Key Batteries, Again ...
Thread Starter
MBWorld Fanatic!
Joined: Aug 2017
Posts: 1,697
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2019 S560, 2015 Honda Civic Hybrid
Key Batteries, Again ...
How long should key batteries last? The one I just put in a month or so ago is giving me the 'Replace Battery' and 'Key Not Detected' messages again. The ones in our Honda keys last for a year or more.
MBWorld Fanatic!
Joined: Nov 2015
Posts: 1,694
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From: Newcastle, WA
2019 S63 4Matic+, 2018 E400 Cabrio, wardens car.
These coin type batteries can sit on the shelf for a while and that can cause a shortened lifespan. I just purchased a Duracell blister pack of 20 of these from Costco for around 8 bucks and they seem to work really well so far.
Super Member
Joined: Nov 2021
Posts: 893
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From: Hong Kong, China
2021 S450 4Matic
I think MB recommends changing the battery on a yearly basis, regardless if the message pops up or not.
But I am lazy and often do not change until I get the warning.
In addition to the possibility that the CR2025s having been sitting in the store too long, another thing is the fob sends out signal when it detects its moving around. So, if the key is in motion most of the time of the day, it might further reduce its life span?
But I am lazy and often do not change until I get the warning.
In addition to the possibility that the CR2025s having been sitting in the store too long, another thing is the fob sends out signal when it detects its moving around. So, if the key is in motion most of the time of the day, it might further reduce its life span?
Out Of Control!!
Joined: Nov 2018
Posts: 11,463
Likes: 5,354
From: San Francisco Bay Area
2019 C63CS
You have the old key fob w/o the motion sensor, so it basically constantly sends out a signal and listens for a ping back from the car. Even so it should last more than a few months. You can preserve the battery by double clicking the lock button to turn it off. FWIW, I just changed the battery after almost 4 years in my newer fob with the motion sensor. It sits on my desk most of the time, so it's dormant until I pick it up and move it around.
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Member
Joined: May 2021
Posts: 228
Likes: 126
From: Zürich, Switzerland
S560 Long 4Matic (DE) MY 2018
After I put my key in the washing machine by accident, I dried it properly and it started working again. However the remote also started going through batteries like crazy, one every two weeks. Had to eventually have it replaced by the dealership.
Last edited by Quenthel; Apr 5, 2023 at 07:52 AM.
Thread Starter
MBWorld Fanatic!
Joined: Aug 2017
Posts: 1,697
Likes: 522
2019 S560, 2015 Honda Civic Hybrid
Briefly resurrecting this thread to say no more trouble since getting new name-brand batteries. The cheapo ten-pack I bought from Amazon must have been all bad.
I did hear from someone that a lot of batteries and products that come with batteries went bad during Covid from sitting in too long in warehouses. Anyway, nice to have my keys working reliably again.
I did hear from someone that a lot of batteries and products that come with batteries went bad during Covid from sitting in too long in warehouses. Anyway, nice to have my keys working reliably again.
Super Member
Joined: Dec 2004
Posts: 635
Likes: 68
From: Raleigh, NC
2020 S560 4Matic
What's the different message, warning light etc for the keyfob battery versus the two (?) main and auxiliary batteries (12V)? I don't want to have a heart attack because the key fob battery is bad.
And does that little key compartment actually work? I ask because I had a lock/unlock problem, had the alarm going off and car was prompting me to insert key in that area. I did but it did nothing. Problem fixed by using the keyfob to unlock car while *inside*.
I also have one of those old packs of batteries sitting at home. I'll get new ones.
And does that little key compartment actually work? I ask because I had a lock/unlock problem, had the alarm going off and car was prompting me to insert key in that area. I did but it did nothing. Problem fixed by using the keyfob to unlock car while *inside*.
I also have one of those old packs of batteries sitting at home. I'll get new ones.
Member
Joined: Feb 2007
Posts: 160
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From: Sandy Springs, GA
'15 E350, '20 S560
I started keeping the fobs in a drawer and they seem to last longer than when “free range” on the desk top which is only about 20’ from the garage. My guess is they would communicate with the car, probably hatching a conspiracy on when to break and funnel funds to the dealership.
