keyfob battery failing with *no* warning

[Robbijay]

These cars/remotes are far too fussy considering it could leave you stranded.

[DBSurrey]

New Varta ones have 3.2V.  I have found that 3.0V is not sufficient (same with my Mazda 6 fob).

[Gapp]

That’s interesting! Seems strange they are that sensitive to voltage.

[Karock]

Measuring open circuit voltage with a voltmeter can be misleading it is the batteries capacity to maintain a specified voltage while delivering current to the load that is important.

 

If open circuit voltage drops much below 3.0 then the battery  is most likely duff.  You really need to measure the voltage with the battery in the fob, not straightforward.

 

[agedbriar]

4 hours ago, Karock said:

Measuring open circuit voltage with a voltmeter can be misleading it is the batteries capacity to maintain a specified voltage while delivering current to the load that is important.

 

True.

 

To assess the remaining operative life of a battery, the voltage must be measured with the battery under an appropriate load. Either using a dedicated battery tester or the particular testing mode that some multimeters offer.

 

Not to be confused with the testing method for assessing the state of charge of the car's conventional lead-acid battery, which is done by measuring the battery voltage at no-load.

 

Edited 25 November, 2021 by agedbriar

[DBSurrey]

Update :  Exactly after a year after replacing, the CR 2025 Varta battery in my key fob died.  Luckily I was at home and just fetching something from the car (like last time - phew!).  The voltage on the expired battery (no load) was 3.00V.  The voltage on the new Varta battery (no load) was 3.24V.  Rather than keeping a spare in the glovebox I have decided to keep one in my wallet, together with a 2p coin to open the fob and a safety pin to remove the dead battery.  This will save me trying to open the car door manually with the key (probably on a dark wet winter's night.  Hopefully I won't drop the new battery down a drain, although I still keep a couple of spares in the glove box).     That's technology for you !

[agedbriar]

3 hours ago, DBSurrey said:

I have decided to keep one in my wallet, together with a 2p coin to open the fob and a safety pin to remove the dead battery. 

 

+ 1 

 

 

[Gomezz]

4 hours ago, agedbriar said:

  7 hours ago, DBSurrey said:

I have decided to keep one in my wallet, together with a 2p coin to open the fob and a safety pin to remove the dead battery. 

The most sensible place to keep one, as long as you have your wallet !  Better than keeping it in the glove box when the doors don't open.

[StEdmund]

On 27/11/2021 at 16:59, Gomezz said:

The most sensible place to keep one, as long as you have your wallet !  Better than keeping it in the glove box when the doors don't open.

 

By all means, keep a spare battery in your wallet; by all means, keep batteries all over the place but DO ..... 

 

A Keep one in the glove-box and

B Practise getting into the car using the mechanical key when the keyfob battery has died.

Edited 29 November, 2021 by StEdmund
Speeling

[johnkelkin]

Hi all,

Just had a similar issue with mine. Went out to car, wouldn't unlock by 'touch' (my usual method), nor by using buttons (doors/boot) on fob. No red light when button pushed. I don't recall seeing a caution on the display but I usually jump in, put my foot on the brake & press start which may mean that I missed it.

Luckily I was at home, grabbed the unused spare & it worked fine (I don't recall ever changing the battery in the spare but it is an Energiser, not a Panasonic as most seem to report the OEM battery brand being, the failed(?) battery is a Panasonic). Swapped the Energised battery into the other fob - nothing, no red light. Put it back into the 'spare' & it worked fine. 😕

Head scratched.

Nipped down to my local Co-Op & bought a card of 4 Duracell CR2025s. Fitted 1st one - nothing. Fitted 2nd one - nothing. Fitted 3rd one - working but with the exception of the button to lock, no red light  when I press it & no reaction from the car, 'Unlock' & Boot 'unlock' both cause the red light to activate & the car responds as normal. KESSEY works as normal & car starts.

Any experiences like this or thoughts?

Thanks.

[Daveybm]

My Karoq 1.5 SEL 2021 with Kessey takes a CR2032 battery which is slightly thicker than the CR2025 battery, are you sure that you are using the right one as I understand the vehicles with Kessey use the thicker one.

