dukester34

how often do I need to charge my key. during the delivery I was told the battery is not replaceable. how often are you all placing the key in charger?
ty

vic viper

The battery is replaceable, key is not charging in the ashtray compartment.

joshg1001

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.

nas2344

dukester34

really no **** lol....

thefisch

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.

Mbracer26

Hahahaha

A sales person working for 7 years didnt know what D.O.G. is. or anything really about the cars.

joshg1001

If you buy the prepaid Mercedes service packages, I believe it includes key battery changes...

cetialpha5

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.

petee1997

My dealer changes the battery at no charge and gives me second battery for the spare. It's al part of the annual service.

CaptainE

joshg1001

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.

CaptainE

parkwood

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.

cetialpha5

That's too much work to save a few cents. You can get a 10 pack of Energizers for about $4 on eBay.

guhvies

Yeah but when it prevents you car from being nicked, priceless...

cetialpha5

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.

vic viper

Later versions of the FBS4 key system has an built in accelerometer that turns the keyless transmitter off when the key has been stationary for a while.

DFWdude

OK so I would like to know...

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)

PeterSD

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.

ua549

@PeterSD You are wrong! The CR2025 battery is not rechargeable. There is no keyfob charger. The keyfob slot is used as a sensor to enable the start button in case of keyfob battery failure.

The_Judge

[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.

ua549

The only time you will need to use the key slot is if the battery in the fob fails. I keep the fob in my pocket 100% of the time.

IronBallsMcGint

The dealer salesperson told me that same thing.... Shame on me for believing him.

nycebo

Damn, I was excited for all of 2 seconds.