northcoast

Anyone have to replace the battery on their key fob yet? I'm getting a warning message to replace (on the screen between the speedo and tach).
Surprised that it has to be replaced in < 2 years (I have a 2017)...wondering if it is unusual or not.
Thanks!

mikbar2

We have to replace ours every 18 to 24 months to include the spare. Don't leave the fob in the car when you get out with a low battery. Wife did this and it locked her out.

northcoast

Just found this:
Worked like a charm -- just have to go buy a battery now.

decorily

Replaced mine at about 18mts.
I think the keyless go causes an extra drain on battery.

Sigp232

Tylbran

For both my 2014 SLK and 2016 E63 wagon the battery was changed with every service (A & B) (1/year). I presume that the same will be true for my 2018 GLC43.

mikbar2

waylo

I also was somewhat surprised myself they need them changed as soon as they did. Even our spare one which sat in a drawer needed it redone sooner than I'd have thought. ~1.5 years in.

fabbrisd1

So you know - earlier recommendation was to change with genuine Maxell CR2025 from Amazon as a better battery - but unfortunately China now counterfeited that battery/packaging so the Maxell recommendation is dead.

ALWAYS replace batteries in BOTH key Fob's at the same time - if the battery in the Fob you are regularly using is going - your other not-used-as-much Fob battery is going too.

Almost all the CR2025 batteries you buy at the big box retailer - drugf store - Walmart- Lowe's etc - regardless of brand - are "sh*t".

The best CR2025 battery out there now is the authentic Panasonic brand CR2025 - ONLY in this correct/authentic blaster card packaging shown in this Amazon 20-for-$8 - or eBay listing 4-for-$2.30 - shown below - both free shipping. Note with 5yr shelf life you have a lifetime supply.

Frankly - the MB blister Panasonic CR2025 they have as dealer item - I strongly suspect MANY of those dealer batteries are China counterfeits as well - as they do not last as long as the GENUINE Panasonic sold on this correct red card:


https://www.ebay.com/itm/FRESHLY-NEW...kAAOSwNnRYk1Ye

Philamg

If you press the shut button on key fob twice after closing the key is disabled and as well as saving the batteries it stops it being cloned.

jrc_slc43

Ok similar question.. my wife's GLC300 started with the "change key battery" warning message. So no big deal.. I changed it. But the message won't go away. So why the message? I pulled the start button cover and put the key in the slot thinking maybe it needed to re-register it or something.. but nope, the message comes back after each start. Should I take the car to the dealer?

VancityGLC

Maybe your wife carries her key at the same time as well and that one needs a battery replacement? If not then probably check with the dealer.

waylo

Where did your replacement battery come from? Brand new?

Truckeralex

fabbrisd1

Genuine Panasonic CR2025 (in red pack) last longer than the Panasonic batteries from MB ... like WAY longer.

For less than $6 - at least 5yrs supply...

Chrisk03

Do you mean hit the "Lock" button twice after closing all doors, etc.? Just want to be clear.

If so, this is similar to other makes with a keyless go type system, where if you DON'T "lock" the vehicle after exiting, the communications stay active with phone (Bluetooth), keys, and whatever, and can drain keyfob(s) and car battery more quickly, over time.

fabbrisd1

"Short" battery life on Mercedes new car keys is just due to one thing... "aged batteries".... Mercedes buys a ton of Panasonic CR2025 and as far as I can tell they sit in parts inventory somewhere way to dang long.

I can't believe the circle of b*ll**** that has comes up from Service Advisers on this ....

I had my guys switch to "Fresh & Genuine" Panasonic CR2025 (red pack) - and they last about twice as long at least over MB/Panasonic... we used to use Maxell CR2025 but now over 90% of those Maxell are China counterfeit ... so we 2nd sourced Red-Pac CR2025

waylo

This question was not, where does one get batteries from generally? Rather, specifically, where did the poster get his/her used battery from, in that specific case. The other fob? A new package somewhere? The bottom of the kitchen drawer that contains all old miscellaneous items?

Years ago, I tried swapping the battery from the 'unused' fob when I first got this error. Unbeknownst to me (but now enlightened from this forum), because I had not double-pressed lock, the battery was continuously draining in that unused fob, and hence that battery was just as drained as the one being used primarily.

Jetfuture

You know you have a great car when you complain about having to replace a FOB battery every 2 years. Sheesh

ajmtbm

mine was replaced in a little over a year.
seemed quick compared to other vehicles, thankfully the batteries are very inexpensive