Edited 20 September, 2022 by Daveybm

[DBSurrey]

My 2018 Karoq was delivered with Panasonic cr2025 batteries.  I have used 2025 when replacing them.  I might try a 2032 next time I replace.

[Gapp]

Hi all, my batteries are definitely Panasonic CR2025 and the one in the picture was fitted on the last service at my dealership 2 months ago.

I don’t think the 2032 would be correct one to use as it’s almost 1mm thicker.

The obvious difference between the two battery types would be thickness. The CR2032 is 3.2mm thick while the CR2025 is 2.5mm thick, 2025 - (170 mAh v 235 mAh) and is not recommended by Skoda.

mine is a KESSY SYSTEM and I only had one instance of faulty operation almost 2years ago.

 

[NottsIan]

I think the later keys ( MY2021 on) were slightly different and take a CR2032. Mine (Oct 21) certainly came fitted with a CR2032 and IIRC is marked inside as requiring a CR2032

[Gapp]

If it states that it req CR2032 in the 2021 MY on specification then they have updated the key unit but I would be careful about fitting the CR2032 battery in the older key unit as it could damage the fitting and possibly result in needing a new unit and they are not cheap! 
be careful if you want to try fitting the 2032 batteries in the old series units it could be an expensive result.

[Gapp]

The handbook states the correct way to replace the battery (page 288) and you need to hold any button for 5 seconds after removing the old battery before you put the new battery in and the unit needs to be synchronised if the doors will not lock/unlock afterwards (page63) and the correct battery specification must be used.

Synchronising the remote control
If the buttons on the remote control key have been operated several times be- yond the effective range of the system or the battery in the remote control key has been replaced and the vehicle cannot be unlocked using the remote control, the key must be synchronised.
› Press any button on the remote control key.
› Unlock the door with the key in the lock cylinder within 1 minute of pressing
the button.

 

 

I hope this helps with the battery problems.

[johnkelkin]

11 minutes ago, Gapp said:

The handbook states the correct way to replace the battery (page 288) and you need to hold any button for 5 seconds after removing the old battery before you put the new battery in and the unit needs to be synchronised if the doors will not lock/unlock afterwards (page63) and the correct battery specification must be used.

Synchronising the remote control
If the buttons on the remote control key have been operated several times be- yond the effective range of the system or the battery in the remote control key has been replaced and the vehicle cannot be unlocked using the remote control, the key must be synchronised.
› Press any button on the remote control key.
› Unlock the door with the key in the lock cylinder within 1 minute of pressing
the button.

 

 

I hope this helps with the battery problems.

Thanks all. The issue is not that the key is not sync'd, but that it had stopped functioning i.e. no red light when button pressed.

[Routemaster1461]

I replaced the battery in mine. The one in the key was a 2032, and I replaced with a Panasonic. The key didn't need any synching, it just worked.  I now carry a spare in my wallet and one in the car.

[agedbriar]

7 minutes ago, Routemaster1461 said:

I now carry a spare in my wallet and one in the car.

So do I ...  

[DBSurrey]

I also carry a coin to prise open the fob to get at the battery.

[vulcan]

Sometimes the new battery has a little warning sticker on one side and that stops it making contact and working that's what happened to me !

[roadarman]

My 2018 Octavia vRS displayed 'Key battery low' so I fitted a new Duracell CR2027 from an unopened pack dated 2027.

The remote was DEAD.

I tried 'syncing' the key as described in the handbook but nothing happened and then the alrm went off !

I locked the car using the spare remote and that stopped the alarm.

I then noticed that the red light did not come on when I pressed any button.

I then fitted the other new CR2025 from the pack of 2 - same result = DEAD.

I check the voltages and the old Panasonic showed 3V and the NEW Duracells both showed 3.2V.

However, before visiting the dealer I bought a pack of 2x VARTA CR2025 from Screwfix.

All sorted, the remote worked first time and the key did not need 'syncing'.

I won't by Duracell in future !

Incidentally this was the first time I had changed the battery so had got over 5years life from the Panasonic battery.