Trouble with your car not starting? Could it be due to the key battery failing? Amazingly, yes. We’re going to look at the problems with your smart car key battery.

smart car key battery


With many of the latest models having keyless car keys, we’re taking lots of calls from stranded motorists who don’t know what to do. By the end of this article we hope you understand how important a good quality smart car key battery is.

How Does a ‘Smart Key Work?

If you have a push button start, instead of a lock that you put the key into, then this is for you.

There are two options you may have

  • Keyless Entry. The car sits and waits to detect that the smart car key is near. When is registers the key, it automatically unlocks. Or you may have the simpler version.
  • Keyless Start. This is a more basic system. With is this option you have to press the unlock button on your car key to get into the car. However, once your inside the car, it’s close enough that the car will sense the key inside the car.

With both of these features the car must detect the key, and here lies the problem.

Cheap Smart Car Key Battery Problems

It doesn’t make sense that a £15,000 car, with a £250 key has a 99p key battery fitted inside it. Unfortunately this is what we see every day. I can’t explain the technical reasons why a good quality smart car key battery is important. All I can say is that when we fit a good branded key such as Duracell, Maxell, Sony or Panasonic, the problems go away.

What does a cheap ‘nasty’ car key battery look like?

These are car keys that we removed from keys. They all caused problems with the smart car key system. Maybe we were just unlucky with these brands, and I’m sure they are fine in other devices such as door bells etc. But for car keys, they just don’t cut it.

Where can I get a good quality car key?

Do you know what type of car key you need? We’d recommend you find out before you start taking the key apart. We have a YouTube channel with over 150 videos that most likely have your car listed.

YouTube Car Key Help

Once you know what type of key battery you need, and you’ve watched how to change it, you’ll find a good range of high quality car key batteries at our Amazon shop. Or visit our resources page that has everything you need.

It’s too late, My Car Won’t Start

So if you’re stranded somewhere because your car cannot detect the car key, don’t panic. All car manufacturers realised early on that you would have this problem. They knew at some point you would have problems with your smart car key battery.

They designed the car so you could carry out a ‘car key emergency start’

Inside the car is a transponder chip, just the same as the ones inside a cat or dog. This chip helps the vet identify your pet. Well the car key is the same. The car can still detect the chip and let you start the car.

How Do I do a Car Key Emergency Start?

It all depends on what make and model you have. Even within the Ford brand, there are several different ways. So here’s a few models for you.If your car isn’t listed, then the handbook should help.


With Ford, there are lots of different ways the emergency start works. We’ve listed as many as possible in the article which covers most. Click here to read more.


This is our most viewed website page, with 300 Nissan owners viewing it every day! Join them and get prepared for when your smart key gets troublesome by clicking here


Keyless VW Passat Won't Start

Smart keys are a new venture for Volkswagen, but already we’ve taken calls about the new Passat and it’s keyless system. Read out latest article about how to do a car key emergency start on a VW Passat.

Citroen and Peugeot

Not many keyless cars from these makes, but one does get out notice. The keyless version of the Peugeot 108, or new Citroen C1.

If your car has this type of car key, then you should find out how to get it running when the smart car key battery lets you down. Click here to find out more

So that’s it for now. We’ll add more cars as we find them, and I hope you find this useful.

Remember, get a good quality car key battery and save yourself all the trouble we see of customers stranded.

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