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How to Tell if a LiPo Battery is Bad


LiPo batteries, short for Lithium Polymer batteries, have become increasingly popular due to their high energy density, lightweight design, and ability to provide consistent power output. These rechargeable batteries are commonly used in a wide range of devices, including drones, RC cars, laptops, and portable electronics.

While LiPo batteries offer numerous advantages, it is crucial to understand how to determine if they are in good condition or if they have deteriorated over time. Recognizing the signs of a bad LiPo battery is not only essential for extending its lifespan but also for ensuring safety during usage.

Identifying a bad LiPo battery is crucial because it can help prevent potential hazards such as fires, explosions, or damage to your devices. Additionally, a degraded battery can significantly impact the performance of your devices, leading to shorter runtimes, reduced power output, and overall decreased efficiency.

By being aware of the signs that indicate a bad LiPo battery, users can take necessary precautions, avoid potential accidents, and maintain the longevity and optimal performance of their LiPo batteries.

In the following sections, we will discuss the various indicators that suggest a LiPo battery may be in poor condition. By carefully examining these signs, you can make an informed decision about whether it’s time to replace your LiPo battery or take appropriate action to ensure its safe and efficient use.

Visual Inspection

Visually inspecting your LiPo battery is the first step in determining its condition. This simple yet crucial process can provide valuable insights into the overall health of the battery. Significance of Visual Inspection: A visual inspection allows you to identify any visible signs of damage or abnormalities in the battery. It serves as an initial indicator of potential issues and helps you make an informed decision about the battery’s usability and safety. Here are some key points to consider during a visual inspection:


Check if the battery appears swollen or puffed up. A bloated LiPo battery indicates a buildup of gas inside, which can be a result of internal chemical reactions or overcharging. A swollen battery should never be used, as it could potentially rupture or catch fire. Dents

Look for any noticeable dents on the battery casing. Dents may suggest that the battery has been subjected to physical impact or mishandling, which can compromise its structural integrity and overall performance.


Examine the battery surface for punctures or holes. If the battery has been pierced, either accidentally or intentionally, it can lead to electrolyte leakage or thermal runaway. Such a battery should not be used under any circumstances.


Check for any signs of fluid leaking from the battery. Leaking electrolyte, typically seen as a sticky or greasy substance, indicates a damaged cell within the battery pack. A leaking LiPo battery is both unsafe and ineffective.

If you observe any of the aforementioned signs of physical damage, it is essential to treat them as warning signs. Using a LiPo battery with visible damage can pose severe risks, including fire hazards and potential damage to connected devices. In such cases, it is best to dispose of the battery in accordance with local regulations and replace it with a new, undamaged one.

Remember, visual inspection should be performed regularly, especially before and after each use of the LiPo battery. It is a simple yet effective way to identify obvious issues and ensure the safety and reliability of your LiPo battery during operation.

Voltage Testing

To assess the condition of a LiPo battery, voltage testing is a crucial step. By measuring the battery’s voltage, you can evaluate its charge level and identify any potential issues with individual cells. Here’s what you need to know about voltage testing:

Measuring Voltage–Using a LiPo voltage checker

These compact devices are specifically designed to measure the voltage of LiPo batteries accurately. Simply connect the balance lead of your LiPo battery to the voltage checker, and it will display the voltage readings of each cell.

Measuring Voltage–Using a multimeter

If you don’t have a LiPo voltage checker, a multimeter can be used as an alternative. Set the multimeter to the DC voltage measurement setting, and carefully touch the positive (red) and negative (black) probes to the corresponding balance lead pins. Ensure the correct polarity while making the connections.

Nominal Voltage Rating

LiPo batteries typically have a nominal voltage rating of 3.7 volts per cell. This means that a healthy single-cell LiPo battery should ideally show a voltage reading close to 3.7 volts during normal operation. For example, a fully charged 3-cell LiPo battery should read approximately 11.1 volts (3.7V x 3 cells).

Significantly Lower Voltage Reading

If you find that the voltage reading of one or more cells is significantly lower than the nominal voltage rating, it may indicate a bad cell within the battery pack. A cell with a notably lower voltage can suggest an imbalance or damage within that specific cell, affecting the overall performance and capacity of the battery.

If you suspect a bad cell, it is advisable to discontinue using the battery immediately. A LiPo battery with imbalanced or damaged cells can become unstable, leading to potential safety hazards. It is recommended to replace the battery or consult a professional service for further assessment and potential repair.

