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  • Max Kelly

What Battery for My Car Key?

When the battery in your car key starts to lose its charge, it's important to know the right replacement battery to keep your key functioning smoothly. In this blog post, we'll guide you through the process of selecting the appropriate battery for your car key.


What Happens When Your Key Fob Battery Is Low?

A dead battery in your key fob means that the key is unable to transmit any signal to the carโ€™s receiver. This will mean the car is unable to be unlocked using the key remote function, and keyless entry cars will be unable to start.


If you suspect your key fob battery is low on charge, you may notice the following:


  1. The fob may start to become unresponsive, and it may take several clicks for the remote function to be carried out.

  2. The range may decrease; you may notice you have to be close to the vehicle for the signal to transmit.

  3. In cars with push-button start, the car may not recognise a key fob when the battery is weak.


How Do I Know What Battery My Car Key Needs?

The most common batteries used in car key fobs are CR2032 and CR2025 3-Volt batteries.


To find out which battery you fob carries you can check the cars instruction manual, where this information will be listed. Alternatively, you can open your fob and check the battery itself.


How Long Do Batteries Last in A Key Fob?

A CR2025 battery in a car key fob may last up to 3โ€“4 years before needing replacement.


However, the CR2032 battery in a car key fob may last up to 4โ€“5 years before needing replacement.


The 2025 battery generally has 165 mAh, while the 2032 battery has 225 mAh, meaning it has a slightly longer battery life than the CR2025.


Where Can I Buy a Replacement Battery?

If you are unsure of the battery needed for your car key fob, we at Keytekยฎ Auto Locksmiths can help!


Book an appointment or call us to get immediate roadside assistance.




If you want to try and fix the problem yourself, you can find batteries online and in-store at places such as Halfords.

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