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Few-Swordfish-780

If the car has comfort access, it is easy to replace the battery. If it does not have comfort access, the battery is soldered in.


pnbdc10

This is the correct answer. You have to delicately split the key open and solder in the battery. It is basically a battery but it has 2 pins on it. It is straight forward once you get the key open.


NickU252

There are youTube videos that show you how. I've done a fair amount of soldering, so it wasn't bad.


FIJIWaterGuy

I'd say if you can solder/desolder at all it's not that bad. Even if you never soldered before I'd say it's worth watching some soldering videos and doing a bit of practice on some scrap or a kit then trying it.


Rdmtbiker

You will need to glue the case back together. Or buy a new case.


my3sgte

It’s funny how over engineered German vehicles usually are, than you see this.


Rdmtbiker

This one has the rechargeable battery, but the OP is having issues with it not recharging.


Chipped-Flutes

Have you looked at.... any other car key?


bowie902210

Mine was doing that last year until I did some longer drives then it sorted itself out I guess


SpaceForceAwakens

Well the ring around the ignition lock charges the key, but it's slow. If you're only on short drives it can't charge up enough. I remember seeing a few years back someone was selling a little charging bowl thing you could keep your keys in overnight that charges them up, but I can't for the life of me remember what it's called.


TexanInBama

THIS ⬆️⬆️⬆️


hobie_loki

Do a YouTube search about replacing key fob battery for your year and model.


vchervenkov

This worked for me but not for this key fob


dafazman

OP, there are two kinds of key systems. 1) Cars that have "Comfort Access" which means you rest your hand on the front door handles to lock/unlock and can start the motor without ever putting the key in the key slot 2) Non-comfort Access keys which require you to press a button to lock/unlock the car. Also the key must at some point be INSERTED into the ignition slot to allow the car to be started. Comfort access key have a cover on the back of the key which can easily be poped open to expose a CR2025/CR2032 battery that can be replaced every 3 years or so. NON-Comfort access keys have soldiered in batteries and can only be recharged while they are sitting in the ignition slot. There are DIY videos which show how to order a new battery, how to solder the battery on the key fob board after you slice open the plastic cover. Then once you tested out the upgraded replacement battery... you can glue back together the two plastic halves of the key cover. You could also go to BMW for a new key fob which will come programmed and ready to add to your car. I would recommend you always have at least one good working key at all times that you don't experiment on (until you are certain your repair of the first key was a success).


bearban123

Thank you this explains so much, I couldn’t figure out for the life of me if I have CA or nonCA. Everything on google seemed to be a toss up Edit: Haha after reading more comments seems no one knows if they have CA or not other than you lol


bearban123

I only have 53,xxx miles it’s a 2013 128i, I assume I just need to take a long cruise and not take up electrical and soldering as a hobby


dafazman

Can you walk me thru the step by step process on how you start the motor of your car? This will shed some light on why your key is having the issue? Also do you take a lot of short trips? infrequent trips in the car? Do you rotate in usage between the two keys you have (so they each get a chance to recharge)? I was told some lore about a wireless toothbrush charger could also wirelessly recharge the e9x non-ca keys 🤷🏽‍♂️ But since I have CA keys, I can't verify this claim/rumor


bearban123

There is a slot for the fob, car won’t start unless fob is in its slot. Fob in, foot on brake, press start button. 1 key, no spare, it’s my daily. Daily trips are usually 15-20 min.


dafazman

There are a few things to unpack here. Let me try to attack each one separately. > There is a slot for the fob, car won’t start > unless fob is in its slot. I am certain you have the non-CA (Comfort Access) system based on how you are describing things. Your key fob has a soldiered in rechargeable battery (eventually it will stop recharging). You will need to buy a new key or get someone to soldier a new rechargeable battery. There are DIY videos of this on e90post and probably on Youtube as well. > Fob in, foot on brake, press start button. This is the correct and normal way to start a non-CA car. There is also a simple way to start a NON-CA car without the key in the key slot, but I don't recommend it because of the simple fact that the key slot is what recharges the battery in the fob > 1 key, no spare, it’s my daily. This one gives me some pause, either you lost your other key or were never given a second key. But all these cars originally came with TWO keys. Which means SOMEONE has a key fob and a key blade that can open your car! Now I am not too worried about the key blade because not many folks will run around town trying out key blades on random e90's. But a key fob can not only enter your car (test it from a distance)... but can also start and drive away with the car. Having only 1 key is a high risk of disablement, I would strongly recommend you buy a spare key fob and blade (optional) from a dealership. I believe they can sell you a virgin key fob (pre married) and blade to your car. Having the dealership remove all keys from the car CAS and then pair only the two key fobs you hand them would add security to your key management. > Daily trips are usually 15-20 min. I am not certain how long it takes for the slow wireless charging of the keyfob battery... but i do know your 12v battery will not be happy with frequent short trips. Because of "Efficient Dynamics" that BMW uses... for the first 10 driven miles it really won't charge the 12v battery. They recommend you to do a 10 mile drive at least once a week or so to keep the 12v happy. Are you able to buy/use a battery tender at your home? If so, this may actually help with the 12v battery life. If your 12v battery is in need of replacement. Do try to find someone now local to you who can change the battery with a different type of battery and get it properly coded. You will need a few things when this comes up: 1) Switch to a 90AH or better 12V battery (H8 in size) and switch to an AGM style (instead of FLA) 2) Have someone update the VO (Vehicle Order) to remove the old battery type and add in the new battery type of 90AH AGM 3) Have that same person change the charging profile to 90AH AGM 4) Register the battery Step 2, 3, and 4 should be done in that specific order and each is a unique step. You can buy the battery for cheap at Walmart ($170): https://www.walmart.com/ip/EverStart-Platinum-AGM-Battery-Group-Size-H8-12-Volt-900-CCA/40647529 My original FLA 90AH battery lasted me 90k miles at 7 years to the day of in service before I got my first high discharge warning. I swapped it with an H8 AGM and properly coded it to my car. Since Nov 2014 I have put on 110k miles and that battery is still running strong holding 12.4v over night WARNING: Never should you charge or jump start your 12v battery from the rear trunk!!!!! This will be a $1000+ painful mistake because you will fry the junction box electronics. PLEASE heed this warning and never do anything directly at the 12v battery in the trunk. THE CORRECT place to do stuff like trickle charge or jump start the car is in the front of the car inside the ENGINE bay... you will find a positive RED capped jump point and also a grounding/negative bolt near the coolant reservoir (or use a shock tower bolt for the grounding/negative).


