Key Batteries

[Mick F]

We have a remote operated key and a button to start the car.  So long as the key is in the car, you can start it.

The other day, I parked up waiting for Mrs Mick F and pressed the button to switch off.  The green key symbol should then extinguish, but it was flashing orange.  I don't know why, but I started up again and switched off off again and all was well.  Later, started again and drove home.  All been fine since.

However, it got me thinking about Battery life.  We've had the car for three and a bit years, and I've never fitted a new Battery.  The handbook suggests changing it every one to two years.

Nightmare scenario ............ you start up and drive away for a few hours and reach you destination and switch off.  The Battery could have died en route, and you'll be marooned miles from home.

What sort of warning do you get that the battery is on its last legs?  Was my flashing orange key symbol trying to tell me something?  Even if you fitted a replacement battery, how do you know it's a "good" battery?

Mick.

[Gerg]

1 hour ago, Mick F said:

how do you know it's a "good" battery?

I suspect I have had 'knock-off' CR2032 (same size as in a Yaris keyfob?) before.  They were internet bought, and claimed to be Panasonic branded, and a second batch were Maxell.  They didn't last as long as previous sets of batteries (fitted in a wireless house alarm).  The starting voltage was the same, at 3.3 volts, so that wouldn't help you to detect that they were fake.  They just discharged in half the time

If batteries were to be made as a counterfeit brand, then I imagine the most 'added value' would be to pass them off as a market leader, which would probably be Panasonic or Maxell, at a guess.  I don't remember seeing Duracell button cells around my part of the world.

'Savers' the chemist (part of Superdrug) sell Panasonic CR2032 batteries in packs of 6 for £2 in their high street shops, I haven't had any problems with mine yet.  I have bought Ikea branded CR2032 batteries in the past, with no problems, and unlikely to be counterfeit when they are bought in Ikea!

The remote control seems to flag these batteries as needing replacing at 3.05 volts, and many other devices seem to start misbehaving at around this voltage, which is odd given that the batteries are rated at 3.0 volts.

If you don't mind waiting quite a few weeks for delivery, cheap but functioning digital voltmeters can be bought from direct China for about £2.50 delivered.  I've inherited one - it's not as bad as you might expect, and handy to leave in the car.  It is surprisingly accurate when compared to other DVMs. For £4.30 you can buy a backlit DVM in a silicone sheath, complete with a continuity buzzer and plug-in temperature probe.  Probably too late to get one delivered as a stocking filler.  I'v not used this seller, or this model!

https://www.aliexpress.com/item/1005001279919079.html?spm=a2g0o.cart.0.0.20243c00ymLL65&mp=1

Or this one is about as cheap as they come:

https://www.aliexpress.com/item/4001309978210.html?spm=a2g0o.cart.0.0.39963c00DF11v4&mp=1

As long as you trust these people with your credit card details.  The website is clunky and a bit rubbish, by the way.

 

[HughA]

My key fob Battery expired a couple of weeks ago. The warning I got was that I sometimes had to use the physical key to open the drivers door, but I didn't have any problem starting the hybrid system.  The other clue I should have spotted was that the red light on the key fob didn't flash when I pressed the button, I only realised this when I replaced the Battery and wondered what the red light was! Got a pack of 2 Duracell 2032s from Amazon for £1.96 including shipping, next day delivery.

[Mick F]

Thanks guys.

We're OK for CR2032 batteries as we use them in a few things.  Any time we buy stuff, I always make sure it takes CR2032 and not something obscure. The CR2016 are the same, but a tad thinner and can be fine in some devices.

Red light eh?  I must look for that!  To be honest, we never look at the fob, just pressing the button!  Our car is supposed to have Smart Entry I believe, though when I've tried it, it doesn't seem to work.  Pressing the key fob button works of course!.

This is our key.

Mick.

[Parts-King]

Not all key fobs have a red light, most do, but not all. When they drop below 3V it's time to replace, some weird things happen with a low voltage, usually you need to get closer and closer to the door before it opens, or on some models, you get the warning light on the dash. You would not be marooned if you have a keyless type of fob and the Battery in the key went flat, hold the fob over the start button and press to start the car. I have people come in to say they have never replaced the batteries in years and seem surprised they need to spend a fiver, others will need replacing yearly, depends on use etc

 

[Mick F]

Ours has a red light, but just playing with it here in the livingroom over a cuppa, it seems the red light flashes so so quick, you might miss it.  It truly is a flash and come gone in an instant, and hardly worth the technology, as in bright light you wouldn't see it. If it gave a series of flashes, it might be worth it.

