Battery Management System Malfunction (Here Is What To Do)

Battery Management System Malfunction

‍Have you ever wondered how to fix a battery management system malfunction? Well, we got you covered.

A Battery Management System (BMS) is a crucial component in electric vehicles and other devices that rely on rechargeable batteries. It is responsible for monitoring and managing the battery’s state of health, ensuring optimal performance and longevity.

However, like any other electronic system, a BMS can malfunction due to various factors. In this comprehensive guide, we will discuss the causes, symptoms, and possible solutions to Battery Management System malfunctions while providing an in-depth understanding of this essential system.

What is a Battery Management System (BMS)?

A Battery Management System is an electronic system designed to monitor and control the charging and discharging of a battery pack, ensuring the battery operates within safe limits.

The primary function of a BMS is to maintain the battery’s health by monitoring parameters such as voltage, current, and temperature. Additionally, a BMS may include features like cell balancing, protection against overcharging and over-discharging, and state-of-charge estimation.

Importance of BMS in Electric Vehicles

In electric vehicles (EVs), the BMS plays a vital role in managing the battery pack, which powers the entire vehicle. A well-functioning BMS ensures optimal battery performance, maximizing the vehicle’s driving range, and extending the overall battery life.

A malfunctioning BMS, on the other hand, can lead to reduced driving range, longer charging times, and even potential safety risks.

Common Causes of BMS Malfunctions

There are multiple factors that can contribute to a BMS malfunction. Some of the most common causes include:

Hardware Failures

Hardware failures in the BMS can result from manufacturing defects or damage sustained during use. These failures can lead to inaccurate monitoring of the battery’s parameters, causing the BMS to make incorrect decisions about charging and discharging.

Firmware Bugs

Firmware bugs can occur in the BMS software, leading to incorrect operation or even complete system failure. These bugs can be introduced during the software development process or due to software updates.

Inadequate Calibration

The BMS requires accurate calibration to monitor and manage the battery pack effectively. Inadequate calibration can lead to incorrect readings of the battery’s state of charge and state of health, causing the BMS to make inappropriate decisions regarding charging and discharging.

Environmental Factors

Environmental factors, such as extreme temperatures, humidity, and vibrations, can affect the BMS’s performance and reliability. Prolonged exposure to harsh conditions can cause the BMS components to degrade, leading to malfunctions.

Battery Age

As batteries age, they lose their ability to hold a charge and their overall performance declines. An aging battery can cause the BMS to struggle with maintaining optimal performance, leading to malfunctions.

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Symptoms of BMS Malfunction

A malfunctioning BMS can manifest in various ways, depending on the specific issue affecting the system. Some common symptoms of BMS malfunctions include:

  • Battery Management System Malfunction warning on the instrument cluster
  • Reduced driving range in electric vehicles
  • Longer charging times than normal
  • Inaccurate state-of-charge readings
  • Battery overheating or excessive temperature fluctuations
  • Premature battery degradation and reduced lifespan

Possible Solutions for BMS Malfunctions

If a BMS malfunction is suspected, there are several possible solutions to address the issue:

Check the Battery

The first step in addressing a BMS malfunction is to inspect the battery itself. In some cases, the issue may be related to the battery’s age or incorrect specifications, rather than the BMS.

Test the battery using a tester or visit a local auto parts store to have the battery and charging system tested for free.

Inspect the BMS Hardware

If the battery is in good condition, the next step is to inspect the BMS hardware for any visible signs of damage or wear.

This may involve checking the circuit board, connectors, and wiring for any issues.

Update Firmware

In some cases, a BMS malfunction may be due to outdated or buggy firmware. Contact the manufacturer or authorized service center to inquire about firmware updates for your specific BMS.

Perform a BMS Reset

For certain BMS malfunctions, performing a reset can help recalibrate the system and resolve the issue. This process typically involves discharging the battery to a low state of charge, allowing it to stabilize, and then fully charging it.

Consult your vehicle’s owner’s manual or contact the manufacturer for specific instructions on performing a BMS reset.

Seek Professional Assistance

If the issue persists after attempting the above solutions, it may be necessary to seek professional assistance from a qualified technician or authorized service center.

They can diagnose the problem more accurately and recommend the appropriate repair or replacement.