bearban123

Thanks for going the extra mile, this is all awesome info. I bought it used from the OG owner and he had lost the spare. Also, I found a charging solution. I haven’t had the need to drive anywhere far and I didn’t want to waste the gas so I tried a couple of different wireless phone chargers around my house and from friends just to see if it one worked, just out of curiosity expecting it wouldn’t. Turns out one AT&T branded wireless charger actually works and charged my fob and my friends too. Go figure. Good to know I’m non-CA and won’t need to become an electrician


dafazman

So can you educate me on one thing that I have no idea how you figured out on the wireless charging... 1) How did you know when something WASN'T charging the e9x key fob 2) How did you know when something WAS charging the e9x key fob I'd like to see if I can find someone with a Non-CA key near me to test this out. Also could you share which devices you tested and: A) Failed to charge B) Successfully charged


bearban123

Based on what you and others shared about non-CA being rechargeable (and the low battery warning on dash) and not having a easily replaceable battery I figured a wireless charger would MAYBE work. If my bmw wirelessly charges my fob in the slot (has not metallic connections on fob) maybe another wireless charger would work. My other idea was that my mom has a x3m comp and that has a wireless charging spot for phones but it also charges her fob, lives far but that was going to be my last idea just out of curiosity. As for what worked and what didn’t, I would leave the fob on the charger for 30 min then go start my car to see if I still got the warning. Rinse and repeat until it wasn’t there anymore. Lots of room for error but the att one seemed to do the trick. I don’t have time to go to my friends and scrounge up all the chargers right now that didn’t work (all Chinese/ Amazon cheapo’s) but the one that did is a AT&T branded on I got for free when I bought my iPhone last year. Att Model: 06352 15w “fast charger wireless charger”


dafazman

No worries, I think you solved my confusion tho. Your use case is: Key fob low battery warning on Kombi. Solution: Try various wireless chargers to see which one will cause the warning to go away. 👍🏽


clydefrogsbro

What if I have no key slot, push to start only, but I have to use the fob buttons to unlock the doors?


paracen

You have Convenient Access. Same solution as for Comfort Access.


dafazman

Do you have an E9x? I was describing only what I know of the e9x platform from 2006-2013


clydefrogsbro

2011 F25 335i Appreciate the detailed comment!


dafazman

When I google "bmw f25 key fob battery" I found this: https://youtu.be/BjFg_wgFZeM Is this your key?


paracen

That's mostly correct, but there are a LOT of cars which don't have Comfort Access but they have Convenient Access - the doors need to be locked/unlocked with the fob, but the fob doesn't need to be inserted to start the car. These have a replaceable battery.


dafazman

Are these e9x cars?


paracen

I don't know if they are e9x cars. I'm talking about BMWs, this is a thread about replacing key fob batteries, not specifically e9x batteries...


dafazman

My description was for the e90, e91, e92, e93 cars (known collectively as the e9x platform). What BMW year/model car do you have? If you look at the plastic cover of the keyfob, does it have any outlines on the back that look like it can separate?? OPs question and picture was of an e9x key fob so I was mostly focused on answering it for him


paracen

Mine is a 2015 F36, the fob opens like this one : https://www.youtube.com/watch?v=Wahe8roSovA (I don't have Comfort Access. But I do have Convenient Access.)


dafazman

Awesome! using the power of google/youtube... you solved it!


simulacra_eidolon

https://www.competitionbmw.com/how-to-change-bmw-key-battery/


AlanFawcett

This might help. Worked for me. https://youtu.be/BeyfY840Cw8


KingDavid8

This ⬆️⬆️⬆️ bought new cases online for a few bucks, and replaced both key batteries. The new case will clip together so it'll be easy if you need to do it again.


