froggy47

Had this 2015 about 1 yr & has about 4k miles (low miles - retired wife's car). About a week ago "my" fob (which I use about once a month) called for battery replacement (driver msg) so I figured hell, must have had a crap battery when I got it. Other makes last several years easy.
Yesterday my wife's fob sent the same message so I had bought a 2 pkg 2025, so I did hers.



Today she get's the message again with the brand new battery, haven't tried mine yet.

Now I'm thinking somethings messed up with the car, draining both fob batteries.

Any help?

PS it has keyless go.

Thanks!

Rainers

This happened to me also,,,,, batteries were bad. I bought another pack at a different store and was fine.

Also do not keep the fob in the parked car because if it is in range it will alway talk to the car and draining your battery

Ejbrock

Ejbrock
+1 with Raiders reply.

froggy47

Thanks, I don't keep it in the car, but fair point. I'll get some more, these were from a napa store & should have been fresh, "use by" was 03/2024



But still could be bad.

formerjeepguy

As many have stated in other threads, make sure you get the Panasonic batteries that are made in Japan. All others seem to be crap.

Also - the dealer will likely replace the batteries for free. YMMV

Don't store the key near your phone or metal. Carry it in a pocket with nothing else - no loose change and minimal keys. Big metal key fobs should also be avoided. The key is a radio transmitter and the harder it has to work, the faster the battery will drain.

ZZGlk

I have found that distance from car is vital both for draining fob battery, but also for draining the main car battery. I had trouble with my fob batteries only lasting a couple of months and also a measurable drain of 2-3 amps from the main car battery. Dealer couldn't ever solve my problem.

To troubleshoot I installed a datalogger on both car batteries and observed that overnight the main battery would drain, but when I parked the car someplace during the day it would be fine. After some troubleshooting, I suspected that the car was staying awake at night because my fob was just above the garage in the kitchen. To verify, I moved the fob to the back of the house at night and didn't see any drain.

Now, when I'm at home, I drop my key fob in a rf shielded pouch. This keeps the fob from talking to the car and keeping it awake and also has extended my fob battery life. I've now gone almost a year on the same fob battery and still going strong. I bought the pouch on Amazon for $9 and I can get in the car with the keys in the pouch and the car won't detect the fob. This also prevents someone from reading your fob and remotely unlocking your car.

AzCamel

glad you solved your problem but this applies to only the cars with the smart key aka push button

froggy47

This is very interesting. My distance from the dashboard area to the fob (where my wife "parks" her purse) is about 30 feet. In your estimation is that a distance where the fob and the "receiver" would be in constant communication? The battery did last 1 year. I would think that means there IS SUFFICIENT DISTANCE to "break" the communication, but that's just my guess.

ZZGlk

I think 30 feet should be enough to let the car sleep. A lot depends on wall construction and any metal in between. My keys were about 15 ft above the car and that was close enough to keep it talking and not go to sleep.

I was going to borrow a spectrum analyzer and check out the frequencies and distances, but my shielded pouch keeps signals attenuated everywhere, even in the car.

fabbrisd1

All this discussion is "interesting" - but the weak link in fob battery life is quite simply CHEAP SH*T INDONESIA or CHINA batteries... MB/Panasonic is made in Indonesia.. Energizer China or Indonesia.. and enough China knock-off branded batteries in the market to fill the Titanic..

To start ... less than $3 for 5pcs from Amazon genuine Maxell CR2025 ONLY in holgram packkage:

https://www.amazon.com/Maxell-Lithiu...=maxell+cr2025

Since we changedover at our dealership ... "dead" fob batteries dropped by 80%..

Keep the beat !

ZZGlk

You are correct. Battery choice is the biggest factor. I read your earlier post about using Maxell batteries when I noticed short life from my fob and they did give me more life, but I still only got two months out of them so started looking for other causes. I'm interested to see how much life I can get out of Maxell batteries when the car and fob aren't talking all the time.

glennhl

Froggy, great video, as usual! I saw the pocket knife and I was ready to tell you to use the key to open the FOB, but you already knew that....

Ejbrock

Ejbrock
ZZGLK great write up on the fob. Today I bought a RF Shielded Pouch! I believe that you are spot on with your findings