Charging Key
MBWorld Fanatic!
Joined: Jun 2008
Posts: 2,073
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From: San Francisco, CA
2017 E300
lol! hilarious they told you the battery is not replacement. It uses one of those watch batteries, CR, and if you pop open the back cover, and slide out the tray, you will see it easy.
MBWorld Fanatic!
Joined: Mar 2014
Posts: 3,107
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From: West Central Florida
2011 E550 P2 4M Sedan
That's pretty bad on their part. I once had service advisor change my keyfob battery in case it helped with the TPMS issue I was having. Granted the replace key battery message was on, but the two issues are clearly unrelated.
Senior Member
Joined: Jan 2009
Posts: 361
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Past 03 SL500,03 C240, 07 E350, 07 ML350, 10 ML350,11&14 E350 X2 2017 E300, 2017 C350e & 2000 S500
A sales person working for 7 years didnt know what D.O.G. is. or anything really about the cars.
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MBWorld Fanatic!
Joined: Feb 2014
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From: MA
2008 E350 4Matic, 2011 E350 4matic
I thought they did that without even charging or tell you about it. Last time I was in for service, they changed out the battery and there was no separate charge for the battery. Didn't know they had changed it out til I looked at the battery later and it was a different brand that what I had put in.
MBWorld Fanatic!
Joined: Jun 2008
Posts: 2,073
Likes: 85
From: San Francisco, CA
2017 E300
you're 14 year old key probably doesnt have smart key access, does it? For a smart key, it has to constantly send out a signal to the car wirelessly, when parked so that your doors will unlock, and also when you're driving so that the car knows the key is still inside the vehicle. Yes, they use up quite a bit of energy. In old Mercedes keys, there used to be two batteries but these new ones only fit one.
Senior Member
Joined: Jan 2015
Posts: 446
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EQE 500 4MATIC replacing EQC 4matic AMG line P
You can reduce battery usage by double clicking the locking button a red light will flash a couple of times to confirm it is in reduced function mode. The key now no longer transmits a signal thereby saving power. As soon as you press the unlock key it is fully functional again.
for those whose car is parked outside and not in a garage it is also a useful security function as it means it is not possible to intercept the key signal and then transmit to the car to steal it. There have been cases of theft in this way in th UK.
I found my c class battery lasted about a year.
for those whose car is parked outside and not in a garage it is also a useful security function as it means it is not possible to intercept the key signal and then transmit to the car to steal it. There have been cases of theft in this way in th UK.
I found my c class battery lasted about a year.
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,190
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From: MA
2008 E350 4Matic, 2011 E350 4matic
You can reduce battery usage by double clicking the locking button a red light will flash a couple of times to confirm it is in reduced function mode. The key now no longer transmits a signal thereby saving power. As soon as you press the unlock key it is fully functional again.
for those whose car is parked outside and not in a garage it is also a useful security function as it means it is not possible to intercept the key signal and then transmit to the car to steal it. There have been cases of theft in this way in th UK.
I found my c class battery lasted about a year.
for those whose car is parked outside and not in a garage it is also a useful security function as it means it is not possible to intercept the key signal and then transmit to the car to steal it. There have been cases of theft in this way in th UK.
I found my c class battery lasted about a year.
Super Member
Joined: Feb 2006
Posts: 798
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From: Bromley, UK
2017 C43 AMG Saloon
MBWorld Fanatic!
Joined: Feb 2014
Posts: 6,190
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Yeah, haven't had a car stolen in a long time. That's what insurance is for. That also defeats the whole point of keyless go. Once you shut it off, you'd have to turn it back on in order to get into the car. Which means fishing out the remote and hitting the unlock button.
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Joined: Apr 2006
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From: Dallas-Ft.Worth,TX
2016 E350 Sport
I am the only one who drives my 2016 E350. I can click the "spare" key twice and then store it in a drawer so it won't discharge. Or is it as you describe and turns itself off when in the drawer?
The fob uses a CR2025 battery. Problem is that these are special CR2025 batteries sprinkled with Benz Dust, and are available ONLY at the MB dealer for $12.50. (just kidding)
Last edited by DFWdude; Jun 20, 2018 at 05:06 PM.
Newbie
Joined: Feb 2020
Posts: 1
Likes: 0
E350 2020
Yes, newer Mercedes E350 Keyfobs Do have a rechargeable battery
CORRECTION: OMG, my dealer told me that the center console spot for the key recharged it. Others on this thread corrected me. I took my spare key apart and indeed, it is a nonrechargeable battery. Shame on me for actually believing my dealer knew how the car he sold me worked LOL. I am now checking the owners manual for several other things he said to be sure I'm not walking around with incorrect facts.
PRIOR POST (INCORRECT):
I would love to know the answer to this question as well because I put a cover on my key and it no longer fits in the little charging slot. (I added a cover because the new key is darn slippery and I've dropped it twice, it's only a matter of time before it gets busted or scratched up, the new leather cover gives it plenty of grip and provides protection).
It would also be nice to know if this keyfob charger is simply using the same QI charger that's right next to the keyfob charing area. In other words, can I simply put the key in the mobile phone charging area, and will that also charge the key? Or, can I (every now and then) put the key on a standard QI charger that I use for my phone. The alternative of taking the key out of the leather cover and charging it every now and then seems a bit inconvenient.
PRIOR POST (INCORRECT):
I would love to know the answer to this question as well because I put a cover on my key and it no longer fits in the little charging slot. (I added a cover because the new key is darn slippery and I've dropped it twice, it's only a matter of time before it gets busted or scratched up, the new leather cover gives it plenty of grip and provides protection).
It would also be nice to know if this keyfob charger is simply using the same QI charger that's right next to the keyfob charing area. In other words, can I simply put the key in the mobile phone charging area, and will that also charge the key? Or, can I (every now and then) put the key on a standard QI charger that I use for my phone. The alternative of taking the key out of the leather cover and charging it every now and then seems a bit inconvenient.
Last edited by PeterSD; Feb 24, 2020 at 12:12 PM. Reason: corrected false information from dealer
Super Member
Joined: Nov 2017
Posts: 669
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From: Hermosa Beach, California
2018 E400 Coupe
[QUOTE=PeterSD;7989885]CORRECTION: OMG, my dealer told me that the center console spot for the key recharged it. Others on this thread corrected me. I took my spare key apart and indeed, it is a nonrechargeable battery. Shame on me for actually believing my dealer knew how the car he sold me worked LOL. I am now checking the owners manual for several other things he said to be sure I'm not walking around with incorrect facts.
Don't listen to the salesmen at the dealership — in my experience they're a treasure trove of wrong. Rely on the manual, which is free to download.
Don't listen to the salesmen at the dealership — in my experience they're a treasure trove of wrong. Rely on the manual, which is free to download.
