Types of batteries used in a car key fob & how long do they last

Expiry date on key fob batteries are exceptionally well calculated. It will be better if you change the battery proactively, if it is reaching the expiry date.

BHPian MT_Hyderabad recently shared this with other enthusiasts.

Having the right spare battery for your key fob is critical for peace of mind on long drives.

I faced a similar challenge recently and realized the importance of checking the battery health.

My Tata Safari Dicor comes with 27A battery type.

I bought 5 batteries and changed both the key fob batteries in 2019, the expiry date mentioned on the battery was July 2022, which I didn't memorize by heart (mistake).

Few days back, the battery on my main key fob died and I started using the spare one(which is used only by car cleaner on weekends), unfortunately, it also died within two days. I replaced both the batteries with new ones from the set bought in 2019. I then noticed that the expiry itself is July 2022.

I immediately ordered a new set as the led on one of my key fob was showing low intensity, even with this new cell. I started carrying both the key fob and the remaining one unopened cell everywhere in my laptop bag. Not surprisingly, one key fob died within one day. I was lucky that there was still some charge left in the other.

Today, I received a new set and changed both the key fob batteries together. I didn't bother to test the untouched one from the previous set.

Learnings: Expiry date on key fob batteries are exceptionally well calculated. Please keep a tab on it.

It will be better if you change the battery proactively, if it is reaching the expiry date. The spare battery may die at the same time, even if it is an unused sealed-pack.

May I request everyone to mention what battery type their key fob comes with, and how long it lasted? This may help other BHPians.

Car: Tata Safari Dicor

Battery type: 27A

Years lasted: Full 3 years; till the expiry date mentioned on the battery.

Here's what BHPian Sushil Pingua had to say on the matter:

My car: Honda BRV MT Petrol, 2017 model.

My keyfob uses the CR2032 Button Cells.

The original batteries which came as OEM lasted for around 2 years. After that the batteries were replaced from the Honda authorised workshop and they lasted just over an year. So I decided to purchase these batteries from Amazon/flipkart which last around a year too.

I keep reserve pair of spare batteries in the car.

Here's what BHPian lapis_lazuli had to say on the matter:

Both my car key-fobs have CR2032 cells. The Punto key-fob is still on its original cell and it has been 10+ years.

The Superb remote needed change after about 1.5 years. Both the key fobs.

The cell pictures that OP has posted, I have seen them being used in home security remotes only. A learning for me.

Here's what BHPian Agarwal_Aayush had to say on the matter:

Both my car keys use CR-2032 button cells.

Interestingly, the one I use regularly is still working without any signs of low battery (5 years and continuing), whereas the spare one was dead and had to replace the cell after 2 years, I chose Duracell this time, original came with Panasonic make.

I now use them alternating on a monthly basis.

Car: MS Baleno 2017 make.

Here's what BHPian chillingmonk had to say on the matter:

I didn’t know key fob batteries have well-calculated expiry dates. I will sure go and check now for my 11 year old Hyundai i10 and 8 months old Jeep Compass.

I have been using the same key fob on my i10 since day 1, only for locking and unlocking the doors, and have never had to replace the battery. I thought that once this keyfob runs out of battery, the other’s life will start. Now I know how stupid that sounds. Having said that, since the ignition key on this key fob is our old fashioned, non-nonsense metal buddy, running out of battery suddenly will lead to a half sigh and a full shrug at best.

I can’t say the same about my modern Compass key fob. My jeep comes to life only with its beloved within touching distance, every single time. So, right away, I am going to check the expiry date of its batteries, and its hitherto unused twin. And I’ll probably keep the twin handy in some way, rather than safeguarding it with the full might of my closet.

Here's what BHPian IP_Man had to say on the matter:

My story.

Battery for my main key fob lasted for four years. I did not bothered much about it because I have spare key fob and I was under impression that car can be unlocked manually by dead battery in key fob because ECU can read RFID tag as it is passive.

One day, battery died. I tried to unlock car manually. Suddenly car started honking loudly and all turn indicator started flashing. It was embarrassing situation because everybody around me started looking at me suspiciously. Fortunately I was in my society, my wife brought spare key fob to rescue me from the situation.

Moral of the story, keep battery in the key fob updated.

Here's what BHPian Transmission had  to say on the matter:

Just wanted to highlight that the expiry date on the battery is for quality control purposes (and even then not exactly a hard date like the expiry date, say on a regular plastic milk packet) - and does not depend on the usage - in fact it assumes 0 usage.

In other words your key fob battery will last longer or shorter depending on how much you use it - the expiry date on the battery has not much to do with it once you start using it. Of course, chances are that it will not last that long - provided the original dates were accurate. If you are more interested, you should look into the standby current of the keyfob and the capacity and the self-discharge rates of the specific battery it uses.

Check out BHPian comments for more insights and information.