I have a multimeter, but by the time I'd opened the key and taken the Battery out to check it, I may as well have put a brand new one in there.

As I said, it's the same Battery in all the time we've owned the car. Bought from Snows Toyota Paignton in August 2017.  We are the second owner and it's now done 48,000 miles.  I'd like to think that Snows fitted new batteries in both the keys.

Mick.

[Mick F]

On 12/1/2020 at 5:18 PM, Mick F said:

The other day, I parked up waiting for Mrs Mick F and pressed the button to switch off.  The green key symbol should then extinguish, but it was flashing orange.  I don't know why, but I started up again and switched off off again and all was well.  Later, started again and drove home.  All been fine since.

Happened again today.

I pressed the start button again, and the flashing orange key went.

Any ideas?

Mick.

[HughA]

Did you actually change the Battery Mick?

[Mick F]

No.

The red light flashes bright and clear ............. but you have to be quick to see it as the flash is so brief.

Tried the spare key, and it flashes the same.

Mick.

[Catlover]

Greg, I glad to read you have had good experience with Panasonic C2032 batteries. I have bought Panasonic’s batteries from various sources, both C2032 and AA, been disappointed with them, not of the standard of a Panasonic tv or hi-fi. For key fobs I now stick with Duracell, for AA and AAA I use Asda or Tesco branded and charge them up on a Lloytron Battery charger that does both alkaline and rechargeable batteries, never let the alkaline go completely flat before recharging, that way can recharge about 10 times before useless.

[Mick F]

The orange flashing key symbol seemed to be happening more often, but only when switching off.

The key fob would lock and unlock the doors as perfectly as before, and never a single issue with switching on ................... only switching off.  Everything else was perfect.

Nonetheless, I've put a new Battery in.

I'll be noting if there's any changes to the switching off and see if the orange flashing key occurs again, and if it does, this forum will be the first to hear about it. 😀

Best wishes to all, Mick.

[TonyHSD]

5 minutes ago, Mick F said:

The orange flashing key symbol seemed to be happening more often, but only when switching off.

The key fob would lock and unlock the doors as perfectly as before, and never a single issue with switching on ................... only switching off.  Everything else was perfect.

Nonetheless, I've put a new battery in.

I'll be noting if there's any changes to the switching off and see if the orange flashing key occurs again, and if it does, this forum will be the first to hear about it. 😀

Best wishes to all, Mick.

Hi Mick, 

if it happens again even with a new key Battery this mean the new Battery is not up to the voltage, happened to me recently on a small digital scale. Purchased another new better quality and the scale went back to life. I also keep one extra Battery in the glove box for extreme situations. 
Regards 

[Mick F]

Tell, you what, I still have the old Battery and I do possess a digital multimeter, so I'll do some measuring later.  I'll test the one in the key and the old one too.

Back later to this and report the voltages.

Mick.

[Mick F]

Hi again.

Sorry, it wasn't a digital multimeter I have, but an analogue one.

Tronic lithium button cell CR2032 batteries from Lidl - bought them for some years for various devices.  They come in a tray of six, and described as 3v.

Old Battery is 3.2v and as we have a tin of various spent batteries that we take to the recycling when the tin is full ............. I checked a couple of old CR2032 ones too.  They sat at 3.2v as well.

New Battery in the key only went in a few days ago and we've only driven the car once since then.

New Battery sits at 3.4v

Mick.

[TonyHSD]

1 hour ago, Mick F said:

Hi again.

Sorry, it wasn't a digital multimeter I have, but an analogue one.

Tronic lithium button cell CR2032 batteries from Lidl - bought them for some years for various devices.  They come in a tray of six, and described as 3v.

Old battery is 3.2v and as we have a tin of various spent batteries that we take to the recycling when the tin is full ............. I checked a couple of old CR2032 ones too.  They sat at 3.2v as well.

