Key fob eating batteries

[JBroadwell]

Good afternoon:

key fob battery replacement January 2020, needed one mid June, again four days ago and it’s reporting low battery today. Thoughts?

 

[joegr]

Did you see this thread?
Perhaps Genesis could ... for every new car owner

Try keeping the fob away from your phone?

 

[Don88]

Good afternoon:

key fob battery replacement January 2020, needed one mid June, again four days ago and it’s reporting low battery today. Thoughts?

JB, I wonder if you have a weak spring in the fob and it is accidently being depressed thus activating the circuit in the fob, using some of the battery reserve? Because the fob is a transmitter, seems the only time it would use power is when it was on, a key depressed?
Just an old timer's guess???

 

[joegr]

...Because the fob is a transmitter, seems the only time it would use power is when it was on, a key depressed?
Just an old timer's guess???

No, it's more complicated than that. It is also a receiver. It is always listening for the car to be nearby. If it thinks that it is, then it wakes up and transmits to the car to try and do an encrypted exchange to authenticate. This is why you can press the button on the door handle and unlock the car (if you have the smart key on you).

 

[DrKK]

Right, as @joegr says, if the key fob is near enough to the car that the car is communicating with it for extended periods of time, it would drain the battery potentially. Is it near the car?

Also, a lot of the coin cell batteries when sourced from lower priced vendors are already quite old and do not hold the expected amount of capacity.

 

[JBroadwell]

Right, as @joegr says, if the key fob is near enough to the car that the car is communicating with it for extended periods of time, it would drain the battery potentially. Is it near the car?

Also, a lot of the coin cell batteries when sourced from lower priced vendors are already quite old and do not hold the expected amount of capacity.

I get that. Second replacement was at my daughter’s totally different batch.

 

[WPB]

Somethings wrong with the fob. I took delivery of my car in December 2017. Both fobs still working fine with no battery replacements yet.

 

[TinsleyC]

As Joegr said, check that thread he referred to. Two points came out of the thread -

- Do you typically keep your fob close to the car, like on the other side of a wall, only a few feet away? If so, move the fob father away, or use a Faraday container.

- Do you typically keep your fob close to your cell phone? If so, separate them or use a Faraday container.

 

[JBroadwell]

Thanks for the input. I don’t believe location or proximity to cell phone is an issue. Nothing has changed in the 2 1/2 years I’ve owned the car except this new onset issue.

 

[TinsleyC]

I'd blame the fob, then. Does the other fob eat batteries, too?

There's always the chance you got your hands on a string of bad batteries. These flat batteries are often bought in a blister pack and sit in a drawer for years.

Amazon just had a sale on a six pack of Duracell 2032's for under $4, but I just checked and it's sold out.

 

[JBroadwell]

I'd blame the fob, then. Does the other fob eat batteries, too?

There's always the chance you got your hands on a string of bad batteries. These flat batteries are often bought in a blister pack and sit in a drawer for years.

Amazon just had a sale on a six pack of Duracell 2032's for under $4, but I just checked and it's sold out.

As in original post, batteries from two different batches, even the province where they were purchased. Other fob seems okay.

 

[GarnetTy1473]

Are you having the batteries tested before you replace them? New, they will test 3.0-3.1 volts and about 2.8-2.9 volts under a load. The low fob battery light starts coming on when they are testing about 2.5-2.6 volts under a load. Every once in awhile, the low battery light will come on when the under load volts are lower.