My NX is new since end July 2025.
And it seems that the battery in the card is already dead. The service department told me that the battery was only about three months, but the cost of the battery is 20 something dollars, but that would not normally be covered under warranty or under the service contract I bought. But they would do it for me this time as a favor….. because the batteries are consumable item. Well, so is everything else under the service but that’s another story. So if you go by what they say, but a three month service life, that means an owner’s out-of-pocket cost would be about $100 a year to service the card and keep it working that. Does that make any sense? What is the battery model? Is this something that one can buy themselves at CVS or Home Depot?

 

CR2412
We both use the wallet card in our NX and RX and never had one go dead. I change them once a year. $6 on Amazon.

 

I bought 4 batteries for $22 CAD from Amazon. It typically last about one year. But this depends on your usage.

 

Just as an FYI, wear and tear items are typically not covered unless explicitly stated in a maintenance plan. So that's typically things like wiper blades, washer fluid, coolant, brake fluid, brake pads, rotors, and key fob batteries too.

 

My ‘25 NX450 smart key card lasted 10months with daily usage. CR2412 3V - $26 for Panasonic 5 pk - matched original. Easy to replace.

 

On average I would say about 10-12 months of life for all batteries in the fobs or cards that see regular use. I've gone through 2 on my '22. I don't drive that much and when I'm not using the car I put my primary fob into a faraday pouch so it goes to sleep and doesn't consume the battery. With my last recent replacement I put a note into my phone to record the date so I can review when it goes again, how long it's lasting. My other fob and my key card sit in a separate faraday pouch and so far they're both still on the original batteries.

 

The manual says the key card battery is good for "about 1 year" and the regular fob battery is good for "1 to 2 years". I got almost 18 mths out of my key card battery and my first fob battery lasted almost 2 years. My second fob (which is 8 mths younger than my first fob, due to the key fob shortage) is still on the original battery so a little more than 2 yrs so far, although it rarely gets used. I just get whatever Amazon battery replacement looks best for cheap, they might not last quite as long but they are so cheap and so easy to replace I won't mind if I have to do them a bit more frequently.

 

If you want a good battery that lasts long get the ones that are from Swiss or Japan.

 

I second this. I repair watches and my go to supplier for quality batteries is Renata - a Swiss company.

 

Has anyone tried to lay the cardkey on the button to start the car when the battery was dead or removed? I'm wondering if it will allow you to start the car the same as the FOB does when dead.

I would try this myself but I don't own a cardkey as I bought our NX as a CPO with just 2 FOBs.

 

The wallet card does work just like the key fob if the wallet card battery is dead by holding it right against the start button with the brake pedal down. Can experiment by taking out the battery to the wallet card.

 

I can confirm that it works like a keyfob. When the battery is low or dead you can put it against the start button to start the car. Use the key to open the door manual. But the battery of the key card should last 1 year if you have good quality batteries.

 

Thanks Guys, "Likes" to you both!

 

I just replaced mine. CR2412 Panasonic is what I used. Works fine. I believe it was $8 or $9.