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Key Fob Battery Life....

Key Fob Battery Life....

Woke up this morning to find that my MX would not respond to either key fob. I had to use the mobile app to unlock the car and start. Called service and was told that batteries for BOTH key fobs had to be replaced? Something about a known problem with the key fobs. Sounded a bit off that both would go kaput at about the same time. Took my MS over to the SC and they replaced both batteries (they actually wanted me to drive the MX over using my mobile app..LOL...they seemed to think it was something with the car). Got home and Voila, the car worked perfectly. My guess is what is happening is that unless the key fob is out of range, it is still in communication with the MX (this was the problem with the driver side door opening and closing, it was in contact with both key fobs even though the second was in another room) causing battery drain. I suggest that when parked, both key fobs be located as far from the MX as possible or placed in a metal box (Faraday cage) to eliminate the RF link.

ernie | 2 April, 2016

Buy a couple 5 packs of batteries on Amazon. Keep some in your glove box.

loganboyd | 3 April, 2016

It's rather ridiculous that you have to buy extra batteris for a key fob on a $100k car. Don't ya think?

vperl | 3 April, 2016

Maybe after five or six years

My fobs battery is going to be drained dry after waiting three years.

Do not expect full fob batteries on the Model 3

keith | 3 April, 2016

There weeks in and I woke yesterday to find that neither of my keys would work. One of them never worked. I am unlocking and driving the car with the mobile app. What a pain in the butt. I will be at Service Center in Burlingame first thing tomorrow and will expect them to rectify on the spot.
Several other minor issues to get resolved: driver side door sometimes opens fully, sometimes only a tad; auto garage door works irregularly; my driveway has a slight slope and so no passengers doors will open.

paradis | 3 April, 2016

I have mine about 7 weeks & 2,000 miles and the fobs are both still fine. The best deal I could find for batteries was this on Amazon. I keep 2 in the car and the rest at home.

http://www.amazon.com/Pack-Panasonic-CR2354-lithium-BATTERIES/dp/B00KFSV...

vperl | 3 April, 2016

CR 2354
Panasonic

evlnte | 4 April, 2016

At first, I was going to respond with a snarky remark about buying extra batteries (which someone already said) but I'm holding a Bluetooth, USB recharged AppleTV remote in my hand. What about that Tesla? A $100k car deserves a convenient FOB and a stellar App. I should be able to open my car by now with my finger print on my phone!

vperl | 4 April, 2016

Put your reservation down for the iApple car.

Whoops, smoke

jjgunn | 21 November, 2018

Old thread....was wondering how long battery lasts (ball park figure?) In the Fobs?

I ask because I had my key in the center console cup holder like usual & got the msg "key not in car" so I grabbed the fob gave a click & it went away.

Just wondering everyone's experience with the Fob batteries. Thanks

lilbean | 21 November, 2018

The batteries last much longer when you keep the fob away from the car so they aren’t constantly communicating. I know mine last over a year. They last longer but I don’t know how long because the service center changes them at the annual service.

Passion2Fly | 21 November, 2018

Make sure that the replacement batteries are good quality! Mine got replaced by the SC and one key-fob failed after 3 weeks... Measure the battery voltage out of the box and make sure it's above 3 Volts...

My working key fob shows a voltage of 3.02V and the failed one only shows 2.92V...

jjgunn | 21 November, 2018

Thanks @lilbean & @Passion.

Passion you using a voltmeter? Or is there an option I'm missing to see the fob voltage?

Passion2Fly | 21 November, 2018

I’m using a high accuracy voltmeter, yes. The problem with batteries is that the voltage without the load is not very telling... you need to load the battery up to see a significant voltage drop (2.75V for 3V batteries is typical when the battery is low). However, an unloaded voltage below 3V is usually not a good sign...

adehuiwang | 8 January, 2019

Mine failed today... the original battery last just over two years, two years and two weeks, to be exact.

kishorekv | 12 January, 2019

Three weeks old MX, and the key fobs are hit and miss in getting recognized by the car even when inside. Time to replace the batteries.

robbetts5 | 12 January, 2019

Just had my fob replaced. I think it had an internal short. August delivery; the battery went dead in December. I replaced the battery and it was dead in one hour. Put in another that was tested at over 3 volts, down to 2 volts in 30 minutes. SC verified it was killing batteries and replaced it. I hadn’t dropped it. I don’t know why it went bad. But the SC was good about giving me another after they verified it was causing the problem.

georgehawley.fl.us | 13 January, 2019

My fob keys have never failed to work but I got a weak battery alert from the car after about 2 1/2 years so I replaced the cell. The fob key still worked and the alert didn't go away. I thought it might be a shelf life issue because the replacement cell resided in the glove box for two years. I bought fresh batteries from Amazon. The fob key still worked. I had an appointment at the SC for another minor matter and asked them to check the fob key. They couldn't get the alert to go away until they updated my software to v9. The fob key still works. Go figure.