How Long Does a Key Fob Battery Last?

It’s possible to remotely lock and unlock your doors, operate your windows, and even start your car with a modern car key fob.

Like all remote controllers, car keys can only work when there is sufficient battery power.

How long do car remote batteries last? We researched to give you a good reading experience.

Modern car remote batteries typically last between three to four years, depending on the usage.

If you would like to know more about your car remote’s battery as well as your car’s key fob, then you’ve come to the right place. We will help you understand more after you read on.

Key Fob with battery

How Often Do I Need To Replace My Car’s Remote Battery?

The CR 2032 is one of the most popular car key remotes and key fobs.

Different coin batteries, such as the CR2450, CR2025, and CR 2016 are used for key fobs. The batteries have the same voltage but are different in size and capacity.

A CR2032 has a diameter of 20mm, a thickness of 3.2mm, and a charge capacity of 240mAh.

CR2450 has a 24mm diameter, 3.2mm thickness, and a charge capacity of 486mm. The thicker the coin battery, the longer it can last.

Some key fobs can work from a maximum range of 15 feet, while others can only work from 100 feet.

The window operation is one of the key fob commands which requires long button presses. More range and longer button presses can lead to more power consumption.

Key fob manufacturers use an appropriately-sized battery that can handle their power requirements for years of normal usage.

The shelf life of coin batteries is 10 years after production.

The batteries may lose their charge or fail to function after a decade if they remain unused. The coin batteries can last up to four years under normal use.

How To Identify If a Key Fob Needs A New Battery?

You will notice some signs of a weak battery when you use your key fob.

Shorter Signal Range

Your car won’t respond to the button commands from the same distance as it did before.

It’s possible that your battery doesn’t have enough power to send the signal from the same distance as before.

It may be a good time to replace your battery if you need to be standing by your car.

Repetitive Button Presses

Sometimes a single button isn’t enough to start your car, lock your car, or unlock your car.

Your battery might be getting weaker if your car’s response to your key fob buttons isn’t consistent.

Delayed Response

If your car’s response is slow or delayed, you may not be able to sustain the remote signal.

Your battery may be weak if you have to press and hold your key fob buttons to make your car respond to normal commands.

Which Is the Culprit: Key Fob or Battery?

Dead batteries are often the cause of failing keys, but the key fobs themselves can sometimes malfunction.

If you want to find out what’s wrong with your battery or key, you can try it out before you replace it. You can save some money if you follow these helpful tips.

Test Your Spare Key Fob

One of the easiest ways to check a failing key is to have a spare key. Modern cars usually have two keys, one for the driver and one for the passenger.

If the spare key doesn’t work, then you know that the main key isn’t working.

Check If Your Key Fob Is Transmitting

You can use a radio frequency remote tester to determine if your key is sending out an RFID signal. The remote tester can also determine the signal frequencies of your key fob.

Use Your Television

You can use a smart T.V. if you know your key fob’s signal frequency. To help you test your transmission.

Here are the steps to use a smart T.V. for the testing of your keys.

  • Turn on the smart T.V.
  • Go to Settings > “Tuning,” > “Manual Store,” > “Search.”
  • Under “Search,” choose the key fob’s frequency.
  • Bring your key fob near T.V., then press a key fob button.
  • If the smart T.V. ‘s screen is disrupted by your key fob, that’s a positive thing.

In Japan and the U.S., key fobs use a 315 MHz signal, while in Europe, they use a 433.92 MHz signal.

Interpret The Results

You can use either of the methods above to figure out the problem with the key fob.

The car does not respond to the buttons if all of them are transmitting, then:

  • Reprogram the key fob.
  • There’s a problem with your car’s remote keyless entry module or body control module.
  • Some blown fuses.
  • The battery is discharged.

If key fob buttons work or transmit weakly then it is the result of a weak battery.

The car doesn’t respond to all button commands if all of your key fob buttons transmit a signal, then:

  • Reprogram the key fob.
  • The car’s RKE module or BCM has some problems.
  • The car’s electromechanical parts have problems.

If only some buttons transmit, but the car responds to them, then:

  • The key fob may be accumulated with dirt.
  • The key fob’s circuit board may have some dirt.

If none of the buttons are sending any signals, then:

  • The key fob’s battery is discharged.
  • RFID transmitter is damaged.
  • The Circuit board might be dirty.
  • You need a new key fob.

You can still test the battery’s state of charge if you interpret your results and link the problem to the battery.

Is it weak or is it completely discharged? The next section will give you some information.

Key Fob


The batteries of a car remote or key fob can last up to four years. The battery life may be shortened by improper key fob usage. You should always take care of your key.

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