New battery in the key only went in a few days ago and we've only driven the car once since then.

New battery sits at 3.4v

Mick.

Hi, I am not sure the voltage itself or the amperage is the problem with these buttons like batteries but with my scale the new that I had installed showed same error as the dead battery even though they have two more years to reach expiry date, bought a new ones of different make that have 2027 date and the scale works fine now, didn’t even bother to measure them. 

[Mooly]

Some lithium coin cells can have problems delivering current due to an internal oxidation process within the cell. This is a normal and unavoidable effect and has the effect of increasing the internal resistance of the cell and so causing the voltage to drop under load. Measuring the open circuit voltage of a cell doesn't always tell the full story.

Normally this disappears when the cell is called on to supply significant power and is brought into service. So new cells kept in storage can suffer this way.

This effect can also manifest itself when for example a keyfob is put away working for a few months and then brought back into use. It appears the Battery is dead when in fact it isn't, it just needs to be coaxed back into life by delivering current. The current needed to do this fully may be more than a keyfob can draw.

There is also the issue of very slight leakage (imperceptible to the eye) from the cells seal and it can be beneficial to clean a cell on both sides with a cotton bud and isopropyl alcohol and to also clean the contacts in the fob. 

 

 

[Mick F]

On 12/28/2020 at 8:58 AM, Mick F said:

The orange flashing key symbol seemed to be happening more often, but only when switching off.

The key fob would lock and unlock the doors as perfectly as before, and never a single issue with switching on ................... only switching off.  Everything else was perfect.

Nonetheless, I've put a new battery in.

I'll be noting if there's any changes to the switching off and see if the orange flashing key occurs again, and if it does, this forum will be the first to hear about it. 😀

Best wishes to all, Mick.

Driven half a dozen times since the new Battery, and all has been 100% perfect.  Therefore, it was the Battery in the fob that was on its way out.

This now begs the question ........... to me at least.

Why did the fob work perfectly in unlocking and locking, work perfectly in starting the car, work perfectly during the drive, but not work perfectly when switching off?

What's going on with the system when switching off?  Does it require more load from the Battery to switch off than any other operation?

Mick.

[TonyHSD]

3 hours ago, Mick F said:

Driven half a dozen times since the new battery, and all has been 100% perfect.  Therefore, it was the battery in the fob that was on its way out.

This now begs the question ........... to me at least.

Why did the fob work perfectly in unlocking and locking, work perfectly in starting the car, work perfectly during the drive, but not work perfectly when switching off?

What's going on with the system when switching off?  Does it require more load from the battery to switch off than any other operation?

Mick.

Perhaps to warning you that you need a new Battery soon. 👍

[Mick F]

1 hour ago, TonyHSD said:

Perhaps to warning you that you need a new battery soon. 👍

Yes, of course!  

But why didn't it warn me before I started the car, or during the drive?

If it had done either, I could have driven to a shop to buy a new Battery.  Telling me that I need one after I get home is a bit silly.

Mick.

[Mooly]

17 hours ago, Mick F said:

This now begs the question ........... to me at least.

Why did the fob work perfectly in unlocking and locking, work perfectly in starting the car, work perfectly during the drive, but not work perfectly when switching off?

Possibly temperature related. Warm house, key in pocket etc and then in the car it cools somewhat and the cell can not deliver the required current. That is not uncommon to a cell that is marginal performance.

[Roy124]

On 12/2/2020 at 12:09 AM, Mick F said:

Thanks guys.

We're OK for CR2032 batteries as we use them in a few things.  Any time we buy stuff, I always make sure it takes CR2032 and not something obscure. The CR2016 are the same, but a tad thinner and can be fine in some devices.

Red light eh?  I must look for that!  To be honest, we never look at the fob, just pressing the button!  Our car is supposed to have Smart Entry I believe, though when I've tried it, it doesn't seem to work.  Pressing the key fob button works of course!.

This is our key.

Mick.

Got a smart key warning on my MY22 Yaris Cross.  No sweat, I have loads of CR2032 batteries.

Open key, rats, it uses CR2450.

FYI, a CR2450 is 24mm wide and 5.0mm thick.  Trip to the dealer is probably easiest.