Key FOB battery life

[Levenkay]

Of the two key fobs that the Leaf came with, I sadly only use one; the other sits in a drawer "for emergencies". But is that fob periodically pinging out its ID as if it were in use? Should the battery be removed from a disused fob?

 

[Herm]

Of the two key fobs that the Leaf came with, I sadly only use one; the other sits in a drawer "for emergencies". But is that fob periodically pinging out its ID as if it were in use? Should the battery be removed from a disused fob?

Probably a good idea, at least it would prevent damage from a leaking battery.

 

[mksE55]

most of these have a shelf life of like 3 -5 years. so not much to worry about for a while.

 

[TomT]

It's a Lithium battery inside with a shelf life of better than 10 years. Until a button is pressed, or to a lesser extent when it is within three feet of the car, there is miniscule current draw and it does nothing so I'd not sweat it.

Of the two key fobs that the Leaf came with, I sadly only use one; the other sits in a drawer "for emergencies". But is that fob periodically pinging out its ID as if it were in use? Should the battery be removed from a disused fob?

 

[keydiver]

I have only had to replace the battery in my Prius Smart Key one time in almost 6 years, with daily use. I think my wife's key is still on the original battery! If it works like a Prius Smart Key, as long as it is more than 10-20 feet from the car it shouldn't drain the battery.

 

[Herm]

It's a Lithium battery inside with a shelf life of better than 10 years. Until a button is pressed there is miniscule current draw and it does nothing so I'd not sweat it.

These button batteries never leak?

 

[TomT]

Unless they were physically destroyed, I've never personally seen a lithium button battery leak, no.

It's a Lithium battery inside with a shelf life of better than 10 years. Until a button is pressed or it is within three feet of the car there is miniscule current draw and it does nothing so I'd not sweat it.

These button batteries never leak?

 

[davewill]

These button batteries never leak?

I don't know about "never", but their main feature for these applications are their small size and a long shelf life. They can sit unused for years, and still be good.

 

[Levenkay]

It's a Lithium battery inside with a shelf life of better than 10 years. Until a button is pressed there is miniscule current draw and it does nothing so I'd not sweat it.

So the power that the keyless entry system uses to scan for the fob's proximity comes from the car?

I was kind of worried that there would be a periodic drain on the fob's battery, which (since I almost never use the fob's pushbuttons) would have the "emergency spare" failing at roughly the same time as the "daily use" fob.

 

[TomT]

It's a transponder system but the majority of the power is consumed by the car side of the system. The fob transponder is very low power and if the fob is further away than about 1 meter from the car, it will sit in a near dormant sate with very low power draw. Even in or near the car, the draw is extremely low. But yes, there is a way for the car to power the fob should the battery die completely via a loop near the car's power button.

It's a Lithium battery inside with a shelf life of better than 10 years. Until a button is pressed, or to a lesser extent when it is within three feet of the car, there is miniscule current draw and it does nothing so I'd not sweat it.

So the power that the keyless entry system uses to scan for the fob's proximity comes from the car?
I was kind of worried that there would be a periodic drain on the fob's battery, which (since I almost never use the fob's pushbuttons) would have the "emergency spare" failing at roughly the same time as the "daily use" fob.

 

[Coffee_Slurry]

It's not entirely dormant -- it has to run a receiver non-stop. Or rather, it has to wake up often and listen (poll) for the car's transponder.

The "smart key" kind has to be alert 24/7 in case you approach the car.
The pushbutton kind can be completely unpowered when you're not pushing a button.

In my experience, the Toyota transponder went three years on a CR1632 battery, which isn't one of the common ones.

 

[TomT]

Hence my comment about being "near dormant..." The one for our Acura went 7 years before needing a new CR2025 battery...

It's not entirely dormant -- it has to run a receiver non-stop. Or rather, it has to wake up often and listen (poll) for the car's transponder.

 

[Deleted member 3147]

My 2007 Prius fob used a CR2032 and the one I used lasted over 4 years. The spare seemed to still be good at that point.

 

[fotajoye]

Just replaced my FOB battery, found the second FOB battery was also bad and I noted there was a dab of liquid under both batteries which indicates electrolyte leakage.

Cleaned out the liquid in both FOBs in case it could cause corrosion. Bought two batteries, CR2032, replaced the battery in one FOB and tape the second battery to the outside of the spare FOB, I'm going to assume the FOBs are always on and I will replace the battery when I need to use the spare. My FOB works fine on the CR2032 Lithium battery and BTW the shelf life of an unused lithium battery is said to be about 10 years.

 

[DaveinOlyWA]

I have only had to replace the battery in my Prius Smart Key one time in almost 6 years, with daily use. I think my wife's key is still on the original battery! If it works like a Prius Smart Key, as long as it is more than 10-20 feet from the car it shouldn't drain the battery.

you have smart key? if you did, then you are probably near a record for longevity. in my Priuses the batteries (all with smart key) lasted just about the same amount of time as my LEAF keys...2-3 years

keep in mind, on both the 2006 and 2010, only one key was used most of the time (at least 80% of the time) and the other key was never in the vicinity (at least 30 feet away) otherwise but did not matter. just like the LEAF keys, both batteries died within a few months (the LEAF keys died literally within days of each other...well as close as you can determine since the keys fade away) of each other.

i think the "key" factor (pun intended) is how much of that shelf life was used BEFORE it became part of the LEAF system

 

[HighDesertDriver]

Paul is an EV advocate, Leaf owner, and Leaf salesman at a downtown LA Nissan dealer. He sometimes emails info like this to those with whom he has had contact over the years. Thought it might be of interest to others with FOB battery questions.

Paul Scott
Dec 10, 2013
9 days ago

All,

Last week, one of my first customers from the 2011 model year called to say her car was not readily detecting the key fob. She had to make several tries to start her car. I had not heard of this problem before and told her to bring it in. Turns out, the battery was getting weak and would only detect the fob if it was brought close to the "START" button. We replaced her battery and the problem was solved.

Two days later, I was contacted by another early customer with the same problem. I was able to tell her the solution. Since then, three more customers have contacted me with the same issue. Five customers with the same problem inside of one week is a lot, so I'm passing this on to corporate in hopes they will send out a bulletin of some sort to all first year LEAF drivers.

Any of you with this problem are welcome to bring your car in for a replacement battery, or you can open the fob by prying it along the seam and replace the battery yourself. The batteries are easy to find at any store that carries small batteries.

Paul

 

[mwalsh]

^ I don't know how these owners are missing the low fob battery warning. I really don't.

 

[TomT]

+1

^ I don't know how these owners are missing the low fob battery warning. I really don't.

 

[HighDesertDriver]

As foreign as it my sound to those of us in the hands-on crowd, there are huge numbers of owners, both ICE and BEV, who never think about looking under the hood or in the owner's manual. Their first response is to call their salesman, dealer, or local shop. Unfortunately, some will be advised to get a transmission overhaul, and some will be invited in for a free coin battery swap while sipping complimentary coffee. There is no fault in relying on the salesman or dealer, but like with diamonds, know your jeweler.

 

[TimLee]

... My FOB works fine on the CR2032 Lithium battery ...

You got lucky. :shock:
Depending on the battery thickness manufacturing tolerance, and the fob manufacturing tolerance, not all CR2032s will work. Safer to go with the correct CR2025.