What are the signs my car key fob battery is low?

Common signs include reduced range, intermittent response, low battery alerts, push-start issues, and loss of remote functions.

What happens if I use the wrong battery in my key fob?

You may experience reduced range, damage to electronics, improper fit, battery leakage, or a shorter lifespan for the fob.

What battery do most UK car key fobs use?

The CR2032 lithium coin cell battery is the most common for UK car key fobs from 2011 to 2024. Mercedes-Benz often uses CR2025 instead.

What Battery Does My Car Key Fob Need?

Max Kelly
May 23, 2023
4 min read

Updated: Jun 20

Your car key fob is one of those essential items you use daily without much thought—until it stops working. When your key fob starts acting up, the culprit is usually a dying battery. Knowing which battery your specific car key fob needs can save you time, money, and the frustration of being locked out of your vehicle.

Key Fob Battery Types for Major UK Car Brands

When it comes to replacing car key fob batteries in the UK, knowing the exact battery type for your car’s make and model year is essential. Across the most popular car brands from 2011 to 2024, the CR2032 coin cell battery is the most used key fob battery.

Close-up image of an opened car key fob showing the internal circuit board and a round lithium coin cell battery connected with red and black wires.

Key Fob Battery by Brand and Model

Audi: Models like A3, A4, A5, A6, Q5, Q7, and R8 consistently use CR2032 batteries from 2011 through 2024. Newer models such as A1, A7, Q2, Q3, and Q8 (post-2015) also use CR2032 batteries.
BMW: Popular series including 1 Series, 3 Series, 5 Series, and SUVs like X3 and X5 use CR2032 batteries across all recent model years.
Fiat: Models such as 500, Panda, Punto, and 124 Spider use CR2032 batteries consistently, with newer models like Tipo (from 2016 onwards) also using CR2032.
Ford: Common models like Fiesta, Focus, Mondeo, and Kuga use CR2032 batteries, with Puma using CR2032 after 2015.
Jaguar: XF models use CR2032, while newer models like XE and F-Pace (from 2016+) also use CR2032 batteries.
Land Rover: Discovery and Range Rover use CR2032, while newer Evoque models (post-2015) use CR2032.
Mercedes-Benz: The key exception is Mercedes-Benz, where CR2025 batteries are standard for models like A-Class, C-Class, E-Class, and GLC from 2011 to 2024.
Mini: Cooper and Countryman key fobs use CR2032 batteries consistently.
Nissan: Popular models such as Qashqai, Juke, and Leaf all use CR2032 batteries.
Toyota: Models including Yaris, Corolla, and Prius rely on CR2032 batteries.
Vauxhall (Opel): Corsa, Astra, and Insignia use CR2032, with Mokka switching to CR2032 after 2015.
Volkswagen: Polo, Golf, Passat, and Tiguan use CR2032 batteries consistently.

To make replacing your car key fob battery even easier, we offer a free downloadable PDF guide. This comprehensive resource breaks down key fob battery types by make, model, and year, so you can quickly identify the right battery for your vehicle without any guesswork.

Full List of Car Key Batteries

Audi

Model	2011 - 2015	2016 - 2025
A1	N/A	CR2032
A3	CR2032	CR2032
A4	CR2032	CR2032
A5	CR2032	CR2032
A6	CR2032	CR2032
A7	N/A	CR2032
A8	CR2032	CR2032
Q2	N/A	CR2032
Q3	N/A	CR2032
Q5	CR2032	CR2032
Q7	CR2032	CR2032
Q8	N/A	CR2032
R8	CR2032	CR2032
S4	CR2032	CR2032
S5	CR2032	CR2032
S6	CR2032	CR2032
TT	CR2032	CR2032
TTS	CR2032	CR2032

BMW

Model	2011 - 2015	2016 - 2025
1 Series	CR2032	CR2032
3 Series	CR2032	CR2032
5 Series	CR2032	CR2032
X3	CR2032	CR2032
X5	CR2032	CR2032

