Key Points To Remember
- Symptoms like reduced operating range or inconsistent response and a dim or unlit LED can indicate a weak battery, but may also have other causes.
- Car keys come in different types, such as standard keys with separate remote fobs, static blade remote keys, remote flip keys, and smart/proximity keys, each requiring their respective batteries and handling procedures for replacement.
- For effective battery replacement, gather the proper tools, carefully open the key fob, replace the battery while ensuring correct orientation, and reassemble the fob finally checking its functionality.
Recognising the Need for a Car Key Battery Replacement
Is your car key fob not responding as it used to? This could be an early sign that your car key battery needs to be replaced. Some symptoms to look out for include reduced operating range or inconsistent response, such as needing multiple button presses. These signal that the car key battery is weakening.
If the LED light on your key fob is faint or doesn’t illuminate when buttons are pressed, or you notice a decreased signal range, it can be a subtle indication of a dying battery. No response or considerable delay when attempting to unlock the vehicle, can indicate a weak battery, interference, damaged buttons or another fault.
Identifying Your Car Key Type
Before we dive into the battery replacement process, it’s crucial to identify your car key type. Car keys come in a variety of forms, each with specific battery needs and features that need to be considered during replacement. By accurately determining your key type, you can ensure you choose the appropriate battery.
Common replaceable key-fob cells include CR2032, CR2025, CR2016, CR1620 and CR2450. Different keys from the same manufacturer can use different cells, so do not choose a battery by brand alone. Match the exact markings and specification in the vehicle handbook or on the existing cell. Some sealed or rechargeable keys are not designed for routine battery replacement.
Keep new and used button cells away from children and pets. A swallowed button battery is a medical emergency: seek urgent medical help immediately. Some older BMW slot keys use a rechargeable internal battery and may need a replacement key rather than a routine cell change.
Let’s explore the four common types of car keys: standard keys, static blade remote keys, remote flip keys, and smart/proximity keys.
Standard Keys
Standard car keys are the traditional type that most of us are familiar with. These keys are symmetrical and may have grooves on both sides or channel track cut into the middle.
Standard keys on their own lack the ability to open and close the vehicle from a distance. They are often found as they are but can be accompanied by a separate remote fob attached to the key ring.
These keys can:
- Open car doors via the door lock
- Start the ignition if containing an RFID Transponder Chip
- Open the glove compartment
- Sometimes even open the trunk if there is a trunk lock available
Non Flip Remote Keys
Unlike their flip counterparts, these keys maintain a static form, with the key blade and electronic components encased in a durable shell. They offer the convenience of having more room in your pocket or bag by removing the extra chunkiness caused from requiring two separate elements to your car key.
The absence of moving parts, as seen in flip keys, minimises wear and tear, potentially increasing the longevity of the key. the main downside to non flip is the blade is susceptible to snapping which is what the flip key aims to solve.
Remote Flip Keys
Remote flip keys combine the traditional key and modern convenience of remote access in a compact design. With a press of a button, the key blade flips out, ready for use and integrated into the key body buttons for remote locking and unlocking. They're particularly useful for quick access and offer a modern solution to car security without complicating the user experience.
Many remote flip keys use a CR2032, but other sizes are also used. If there is uncertainty about the correct battery, consulting the vehicle handbook, dealership or an auto locksmith can ensure the correct specification is identified.
Proximity Keys & Smart Keys
So, what exactly are smart keys? They are technologically advanced keys that enhance convenience by allowing drivers to keep the key fob pocketed for unlocking, locking, and even starting the vehicle. This is made possible by antennas in the vehicle’s bodywork and a radio pulse generator in the key.
Vehicles equipped with smart keys can disengage the immobiliser and activate the ignition via a push button or a twist switch, eliminating the need for inserting a key. Smart keys provide user customisation by adjusting preferences like seat positions, steering wheel position, and temperature settings when unlocking the vehicle. It’s essential to consult the owner’s manual for specific details on how to operate and customise your smart key system.
Gathering Necessary Tools for Battery Replacement
The tools needed depend on the exact fob design. A manufacturer-approved access point, release tab or small retaining screw may be used. Some keys need a suitable plastic opening tool or the specified screwdriver. Do not use pliers or excessive force to open a stiff case: a sealed or rechargeable key may not be designed to open for routine battery replacement.
Check the vehicle manufacturer’s instructions before attempting to open the fob. If the access point is unclear or the case resists, stop and ask a specialist rather than damaging its clips, circuit board or transponder.
Accessing the Car Key Battery
Battery access varies between separate remotes, fixed-blade keys, flip keys and proximity fobs. Some have a small screw or removable battery cover; others have a release hidden by the emergency blade. A seam alone does not prove a case is meant to split. Follow the instructions for the exact key instead of assuming all flip keys or non-flip keys open in the same way.
Some smart keys have a removable emergency blade that reveals the battery-cover release. Consult the handbook for the exact access method. A video for another model or key generation is not a reliable substitute for those instructions.
Once the key fob is open, check the existing battery type and specifications in order to match the replacement car key batteries exactly, using a slightly different size will not work.
