berman2921

Batteries in both of my key fobs die very quickly: within a month usually.

Does it happen to anyone else? What brand of batteries do you use?

I assume they are not covered by warranty.

Thanks in advance

sleeperZ96BT

You have keyless go, I assume?


If so - do a quick search, you'll see the usual suspects. Best solution I have used is take your push button start out. We usually get 6 months per battery though, not one month.

blegthbloo

Apparently if you don't use Panasonic brand in the fobs, they die very quickly. Must have a partnership with them to only work with their batteries... dunno. The one in my fob now is Panasonic and it works as it should, and it's been there over a year now.

JSch

^^ As the above comments, Panasonic is the preferred brand and there is a thread on batteries.

Also, make sure the key fobs are not too close to the car. I will drain the batteries as well.

jahquan3

I've been using Energizer and I get 6 months out of each battery.

berman2921

Thank you guys. Will try energizer or panasonic

sleeperZ96BT

Same here, but I may try Panasonic given the comments.

belarus27

ive had a Renata battery for a while
satisfied

thenew3

I was told a couple weeks ago by a tech at the local MB dealer that there's a service bulletin on this issue. Apparently there was a big batch of keys made with a flaw that causes high battery drain. He suggested I ask the service advisor to test/check out my key and get it replaced.

I found that even after the change key battery warning comes on , my key continues to work for another 6 to 8 months without changing the battery. So it seems the battery isn't really low, just whatever system they use to detect a low battery state is buggy and reporting way too early.

I've also started using a slightly thicker battery. CR2032 which still fits and gives me significantly longer life (1+ years).

blueshound

I just replaced one of my FOB's batteries, I have something to confess. Remember to take off the little plastic tape on the bottom of the battery. I thought my FOB was bad because it wouldn't work after changing the battery. Took me a couple of tries to figure out it had a protective tape on the bottom. DOH

cetialpha5

Just got my car back from the dealer. Told them up update Comand and keyless go. Not sure if they did the latter, but they changed the battery in the keyfob and I just looked and it was a Panasonic. I've tried several different types, Durcell, Energizer, Sony, but they don't seem to last very long. Guess I've give the Panasonic a shot, could be where the batteries are made, some of them were made in either China or Japan. Panasonic seems to be made in Indonesia. Or the eBay ones I'm getting are fakes from some cheap knock off factory.

blegthbloo

The ones you're getting are probably used, and to "charge" them they have the sweatshop orphans lick them repeatedly while rubbing their feet on the carpet.

cetialpha5

Possibly, they're in the factory packaging instead of bulk like some really cheap places. But they're good about making fake factory packaging. Maybe they cut back on the lithium in the batteries. Voltage is good, usually 3.35 volts, but when you get the warning, they're down to 3.1 or less. Oh well, can't expect too much when they're only 50 cents each.

The G Man

I agree, you get what you paid for. I try not to buy batteries that seem like too much of a bargain.

kbob999

From the Service Bulletin Thread:

LI80.35-P-063677 - All models Keyless-Go DAS4 (2007 >) “Replace battery in transmitter key” reappears in instrument cluster within a few days after replacement, update KG control unit software/perform SCN coding. FYI if key enters passive mode resulting in no feedback from key during KG engine start key can be reset by removing battery.

cetialpha5

That's why I had the dealer do a Comand update and keyless go the last time I was there. That was only a few weeks ago, we'll see how long the Panasonic battery they put in lasts. The ones I got were name brand, but you can get generic batteries for about 12 cents each if you get it in volume.

berman2921

Update: just took the car to MB and was told E class should use CR2032. They even inserted 2 new batteries

cetialpha5

What year is your car? The 2011 uses one CR2025, but you can fit a CR2032 in there. My 2008 used 2 CR2025, but it used a clip to hold it in and it won't fit if you use 2 CR2032's.

berman2921

2016, thank you

berman2921

They also told me that the keys should not be stored at home close to each other or cell phone. Putting battery into the sleep node doesn't matter according to the advisor. I never had a problem with the key fobs from Lexus or BMW - the batteries lasted at least 1.5 years

Zavato

Just replaced my gob batteries. Not because there was any issue but simply because I've had my car a year now. Bought some Panasonic batteries on eBay, and it seems I'm good to go.

fintail

My local dealer replaces them for free. I seem to get about a year out of them maybe just a little less.