Key Fob/Battery question

[Big Bad Boris]

I’ve read a few threads on here around fob batteries failing and how to re-code the fobs if they lose their marbles & cease to function etc. Not sure I’ve seen one that reflects my current issue.

2-3 weeks ago one fob suddenly stopped working completely, I used the other one to open the car and used the inoperative one for a 2 hour round trip to see if it needed charging, made no difference, so I have been using the one fob (been meaning to get it sorted since).

Last night using the good key, I drove 8 miles to the station, at home the car opened and started as normal. When I got back to it in the station car park about 5 hours later, I pressed the open door button, the interior light came on but the doors did not unlock. It was pi55ing with rain, so after a couple more pushes I quickly took the key out of the fob & opened the door manually. As soon as I opened the door manually the alarm sounded, stopping when I inserted the key in the dash, at which point the low key fob battery warning came up on the dash. Oddly it did lock the car when I stopped on the way home, but I had to go the same route, key, alarm sounding etc to re-start.

Is it simply after12 years both (rechargeable) batteries in the fob are knackered and need replacing (it’s a 09, 30i) or are the other possibilities that might be causing the described issue (e.g. does the ignition based charger in the car ever fail)? Also, follow up question, why does the alarm sound immediately after unlocking the door manually? Most cars give you 20-30 seconds to insert the key before sounding the alarm.

I know car battery causes many issues on these babies, so for clarity the battery is around 15 months old and was charged for a day about 2-3 weeks ago with my C-Tek.

 

[Argyll Andy]

Can’t say if the fob batteries are the root of your issue but if it is have you tried to fully charge them using an electric toothbrush charger? Even if they only charged them briefly it MAY confirm that the fobs are working ok and it’s the batteries that are gubbed.

If it is the batteries I had to replace these on my E90 and they were relatively easy too do. Get the key in a vice, split carefully using a craft/Stanley knife and pop the solders holding the original battery in and replace with like for like.

I paid a bit more and bought Panasonic branded ones which were circa £10 for two. A bit of gorilla glue and back together. It needed a light sand to get the residual glide off of the outside.

Whatever it is I hope you get sorted quickly and cheaply

 

[Big Bad Boris]

Can’t say if the fob batteries are the root of your issue but if it is have you tried to fully charge them using an electric toothbrush charger? Even if they only charged them briefly it MAY confirm that the fobs are working ok and it’s the batteries that are gubbed.

If it is the batteries I had to replace these on my E90 and they were relatively easy too do. Get the key in a vice, split carefully using a craft/Stanley knife and pop the solders holding the original battery in and replace with like for like.

I paid a bit more and bought Panasonic branded ones which were circa £10 for two. A bit of gorilla glue and back together. It needed a light sand to get the residual glide off of the outside.

Whatever it is I hope you get sorted quickly and cheaply

Thanks double A.

I have found an old toothbrush charger in the loft (sometimes keeping old sh1t is helpful ). Assuming it works, I am currently attempting to charge the key fobs, I am presuming it’s just a matter of balancing the key on top?

Do you happen to remember the reference number for the replacement batteries, obviously I need to crack open the fobs before I can actually eyeball them.

Also does anyone know how to stop the alarm sounding when opening the door with the physical key?

 

[Rucky]

if your keys are a few years old - get them refurbished and ask for a battery change too.
I have used this guy successfully on 2 Z4's.

https://www.themasterlocksmith.com/product/bmw-replacement-case-key-blade/

 

[mcbutler]

Is your card standard access Boris or is it keyless entry/start?

 

[Big Bad Boris]

Is your card standard access Boris or is it keyless entry/start?

It’s standard remote unlock, insert key in dashboard system (no buttons on the doors on anything). After using Mr AA’s suggested toothbrush charger trick one of them appears to be working properly again now, while the one that packed up a couple of weeks ago is still as dead as a dodo despite several hours charging.

My teeth are lovely and clean though

 

[Argyll Andy]

Can’t say if the fob batteries are the root of your issue but if it is have you tried to fully charge them using an electric toothbrush charger? Even if they only charged them briefly it MAY confirm that the fobs are working ok and it’s the batteries that are gubbed.

If it is the batteries I had to replace these on my E90 and they were relatively easy too do. Get the key in a vice, split carefully using a craft/Stanley knife and pop the solders holding the original battery in and replace with like for like.