Fiat

Model	2011 - 2015	2016 - 2025
500	CR2032	CR2032
Panda	CR2032	CR2032
Punto	CR2032	CR2032
Tipo	N/A	CR2032
124 Spider	CR2032	CR2032

Ford

Model	2011-2015	2016 - 2025
Fiesta	CR2032	CR2032
Focus	CR2032	CR2032
Mondeo	CR2032	CR2032
Kuga	CR2032	CR2032
Puma	N/A	CR2032

Jaguar

Model	2011-2015	2016-2025
XE	N/A	CR2032
XF	CR2032	CR2032
F-Pace	N/A	CR2032

Land Rover

Model	2011-2015	2016-2025
Discovery	CR2032	CR2032
Range Rover	CR2032	CR2032
Evoque	N/A	CR2032

Mercedes-Benz

Model	2011-2015	2016-2025
A-Class	CR2025	CR2025
C-Class	CR2025	CR2025
E-Class	CR2025	CR2025
GLC	N/A	CR2025

Mini

Model	2011-2015	2016-2025
Cooper	CR2032	CR2032
Countryman	CR2032	CR2032

Nissan

Model	2011-2015	2016-2025
Qashqai	CR2032	CR2032
Juke	CR2032	CR2032
Leaf	CR2032	CR2032

Toyota

Model	2011-2015	2016-2025
Qashqai	CR2032	CR2032
Juke	CR2032	CR2032
Leaf	CR2032	CR2032

Vauxhall (Opel)

Model	2011-2015	2016-2025
Corsa	CR2032	CR2032
Astra	CR2032	CR2032
Insignia	CR2032	CR2032
Mokka	N/A	CR2032

Volkswagen

Model	2011-2015	2016-2025
Polo	CR2032	CR2032
Golf	CR2032	CR2032
Passat	CR2032	CR2032
Tiguan	CR2032	CR2032

How to Replace Car Key Battery – An Auto Locksmiths Guide

Why It’s Important to Get the Right Car Fob Battery

Using the correct battery in your car key fob is essential for reliable performance, safety, and battery life. Car key fobs rely on specific battery types with the right voltage, size, and chemistry. Using the wrong one can cause reduced range, malfunctions, or even permanent damage.

Risks of Using the Wrong Key Fob Battery

Reduced signal range: Low voltage batteries may only work when you’re very close to your car.
Damage to electronics: A battery with too high a voltage can fry internal components.
Improper fit: Too-thick batteries won’t let the casing close, risking exposure to moisture. Too-thin batteries may lose contact with terminals.
Battery leakage: Cheap or alkaline batteries can leak over time, damaging your fob permanently.
Short lifespan: Lithium coin batteries like CR2032 or CR2025 are the most common for key fobs, typically lasting 2–4 years. Avoid lower-quality substitutes.

Signs Your Car Key Battery Is Low

Car key batteries usually give several warning signs before they die completely:

Decreased range – You need to be closer than usual to lock or unlock your car.
Intermittent response – The fob may work sporadically or need multiple presses.
Low battery alerts – Some cars display messages like “Key Fob Battery Low” or dim LED lights on the fob.
Push-start problems – Low battery can prevent your vehicle from recognising the fob.
Loss of remote functions – If the battery dies fully, only the manual key will work.

When to Replace Your Car Key Fob Battery

Most car key fob batteries last 2 to 4 years, depending on usage and environment. Replace the battery as soon as you notice issues—don’t wait for full failure.

Tips for Timely Replacement

During routine servicing or before a long trip.
When daylight saving time changes—replace fob batteries along with smoke detector batteries.
If you live in extreme temperatures, expect faster battery drain.
High usage (e.g., frequent locking/unlocking or remote start use) may shorten battery life.

Pro tip: Carry a Spare

Keep a spare CR2032 or CR2025 battery in your glove box. These batteries are small, cheap, and long-lasting—perfect for emergencies.

Also, if you have multiple key fobs, replace all their batteries at the same time. They’re often used equally and will likely fail around the same time.