Key fob battery

[Rolfe]

Just a couple of days after my car's third birthday (and at about 31,500 miles) I got a low key battery warning on the dashboard. I just popped a new battery into the fob and all seems well. Is this the sort of life span others have been experiencing?

 

[MG Clive]

The keyfob battery is supposed to be changed every two years when it's serviced, so MG must reckon on a less than three year lifespan.

 

[siteguru]

At 2nd service I gave the dealer both my keys, on the basis that the batteries were supposed to be changed. Whether or not they actually did I've no idea, but I've not had any such warnings, and my car is ~6 months old than @Rolfe's.

 

[Rolfe]

I have never given both keys to a dealer. The other key, which I was using day-to-day, had an accident within the past year, and so what I'm using now is the one the dealer never had while the car was being serviced. Well, OK that's not true, Central Garages had it a few days before that for its third service, but obviously didn't do anything with it.

Anyway, it only takes a couple of minutes to pop a new battery in. I just wondered if three years was par for the course.

 

[Everest]

I just wondered if three years was par for the course.

IME yep.

 

[Rolfe]

Thanks.

Beats the other key fob, in which a battery lasts three DAYS since its accident.

 

[Lovemyev]

I just wondered if three years was par for the course.

Sounds about right tbh, but it does vary from manufacturer to manufacturer and even down to different models !.
I have owned about 6 new VAG models and the fob batteries lasted over three years, but our last VW was a Golf GTE PHEV with the keyless entry system.
It’s a strange design because the key sends a message to the car brain every few seconds when the car is in use.
You can see this happening, because there is a small red led light in the fob, that blinks every 5 to 10 seconds.
As a result of this constant drain, it eats through fob batteries about every 12 months.
The shortest time was 7 months !!!.
Spoke to the master tech at VW and he said that it was common with this type of system.
He also advised me to replace the battery as soon as you get the message on the dash.

 

[wandle MG4]

It’s reassuring a message comes up on the dash alerting you to a low battery.

I handed both fobs over at the 2 year service and discreetly marked the batteries. They were both swapped for new ones.

It’s worth checking the blade key is still present every time a dealer has had the fob.

 

[Rolfe]

It's possible my original dealer did change the battery in the key I gave them for the 2-year service. I have no way of knowing, as that's the key that subsequently had the accident. They never asked me for the other key though.

Central Garage obviously didn't change the battery in the key they had (the one the original dealer never had) for the 3-year service, because I got the low battery warning a few days later. However, if the battery-replacement thing is only supposed to happen every two years, he wouldn't have been expected to.

I did ask him for the price of a replacement for the faulty key, and it wasn't too bad because I still had the emergency mechanical key, and he said that was the really expensive part. But as he said, if the key works normally for three days if you put a new battery in it, it still functions as a spare key, so why bother?

 

[EvTek23]

3 years is fine, but they change them at 2 years to avoid issues.
I normally give the garage my spare key which hardly gets any use and they duly changed the battery on its second birthday. Realising this, on its 3rd birthday (a month or so ago) I gave them both and each were changed. I like to keep one key......just in case when the garage have the car, I feel it gives you some leverage in case of disputes.
It's worth getting a decent brand such as Energizer, from a shop or reputable on line seller. I think some have bought what they've thought to be a good make on line only to find they are failing prematurely as they're probably counterfeit.