Preventing BMS Malfunctions

To minimize the risk of BMS malfunctions, it is essential to follow proper battery maintenance practices and adhere to manufacturer guidelines. Some tips for preventing BMS malfunctions include:

  • Regularly inspecting the battery and BMS components for any signs of wear or damage
  • Ensuring the battery is charged and discharged according to manufacturer recommendations
  • Avoiding exposure to extreme temperatures and other harsh environmental conditions
  • Keeping the battery and BMS clean and free of dirt, dust, and corrosion
  • Updating firmware as recommended by the manufacturer


What is the difference between a deep cycle and a Q85 battery in a Mazda?

A deep cycle battery is designed for running accessories and does not start the engine, while a Q85 battery is intended for starting the engine and managing the idle-stop-start function.

Why do electric vehicles require a BMS?

Electric vehicles rely on the battery pack to provide power for driving and all other electrical systems. A BMS is essential for ensuring the battery operates safely and efficiently, maximizing driving range, and prolonging battery life.

How can I reset my car’s BMS?

Resetting a car’s BMS typically involves discharging the battery to a low state of charge, allowing it to stabilize, and then fully charging it. Consult your vehicle’s owner’s manual or contact the manufacturer for specific instructions.

How long does it take to reset a BMS?

The time it takes to reset a BMS will depend on the specific vehicle and BMS model. However, the process usually takes about the same amount of time as it normally takes to recharge the battery.

Can I drive with battery malfunction?

Yes, you can drive with a battery malfunction. However, it’s not recommended to drive with a poor battery as it can cause your car to stop working unexpectedly while driving, which could be dangerous.

Whether or not you can drive with a battery malfunction depends on the severity of the problem. It’s best to have your battery checked by a professional to determine if it’s safe to drive with or if it needs to be replaced.

How do I know if my car battery is failing?

If your car battery is failing, you may notice several signs such as dim headlights, clicking sounds when turning the key, slow crank, needing to press the gas pedal to start, and backfiring.

Backfiring can also be a symptom of other issues, so it’s important to get a battery test to confirm. You can test your battery’s voltage with a multimeter by hooking it up to the positive and negative terminals.

If you see a blue-green powder or crystal-like substance caked on the terminals, it’s time to replace your car battery.

In case you notice any of these signs, it’s not recommended to drive with any type of malfunctioning battery as it could be dangerous and lead to problems with the car’s electrical system.

Does frequent charging damage car battery?

Frequent use of DC Fast Charging can negatively impact battery performance and durability, as noted on the Kia Motors website. However, according to a study conducted by the Idaho National Laboratory (INL), while an electric car’s battery will deteriorate faster if its only power source is Level 3 charging, the difference isn’t particularly pronounced.

It is worth noting that DC charging only increases battery deterioration by about 0.1 percent on average. That being said, it is not recommended to drive with a malfunctioning battery, as signs of a failing battery include dim headlights and a slow crank.

If you suspect that your battery is failing, it is best to have it checked by a professional and replaced if necessary

How long can a car charge a dead battery?

It will take between 10 to 24 hours to recharge a car battery fully using a typical charge amp of 4-8 amperes. However, a deeply discharged battery, given 15 to 30 minutes on a 40-amp charger, should be able to start the car, giving the alternator a chance to finish charging the battery.

If you want to boost the battery enough to start the engine, it would take about 2-4 hours, or you could use another vehicle to jumpstart it.

It’s important to note that different chargers take different amounts of time to fully charge a battery, and a high-power boost charger charges faster than a 1-amp float charger.

It’s also important to maintain the battery to extend its life, including driving at least 30 minutes straight each week and using a trickle charger when the car isn’t being driven.

Does driving faster charge battery faster?

Driving faster may charge the battery faster in some scenarios where the battery is significantly discharged. However, this is not a steadfast rule and it’s better not to rely on driving around to charge the battery.

The battery will charge faster if the engine is revved faster, it is not recommended to do this for a weak or dead battery. Instead, it’s better to use a battery charger to charge the battery overnight. Regularly testing your car battery is necessary, and conducting basic routine maintenance is advisable.

If the battery is not working well, it is recommended to buy a new one. It’s important to maintain the battery to extend its life, including driving at least 30 minutes straight each week and using a trickle charger when the car isn’t being driven.

Fix Battery Management System Malfunction >> Check out the video below:


A Battery Management System is a critical component in electric vehicles and other devices with rechargeable batteries. Proper maintenance and understanding of BMS malfunctions can help prevent issues and ensure optimal battery performance. By recognizing the symptoms and causes of BMS malfunctions and implementing the appropriate solutions, you can extend the life of your battery and maintain the safe and efficient operation of your electric vehicle or device.

Stephan K.

I have been working as a mechanic for over 13 years and have been deeper into advanced automotive diagnostics for some years.

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