this issue. As they get closer to the end of their lifespan, alkaline batteries lose their ability to provide power efficiently, even if the open circuit voltage remains within the expected range. On the other hand, lithium or NiMH batteries may retain their performance for a longer period.

Device Sensitivity and Performance

Sometimes, the device itself can be a factor. Not all devices are equally sensitive to the performance of the battery. If a device requires a higher current than what the battery can deliver, it may cease to function despite the battery showing a healthy voltage when tested with a multimeter. This sensitivity can vary greatly between devices, making it crucial to test the batteries in different devices to rule out any device-specific issues.

Corrosion and Poor Connections

Corrosion on the battery terminals or in the device's battery compartment is another possible cause. Over time, corrosion can build up and disrupt the flow of electricity, resulting in poor performance. Additionally, poor connections within the battery compartment can prevent the device from receiving the necessary power, even if the batteries have a good open circuit voltage.

Manufacturing Defects

In rare cases, there may be a manufacturing defect within the batch of batteries. Although less common, this can lead to a situation where multiple batteries from the same pack fail to function under load. If you encounter consistent issues with a batch of batteries, it might be beneficial to contact the manufacturer for further investigation.

Recommendations for Troubleshooting

To properly troubleshoot the issue, consider the following steps:

Load Testing: Use a battery load tester to evaluate how the batteries perform under actual load conditions. This will help you determine if the batteries are weak or if they are capable of delivering the necessary current. Test in Different Devices: Try testing the batteries in different devices to see if the issue is device-specific. This step can help identify any inherent problems with the batteries themselves. Check Expiration Dates: Ensure that the batteries are not expired and check for any signs of damage or leakage. Damaged batteries can fail to work properly regardless of their open circuit voltage.

By following these recommended steps, you can better understand and resolve the issue with your AA batteries. If the batteries consistently fail under load despite showing proper voltage, it might be best to replace them to ensure reliable performance for your devices.