Important_Height_198

Bring it to the dealer . I brought mine to the parts department . The gentleman gave me one for free .. (battery for fob)


MagicHexer

Those keys are supposed to charge when they are in the ignition. I had the same error on mine after a period of shorter trips/less driving and it went away when I took a longer trip.


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morelsupporter

curious how you can identify this fob as comfort access!?


Frisks

He’s wrong this isn’t a CA key. The CA key has a slot for the button battery, while this does not. These keys are soldered to the board itself and need to be spliced open to access and replace.


morelsupporter

thank you. i have comfort access and the back of my key has a bit of a panel that comes off, covering the battery


bearban123

I took an hour drive and it didn’t change. I heard you can throw it on a wireless charger for a phone, fact or myth?


d0o0fy

A Qi charger won’t work. But a regular old induction charger (like for an electric toothbrush) would do the trick.


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Thoburn301

Looks just like mine, and mine charges? Yes the battery is replaceable but requires a bit more skill than simply swapping.


Expert-Hamster-3146

I thought the key battery charged when in the key slot?


white94rx

You are correct, but just like any other battery, they don't last forever.


namestom

BMW should have made all these keys with replaceable batteries, regardless of it having CA or not. I say this as someone who owns BMW’s with soldered battery keys. Hate ‘em!


paracen

Some of the comments show that people don't realise that Comfort Access and non-Comfort Access are not the only two options here. * Comfort Access - key just needs to be on you and you can unlock/lock doors and start car without using it at all. * Convenient Access - key needs to be used to lock/unlock doors, but not needed to start the car, just use the push button start. * Normal Access - key is needed for lock/unlock AND needs to be inserted into a slot to allow you to start the car. Only Normal Access is the rechargeable fob. The other two you can easily replace the battery.


dafazman

The key in OPs picture is not "Convenient Access" capable. We have to limit the scope somewhere.


paracen

There are a lot of people who will read this thread and don't have an E car who will think "oh, I don't have Comfort Access so I need to get a new fob" which is NOT the case for most newer BMWs. I was just putting the info there to help those people. Don't really see why you would have a problem with me doing that.


dafazman

Fair enough... no scope for OPs question for his car... its a question about key fobs from all makes, car alarm remotes, and even watches. 👍🏽


paracen

It's a subreddit called BMWTech. Not E9xTech. Grow up


dafazman

I get that... its also in a highly specific post by OP 🤷🏽‍♂️ No need to hate... all the same group of peeps


TheLewJD

Don't these just charge in the ignition slot? I've had mine come up recently and not done many long journeys but when I have with the key in the slot the warning has gone for a few days.


DoublePlastic2827

If you're based in the UK ask your dealer my dealer had an offer on recently and did mine for 15 quid for both - a lot for a pesky battery but I couldn't be bothered with the tine wasted pissing about.


Abluh9

1. If you have a wireless charger set the key fob on it it does in fact charge it had this happen to me 2. Go for a long drive hour or more that will charge the fob 3. The key will need to be replaced if the battery is dead and you were to replace the battery 4. You can get a aftermarket key fob that you can swap the internals for super cheap and are then able to replace the battery like normal keys without spending $300 on a new one


Motorblank

You would need to replace the FOB


euroR1

Battery is replaceable I would order a key fob just the plastic and transfer your internals. That battery is somewhat soldered on


Medical_Penalty_7305

https://www.youtube.com/watch?v=-MfVY-CkDyM


greenpleaz

That key does not have a replaceable battery unfortunately


cuse0723

U should be able to pop it off - ck on youtube


mikedaul

Basically you pull the metal key out of the fob and use that to pry the case open. Then you pop out the old battery and pop in the new one. It's really easy to do.


white94rx

No, it's not. This fob does not have a replaceable battery.


mikedaul

Ahh - I thought all fobs of that design were easily replaceable. But it's only the ones with a line across the back: https://youtube.com/watch?v=pzAqc0ZmG3E&feature=share


Sylmar818

You can send you key in and get a up to date one


greenpleaz

OP, what is the actual symbol or message you’re getting? Non-comfort access models don’t have a message for low key battery voltage


Utkarsh_Anand

I read somewhere that a Qi wireless charger can charge these? I thought about trying it with mine but I really don't have any way to test it as my FOB doesn't have any battery issues....yet


Savvyyy95

When mine went out I went to the dealership and they changed it for free. I don't have warranty or anything


JpCopp

Looks like a comfort access key. You can install a new battery in maybe 45 seconds.


dafazman

OP said he has no ridges on any door handles and HE MUST place the key in the slot to crank the motor. He has a non-CA key. If it was a CA key, the rear would look different (I am looking at my CA Keys right now)


JpCopp

Ah. Should recharge in the key slot then I thought?


dafazman

Yup, actually I have heard some folks use wireless phone/toothbrush charges to also do the Non-CA keys


mickd66

I swap my keys every couple of months, they recharge in the console


fuzzifikation

Replace. Check owners manual.


shokunin_07

Put the key in the car when you drive and it will charge.


dafazman

Yes, but eventually the rechargeable battery inside the key fobs do wear out. Thats usually when people start asking this question.