UniEnergy Technologies Battery » What Size Battery For Key Fob? (Recommened Size & Repalcement Tips)

What Size Battery For Key Fob? (Recommened Size & Repalcement Tips)

Key fobs have evolved over the years. What began as a convenient way to unlock and lock doors remotely has changed into an advanced push-start system. Even though key fob technology is ever-evolving, its power source remains constant. Auto remote systems such as key fobs are battery-powered. So, when the battery in them dies, it should be replaced. If you’re in this situation, you’re probably wondering about the battery size for key fobs.

CR2032 is the most common battery for the key fob. The numbers indicate its diameter or width and height or tall. That means this battery has a width of 20mm and a height of 3.2mm. Most people wonder what kind of battery their car key fob requires. What’s the recommended size when purchasing a new battery for the fob?

Read through to answer all those questions!

What Is the Recommended Battery Size for the Key Fob?

For most cars, the CR2032 is the recommended key fob battery. It’s a prevalent choice due to its durability, deep discharge capacity, and affordable price. If you are not sure what size battery your key fob uses, most websites share information about the standard battery size of your car model and year of manufacture.

The question of what size battery for the key fob always pops up when you intend to purchase a new key fob battery. Sometimes we tend to talk about the model and forget about the year of manufacture. If you look at the recent car models (for instance, 2018, 2017, 2016, and 2015), the batteries come with the exact dimensions. While they might feature different colors, this doesn’t change how they are utilized.

Since the batteries for these years are the same type, you can use them for four years. What type is your better option一the inexpensive replacement or higher quality replacement?

In most cases, replacement batteries for remote key fobs are better than original batteries. When you purchase a new high-quality replacement battery from Amazon you’ll have no issues unless you get a cheaper replacement battery. Inexpensive replacement car fob batteries will fail faster.

Signs That You Might Need Key Fob Battery Replacement

Signs That You Might Need Key Fob Battery Replacement

Even when the fob tends to be working well, some irregularities occur as the battery dies. You might likely be dealing with these problems without noticing. And these inconveniences will eventually result in serious issues.

  • Reduced signal range: An optimal key fob has a signal of up to 60 feet. But if the remote’s battery dies, it will affect the fob’s working range. If you’ve realized that your key fob needs you to be near the car more than before, or it’s not transmitting a signal from the other end, as you bought it, it’s time for a new battery.
  • Inconsistent clicks: You might notice that you must press the button on the fob several times before your car responds to the signal. When that occurs, the fob battery experiences a hard time mustering the needed power to run. When this happens to you, you should consider replacing the battery ASAP. Some fobs are meant only to lock and unlock doors, while others are needed to initiate the push-to-start ignition. If this part is inconsistent and needs several presses, the fob must be fixed.
  • Delays in unlocking: You may need to click the button once, but there is that delay before the door unlocks. That’s a sign the fob battery is dying. Your vehicle’s headlight might not blink when unlocking or locking the car. It might appear non-threatening now, but you’ll be in trouble if the fob suddenly fails to work.

How To Replace Your Battery in a Key Fob

How To Replace Your Battery in a Key Fob

Newer car generations come with a key fob, either as a separate gadget attached to the keyring with buttons to unlock and lock the car or incorporated into the car key. A fob allows you to control the car by sending a wireless signal and then operating on battery energy. While the battery can last up to 5 years, if the battery is weak, getting into your car or even starting it remotely won’t be possible.

The good news is you can replace the key fob batter easily.

Step1. Get the Batter Type Embossed in Plastic

On some fobs, the battery type is printed on the seal. That way, you can visit a store and choose the right battery sizes and type before even opening it. The three common brands of key fob batters are Panasonic, Energizer, and Duracell.

Step2. Locate the Seam Where the Parts of the Fob Join Together

Most fobs open in the clamshell style, where the two join together. There is a seam where you can separate the two parts. Some fobs come with a notch along that seam. If your car requires you to insert the key in the ignition, ensure nothing is hanging from the keyring apart from the fob. That’s because the weight of your home keys might wear down the ignition chamber which is risky.

Step3. Lightly Pry at the Notch or Seam

When it comes to replacing a button cell battery for the key fob, you require one tool. Using a thin, small-flat-headed screwdriver, pry separate the two parts gently to open the key fob down the center.

Most modern cars with transponder keys and fobs can’t allow you to lock the keys inside your car. However, it would help if you were ready in case the worst happens.

Turn the key counterclockwise on the ON position, lift the dash, and open the cover to expose the key blade. Remove the metal plate to get access to the battery compartment.

Put the car key in the ignition to disconnect it from the car battery and leave it for some time to allow the battery to cool down. The car won’t remotely start without this key, and if you pull it out from the ignition, the car won’t start. The car won’t turn on in that state without pressing the e-lock button.

Detach the metal plate on the panel to access the fob battery. Squeeze the clips on the two sides of the plate and pull down on it.

Step4. Check Out the Battery Orientation (Negative and Positive Ends)

Step4. Check Out the Battery Orientation

The battery resembles a coin; hence they are called coin cell batteries, and it’s marked with the battery size and comes with a minus and plus sign. Note which direction the fob battery is oriented. When you buy a battery of a similar size, it should go in a similar way.

Step5. Remove the Old Battery and Put in the New One

In most cases, the battery for the Nissan key fob will pop out of its place once you press it. If it’s stuck, use the small flathead screwdriver to remove it. Insert the new battery at the position of the old battery with a similar orientation of the negative sides face and plus signs.

Step6. Snap the Fob Shut and Try Its Function

Assembly is the opposite of disassembly. So, snap the smart key fob back together and try out the buttons. Re-attach the metal plate to restore access to the fob and return it to its place. Everything should be functional.

Insert the key into the ignition and turn it counterclockwise to the ON position such that it can reconnect with the battery system of your car.

Step7. Reset the Key Fob

After replacing the battery, you’ll need to program your key fob. First, start the car engine and make sure all doors are closed. Relax in the driver’s seat with the key fob and ignition key. Press on the lock option and turn off the engine. Then get out and try the key fob.

Things To Remember When Replacing Your Fob Battery

When replacing the battery for the key fob, you need to be vigilant not to destroy the internal parts. For instance, you need to unplug the remote battery before removing the panel’s metal plate. This is to ensure you won’t accidentally short out the wires. It’s also important to be careful when installing the battery in your car to ensure you don’t cut the wires and cause severe issues with your car.

In most cases, a new fob battery is included in the kit, and you can use it to replace the dead battery. There are numerous battery brands on the market, such as Panasonic. It’s a rechargeable nickel lithium metal hybrid with a 1200 mAH capacity.


A key fob is a gadget you can attach to keys and other items. It controls track movement and access to your car. If it fails, you need to know the key fob battery size to ensure you get the right fit. Use proper safety tools like eyeglasses and gloves when replacing a key fob battery. This will assist you in evading any accident while undertaking this project. The process of replacing the battery involves these steps:

  • Remove the key if it’s in the fob
  • Unbolt the back of your fob
  • Twist a coin in the notch if the fob has it
  • Remove the key fob cover if it doesn’t have a slot
  • Use a screwdriver to pay out the battery
  • Put the new battery in place
  • Screw the key fob back into its place
  • Test the key fob

For any questions regarding the battery size of the key fob, leave your comments below!

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