It’s vital to handle your car key and its components gently throughout the battery replacement process to avoid damage.
Seam or Notch Location
To open the fob, you need to:
- Locate the seam or notch.
- Remove any physical key from the fob if applicable.
- Inspect the edges of the fob, potentially in the cavity where a removable key resides, or along the top, bottom, or sides.
- Some key fobs may require the use of a special tool or the key itself to release a clip for the fob to open.
Gently Prying Open the Fob
Where the manufacturer specifies an opening point and a user-replaceable battery, use the recommended access method gently. Avoid levering against the circuit board or battery contacts. If it does not release as described, stop rather than forcing the halves apart.
Sealed and rechargeable fobs need specialist assessment rather than repeated attempts to pry them open.
Replacing the Old Battery with the New One
With the key fob open, it’s now time to replace the old battery with the new one. Car key batteries, including key fob batteries, come in various sizes as per the few examples stated above, they are denoted by a series of numbers, and it’s important to match the right size for your key.
Here is a list of some of the many Button Cell Battery types
- CR2032
- CR2025
- CR2016
- CR1620
- CR1220
- CR2450
- CR2430
Removing the Old Battery
Before attempting to remove the old battery, observe whether it is held in place by a retaining clip or if it simply rests inside the battery compartment. If the old battery is secured with a retaining clip or a small metal tab, carefully release it to avoid damaging any components of the key fob.
Gently use fingers or a non-metallic tool to lift the old battery out of its compartment, ensuring not to apply excessive force that could damage the key fob housing or the internal components.
Inserting the New Battery
Now, it’s time to insert the new battery. Follow these steps:
- Check that the new battery is free from any packaging or protective films before insertion to ensure proper electrical contact. If you have used a Duracell battery be extra certain you have removed the child safe sticker from the negative terminal.
- Slide the new battery into the slot ensuring the correct orientation.
- Press firmly to secure it in place so it sits flat within the battery compartment.
After inserting the new battery, follow these steps to complete the reassembly process:
- Align the cover of the battery compartment.
- Press the cover back into position, making sure it is securely in place.
- Use screws, if necessary, to further secure the battery compartment.
- Test the key fob functionality to ensure the battery is working correctly.
- Once you have confirmed that the key fob is functioning properly, the reassembly process is complete.
Tips for Prolonging Your Car Key Battery's Life
Good storage habits can help reduce avoidable battery drain and keep the key in reliable condition.
Temperature Control
The life of your car key battery can be significantly affected by the temperatures it is exposed to. Avoiding extreme temperatures is essential to extend the life of your car key battery.
Do not leave the car key fob in direct sunlight or in places like a car dashboard where it can get hot, as this can lead to faster battery drainage.
Minimising Clicks
Did you know that the more you click, the faster your battery drains? Therefore, it’s advisable to avoid playing with the car key fob or using it as a stress-relief toy to minimize battery wear caused by unnecessary clicks.
Visit your local store to find a suitable bag or purse with a dedicated compartment for storing the car key fob securely, reducing the likelihood of accidental presses.
Regular Check-Ups
Just like any other device, your car key fob requires regular check-ups to ensure it remains free from damage and functions properly. A car key fob battery typically lasts between two to three years under normal conditions, but smart key fobs usually have a shorter battery lifespan, ranging from one to two years, due to more frequent communication with the vehicle.
There are a few battery brands available we found this battery guide which list the different types and which brands are the strongest.
Troubleshooting Car Key Battery Issues
Even with the best care and maintenance, you may still encounter some issues with your car key battery. Regular check-ups for a car key battery should include measuring the voltage with a millimetre while the key fob is transmitting to ensure it is operating effectively. A more accurate assessment of a car key battery’s health can be obtained by using a cheap battery tester that applies a load on the battery while measuring the voltage.
However, if you find your car key quickly using up batteries or if you receive an incorrect ‘Key ID Incorrect’ message, it’s advisable to consult a specialist auto locksmith as a new fob may be needed. Physical damage to key fobs, including cracked casings or water exposure, often necessitates professional repair or seeking a car key replacement service.
Seeking Professional Help
While it’s great to be able to replace your car key battery yourself, there are times when professional help is necessary. If your key fob exhibits persistent weak or inconsistent signal strength that doesn’t improve with a new battery, or if its buttons remain unresponsive even after attempts at cleaning or battery replacement, it’s time to seek professional help.
Professional auto locksmiths are equipped with the tools and knowledge to repair or replace a car key, including faulty key fobs, and reprogram them, ensuring functionality with the vehicle’s electronic systems. They can also offer car key replacement and key duplication services , which may be more cost-effective than a dealership, depending on the key and vehicle, especially in case of lost or seriously damaged car keys that are beyond repair.
Summary
Throughout this article, we’ve covered everything from recognizing the need for a car key battery replacement to prolonging its life and troubleshooting common issues. Proper maintenance of your car key battery is crucial to ensure a hassle-free driving experience. Remember, a little effort can go a long way in extending the lifespan of your car key battery.