Car Key Batteries Explained: What Every Driver in South Africa Needs to Know

 

Why Car Key Fob Batteries Matter

Imagine this: its early morning in Johannesburg, you rush out, press the unlock button on your key fob—nothing happens. The car doesn’t unlock. You try again. Still nothing. Then you realize the key fob battery died.

That moment is annoying, maybe stressful, perhaps embarrassing. But here’s the thing: this happens often, and most of the time you don’t need to take the car to the dealer or spend much money. Just knowing what the battery is, how long it lasts, how to replace it, and how to avoid surprises can save you time, frustration, and money. By the end of this post, you’ll understand everything about key fob batteries and feel confident fixing or replacing yours.

 

What Is a Car Key Fob Battery?

A car key fob battery is a small battery inside your remote key fob (that little remote you use to lock/unlock your car, sometimes open the trunk, or trigger alarms). It gives power to small electronics inside the fob.

Common uses of the battery

·         Locking and unlocking your car doors

·         Opening the boot

·         Triggering car alarms

Sometimes with push-start cars or smart key systems, starts or enables car ignition features

 

How Long Do Car Key Fob Batteries Last?

·         Average lifespan (3-4 years)

·         Most key fob batteries last about 3-4 years under normal use. If you use the fob often (remote start, alarm, frequent unlocking from far distances), battery life may be shorter. If you use it less, it might last longer.

For example, many owners of CR2032 coin-cell batteries report 3 to 4 years of use before the remote starts acting glitchy.

 

Factors that affect battery life

·         How often you press buttons on the fob

·         How far away you are when you press the button

·         Temperature (very cold or very hot drains battery faster)

·         Quality of the battery (brand, chemical makeup)

·         Whether the remote has extra features (like remote start)

 

Real-world example from drivers

One driver said their fob battery lasted 4 years. When it died, they couldn’t unlock using the remote, alarm went off trying to open manually, causing noise and attention until a spare fob came. Moral: having a spare and knowing the signs helps.

Another said CR2032 batteries used in their fobs lasted 2 years with regular usage. Some say they replaced more often if they unlocked from far or used extra features.

 

Signs Your Car Key Fob Battery Is Dying

·         Doors lock/unlock only when very close to car

·         Remote works some times, fails others

·         Delay when pressing buttons—press once, then again, maybe many seconds later works

·         Some features stop working (like boot open) but others still work

·         Completely unresponsive remote

If you see these, battery might be weak. Before replacing the whole fob, check battery first.

 

Types of Car Key Fob Batteries

Here are kinds you'll likely encounter.

Type	What it is	Pros	Cons
Lithium coin cell	Small round non-rechargeable batteries	Long lasting (3-5 years), compact, widely available	If low quality, drains fast; wrong size won’t fit
Alkaline batteries	Older style, less used now	Cheap and easy to find	Shorter life span and not common in modern keys
Rechargeable batteries	Built into luxury fobs and charges from the car	Less need to replace often	More expensive and the replacement is harder to do
Specialized batteries	Made by certain manufacturer for unique fob design	Designed specific to that fob	Harder to find and more expensive to replace.

 

How to Identify the Right Battery for Your Car Key Fob

·         Checking the car manual

·         Your vehicle’s handbook often tells you which battery type your key fob uses. That’s the safest route. 

·         Looking inside the fob

If you open the fob, you’ll often see the battery marked (size, code). Example: “CR2032” written on the battery itself.

·         Searching online by brand / model

You can search your car model + “key fob battery” and see what others use. For example, the most common battery for South African drivers is CR2032.

 

When to ask a locksmith or dealer

·         If battery type isn’t obvious

·         If fob is sealed or special unlock tool needed

·         If remote has extra features or uses different battery chemistry

 

Step-by-Step: How to Replace a Car Key Fob Battery

Here’s how most people do it. Be careful and gentle. Your fob parts are small.

1.       Find the correct battery

Get the exact type (CR2032 etc.)

Buy a good quality one, name brand if possible

 

2.       Open the fob safely

Find a seam, notch, or small slot where it splits

Use a small screwdriver or flat tool to gently pry open

3.       Remove and replace the battery

Note orientation: which side was facing up (plus / minus)

Remove old, insert new one same way

 

4.       Reassemble the fob

Snap the two halves together or replace screws

Ensure it closes fully, no gaps

 

5.       Test all buttons

Lock / unlock from different distances

Test all functions (trunk, alarm etc.)

Local anecdote: Johannesburg DIY

A friend in Sandton had a fob battery die. The local parts shop sold a CR2032 for R50. He opened the fob, swapped battery in 2 minutes, tested: lock/unlock worked fine.

 

Common Problems After Replacing the Battery

·         Fob still not working → maybe battery wasn’t fitted correctly or contacts dirty

·         Manual lock not reopening or unlocking → may be car hardware issue, not battery

·         Alarm honking or lights flashing when trying manual unlock → fob dead, car expects signal from fob; manual unlock triggers alarm

·         Wrong battery size used → doesn’t fit, loose contact

If battery replacement doesn’t fix, consider getting professional help.

 

Tips for Extending the Life of Your Key Fob Battery

·         Buy spare batteries and store safely (cool, dry place)

·         Don’t press buttons when far away, or unnecessarily

·         Keep fob away from extreme heat or moisture

·         Use spare fob occasionally so main fob battery usage is distributed

 

FAQs About Car Key Fob Batteries

Can I drive if my fob battery dies?

Often yes, by using mechanical key inside fob or emergency procedures in start button area. But remote features may not work, and alarm may be triggered in some cases.

What happens if I lose my spare?

Replace spare, treat it like main fob battery. Better to have two fobs than zero.

Do expiry dates on batteries really matter?

They matter for how fresh battery is. But how long it lasts depends more on usage, quality, and conditions. Expiry is quality-control measure. Battery may still work long past expiry if well stored.

Should I replace both fobs at the same time?

Good idea if both have same age, so you have backup. But not strictly necessary — just make sure the spare also has good battery.

 

Conclusion – Staying Prepared with Car Key Fob Batteries

Car key fob batteries play a small but big role: without them, your car may lock you out or refuse to unlock. They typically last 3-4 years, but this depends on usage, features, and battery quality. If you notice signs like reduced range, inconsistent response, or total failure, replacing the battery is the first step. It’s easy to do yourself using a good quality coin cell battery, a small tool, and careful reassembly. Keep a spare battery or spare fob, store batteries well, and be gentle with your key fob. With a little care, you can avoid many frustrations and drive with peace of mind.