key fob battery
 

I needed to replace my key fob battery and was wondering how long they last, on average.

I understand that they send a continuous signal that will drain the battery even if you're not using it.

For some reason, I seem to remember replacing it once before, but not sure.

I've had two cars with fobs, 370Z and Challenger. About 2 years for both. Batteries degrade faster at higher temps, so carrying fob in pocket, leaving in sunlit car, etc, will probably mean less battery life.

Key Fob Battery
 

Here's a couple of YouTube's that deal with the science perspective of key fob batteries. (who would have thought to try this???)

https://www.youtube.com/watch?v=0Uqf71muwWc
https://www.youtube.com/watch?v=_jACSPipPSE

Can you give a little more info about the continuous signal? I never realized this. I'm surprised the coin batteries last as long as they do with this going on

If it does send a signal, I do not know the details, and I'm not sure if the fob does in fact send a continuous signal at all.

I seem to remember a Tech saying something about it, but I may have heard wrong or misunderstood. The way I took it was, for example; in order to be able to operate the car in any way, the fob must be close by, like when opening the top from outside of the car.

But, maybe the car sends a signal to the fob instead. But one way or another, such as opening the top from outside of the car, the car has to recognize the fob.

Who talks to who; that I don't know.

Im on my 2nd battery. Car is 7 years old