I paid a bit more and bought Panasonic branded ones which were circa £10 for two. A bit of gorilla glue and back together. It needed a light sand to get the residual glide off of the outside.

Whatever it is I hope you get sorted quickly and cheaply

Thanks double A.

I have found an old toothbrush charger in the loft (sometimes keeping old sh1t is helpful ). Assuming it works, I am currently attempting to charge the key fobs, I am presuming it’s just a matter of balancing the key on top?

Do you happen to remember the reference number for the replacement batteries, obviously I need to crack open the fobs before I can actually eyeball them.

Also does anyone know how to stop the alarm sounding when opening the door with the physical key?

Sorry BBB for the delay, busy couple of days. The ones I used were something like https://www.ebay.co.uk/itm/164022903951?epid=557399337&hash=item263086e48f:g:X~kAAOSwRs1eFZnv

You’d need to make sure they were the same as yours. The one thing that’s really important is the spacing of the pegs.

I notice you’ve got one working via the toothbrush charger that’s what happened with me, one was revived, one was gubbed. Revived one kept working, other one swapped out. I now alternate my keys and every now and then stick the, on the toothbrush charger for a full top up.

At least you’ve now got a key working. Has this stopped the alarm issue?

 

[Big Bad Boris]

Yes, now it seems to be properly charged the good one is working as it should, interior light comes on, doors unlock alarm is switched off etc. Hopefully it will hold charge going forward.

Looks like the other one is going to need a new battery, I have a mate round the corner that is pretty handy with a soldering iron so I’ll try and get him on the job.

I see you can buy aftermarket clip together replacements cases on FleaBay etc. Are these a better option than supergluing the busted original case back together?

 

[Argyll Andy]

Tbh I never really considered a replacement fob. A lot of the cheaper ones I looked at didn’t look very good quality so I decided to try and re-glue the original.

It may also be worth leaving the one that’s not working on charge overnight. Can’t say it’s the same but I remember reading on either an electric toothbrush or razor that if completely flat or first time charge it can take up to 12 hrs to charge.

 

[Argyll Andy]

It went back not too bad (split one on the left) and I’ve just looked out the spare battery and there’s some ref no’s visible

 

[Big Bad Boris]

It went back not too bad (split one on the left) and I’ve just looked out the spare battery and there’s some ref no’s visible

Thanks dude, I did charge the non co-operative remote for about 24 hours in various positions on the toothbrush charger, but it still as dead as a dodo.

So it looks like it’s out with the scalpel and soldering iron for that one.

I can’t quite make out the reference number on battery in the photo, looks like XX2020, what are the two letters? There are a few similar looking items such as; VL2020 / ML2020, but from what I can make out it doesn’t look like either of those?

 

[colb]

Seems its normal for the alarm to sound if the car is opened with the key when it was previously locked using the central locking button on the key. My E85 performs in that way.

 

[Argyll Andy]

It went back not too bad (split one on the left) and I’ve just looked out the spare battery and there’s some ref no’s visible

Thanks dude, I did charge the non co-operative remote for about 24 hours in various positions on the toothbrush charger, but it still as dead as a dodo.

So it looks like it’s out with the scalpel and soldering iron for that one.

I can’t quite make out the reference number on battery in the photo, looks like XX2020, what are the two letters? There are a few similar looking items such as; VL2020 / ML2020, but from what I can make out it doesn’t look like either of those?

Here you go, also 17mm post to post on the one I’ve got that worked in my E90 fob HTH

 

[Big Bad Boris]

So an update, which may help anyone with similar rechargeable remotes going forward.

With thanks to BIG Double A up in Scotlandland, I was able to confidently order the correct replacement batteries etc. for my remotes. I decided to chance a couple of brand new clip together remotes rather than re gluing the old ones. Found an EBay seller (in Germany) that sold the full kit of 2 new remote cases, 2 new batteries and even the little BMW emblems to stick on for about £35.

I enlisted the help of my mate round the corner as he’s pretty handy with a scalpel and soldering iron and within the hour I had two new remotes that are almost impossible to distinguish from the original, I am a happy bunny

Again big thanks to Andy for his help with this one

Photo of replacements….

 

[Argyll Andy]

Glad you got all sorted bud

Might be worth posting a link to the seller of the fob kits as at that price probably makes sense to replace since you’re happy with the quality

 

[Big Bad Boris]

This is the seller I purchased from. It now shows they are out of stock, they were offering a discount for purchasing more than one item.