Remember, voltage testing is an essential part of battery maintenance and can help identify potential issues before they escalate. Regular voltage checks will allow you to monitor the health of your LiPo battery and ensure its optimal functioning and longevity.

Balancing Checks

LiPo batteries feature balance leads, which consist of multiple wires connected to each cell in the battery pack. These balance leads enable the measurement of voltage in each cell independently. Monitoring and maintaining balanced cell voltages promote efficient energy distribution, prevent overcharging or discharging of individual cells, and enhance the overall safety and longevity of the battery.  Ensuring the cells within a LiPo battery are balanced is crucial for maintaining optimal performance and extending the battery’s lifespan. Balance leads, present in LiPo batteries, allow for individual voltage monitoring of each cell. Here’s what you need to know about balancing checks:

Using a LiPo Balancer or Charger with Balancing Capabilities

LiPo Balancer

A LiPo balancer is a device specifically designed to equalize the voltage across all cells of a LiPo battery. Connect the balance lead of the LiPo battery to the balancer, and it will discharge the higher voltage cells while monitoring and adjusting the charge levels until all cells are balanced.

Charger with Balancing Capabilities

Many LiPo chargers come equipped with built-in balancing functions. When charging a LiPo battery with such a charger, connect the main power lead and the balance lead to the charger. The charger will automatically monitor and balance the individual cell voltages during the charging process.

Identifying Significant Voltage Differences

During the balancing process, it is essential to check for significant voltage differences between cells. Ideally, the voltage readings of each cell should be as close to each other as possible. If there is a significant voltage difference between cells (usually exceeding a few millivolts), it may indicate a faulty cell within the battery pack.

A significant voltage difference could result from various factors such as cell damage, aging, or imbalanced charging or discharging. If you observe a notable voltage discrepancy, it is advisable to discontinue using the battery and seek professional assistance or replace the battery to ensure safe and reliable operation.

Performance Evaluation

Testing the performance of a LiPo battery in the device or equipment it powers is essential for identifying any signs of poor performance or degradation. Here’s what you need to know about evaluating battery performance:

Testing in the Relevant Device

To evaluate the battery’s performance, test it in the specific device or equipment it powers. Follow these steps:

  • Make sure the battery is fully charged before testing.
  • Install the battery in the device according to the manufacturer’s instructions.
  • Run the device under typical operating conditions, such as normal usage or workload, for a specific period.

Indicators of Poor Performance

While testing the LiPo battery’s performance, be aware of the following indicators that may suggest poor performance:

  • Diminished Run-time: If you notice that the battery’s runtime has significantly decreased compared to its previous performance, it could indicate diminished capacity or aging of the cells.
  • Reduced Power Output: If the device or equipment exhibits lower power output or struggles to maintain its performance level, it may suggest that the battery cannot deliver sufficient power to meet the demands.
  • Inability to Hold a Charge: If the battery loses charge quickly, even when not in use, or fails to hold a charge at all, it indicates a significant decrease in its capacity and overall health.

Consistent Underperformance and Battery Replacement

If you consistently observe poor performance indicators even after fully charging the battery, it is likely time to consider battery replacement. LiPo batteries have a limited lifespan, and over time, they naturally degrade and lose their effectiveness. If the battery no longer meets the requirements of the device or fails to provide reliable power, it is advisable to replace it.

Regular evaluation of battery performance, especially through monitoring run-time, power output, and charging behavior, can help you identify when a LiPo battery is no longer performing optimally. By recognizing signs of poor performance, you can ensure the uninterrupted operation of your devices and maintain their efficiency.


In conclusion, monitoring and evaluating the performance of a LiPo battery is crucial for identifying signs of deterioration or poor performance. By testing the battery in the relevant device or equipment it powers and being aware of indicators such as diminished run-time, reduced power output, and the inability to hold a charge, you can determine if a LiPo battery is bad.

Consistent underperformance serves as a clear indication that the battery may need to be replaced. LiPo batteries have a limited lifespan, and over time, they naturally degrade, resulting in decreased capacity and performance.

Regularly assessing the battery’s performance helps ensure the reliable operation of devices and equipment. If you notice significant signs of poor performance, it’s recommended to seek professional assistance or replace the battery to maintain optimal functionality and prevent potential hazards associated with a bad LiPo battery.

Remember, staying vigilant and proactive in evaluating the condition of your LiPo battery will contribute to the longevity and safety of your devices while maximizing their performance.

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