If you think putting your car key through the washing machine is bad...

[Ian Key]

I was told by the famous R F Potts of Derby, who are a specialist of computer electrical and electronic components and equipment, that the main thing when replacing these sort of batteries is not to touch both sides with your fingers at once and if possible use plastic tweezers so as not to partially discharge them.

 

[decrep]

I suspect it was the dent in the battery that did for it.
But don't trust that fob for a while, getting run over may have caused a partial short somehow, and could flatten the new battery as well.

Leave it at home for a week and use the spare, If it still works after that, it should be fine.

 

[Rolfe]

Thanks for the tip!

 

[Rolfe]

I suspect it was the dent in the battery that did for it.
But don't trust that fob for a while, getting run over may have caused a partial short somehow, and could flatten the new battery as well.

Leave it at home for a week and use the spare, If it still works after that, it should be fine.

Well, you were right. There seems to be a partial short, as the new battery only lasted three days. On Sunday evening I got a "key battery low" alert when I got into the car, and the next time I tried to use it, it was dead.

Do you think this might be repairable, or am I going to have to spring for a new key?

 

[Archev]

Well, you were right. There seems to be a partial short, as the new battery only lasted three days. On Sunday evening I got a "key battery low" alert when I got into the car, and the next time I tried to use it, it was dead.

Do you think this might be repairable, or am I going to have to spring for a new key?

If it were mine I’d be tempted to take apart and give the internals a good squirt of electric terminal cleaner and leave it on a bit of kitchen paper somewhere warm and dry for a couple of days. Fit a new battery and see if it’s working again. But I would carry the spare key with me just in case until I was pretty sure all was well.
At the slightest hint of continued trouble I’d order a replacement.

 

[Alb]

I'd bite the bullet and order a new fob. You'll always have a reason not to trust this one.

 

[Rolfe]

As I do have another key, I'll try Archev's suggestion first. It can't do any harm. Even as things stand, the damaged key seems good for three days. (Both times it took three days to fail.) If it does seem to work I can keep the damaged key as the spare and test it from time to time, if not then I'm no worse off.

I can try asking my (new) dealer if he thinks it can be repaired.

 

[decrep]

I'm sure the dealer won't know if it can be repaired.
If repairing is an option the best bet would be a local electronics tech, maybe somebody that fixes phones?
I'm with Archev here, there could be moisture inside, his method of drying it out is as good as any.
It's certainly worth a try,

 

[Rolfe]

I was wondering if it might be worth asking the computer repair shop.

 

[decrep]

You can certainly try, but I think they would do something similar to Archev's method first if that didn't work, they might find a simple fault.
But these days electronic techs tend to replace the whole board, and I'm guessing that would be as much as a new fob.
So I think follow Archev's procedure, but if you find that too difficult, then try the computer guys.

 

[mystreet]

Keep it as the spare, don't think that you have to keep it permanent powered, so pop a battery in once a month and just use it for a day. In the three years of owing our ZS, never once used the second fob. Only taken to the sevices. Still working fine when returned.

 

[Archev]

Keep it as the spare, don't think that you have to keep it permanent powered, so pop a battery in once a month and just use it for a day. In the three years of owing our ZS, never once used the second fob. Only taken to thd sevices. Still working fine when returned.

I usually swap keys every few months. IF the dealer replaces the batteries at service time I like to think I’ve had some use of it and some of the power from it.
But that’s just my Scots psyche

 

[Rolfe]

I've never known a dealer replace a key battery.

 

[Archev]

I’ve actually seen mechanics replace them and wondered if it was indeed new ones being fitted. I haven’t seen any wrappers.

 

[Everest]

I was told by the famous R F Potts of Derby, who are a specialist of computer electrical and electronic components and equipment, that the main thing when replacing these sort of batteries is not to touch both sides with your fingers at once and if possible use plastic tweezers so as not to partially discharge them.

Well... I'm not sure what they mean by "partially". A CR2032 battery is 3V and the resistance of human across skin is likely to be around 1M Ohm. As V=IR, that will result in a discharge of approx. 3-micro Amps. A CR2032 has a capacity of around 200mAh, so with a discharge rate of 3uA, the battery would be discharged in just over 65,000 hours from holding it alone. That's over 2700 days = nearly 7.5 years.

So... holding the battery for say 1 minute would discharge it about one four-millionth of its capacity - which I guess is technically a "partial discharge"

On the other hand, I do recommend avoiding excessive handling of these battery so as not to get grease and muck from fingers onto the surface where the contacts are made.

 

[OriginalBigAl]

Its on the schedule for the second service, if they can apply an enormous mark up for a " special " battery they most likely will. Same with washer fluid, Top up before you go , they test the washers and wipers then charge you for a full bottle of branded fluid to top up 100ml, the remainder for the mechanics and /or friends personal usage. Am I coming across as irritated , angry, and expected to pleasantly say ," thank you "as I grudgingly insert my card into the payment machine whilst the weakly smiling Workshop manager thinks " sap ".

 

[Archev]

Well... I'm not sure what they mean by "partially". A CR2032 battery is 3V and the resistance of human across skin is likely to be around 1M Ohm. As V=IR, that will result in a discharge of approx. 3-micro Amps. A CR2032 has a capacity of around 200mAh, so with a discharge rate of 3uA, the battery would be discharged in just over 65,000 hours from holding it alone. That's over 2700 days = nearly 7.5 years.

So... holding the battery for say 1 minute would discharge it about one four-millionth of its capacity - which I guess is technically a "partial discharge"

On the other hand, I do recommend avoiding excessive handling of these battery so as not to get grease and muck from fingers onto the surface where the contacts are made.

Interesting- I came across that type of battery in some of the taps and things I serviced and they appeared to have lasted a good number of years sometimes.

 

[Everest]

There seems to be a partial short, as the new battery only lasted three days.

I was wondering if it might be worth asking the computer repair shop.

Sadly these days, with multi-layer PCBs and surface mounted components, there is little scope for board-level repair of such devices.

Drying out the fob for a few days (airing cupboard / conservatory etc.) is a worthwhile and free exercise, but I wouldn't hold your breath.

With a discharge happening within just 3 days, my finger-in-the-air guess is a short, possible within one of the buttons, that is causing the fob to continually transmit and run the battery down. A close visual inspection with a jeweller's eyeglass may turn up something, but I don't hold out much hope.

 

[Rolfe]

I'll have a look anyway. I don't think any moisture got into the key though.

 

[MG Clive]

To be honest @Rolfe, if my key got dropped outside on the tarmac, run over, scratched and dented, and stopped working, I don't think I'd ever trust that key again. You may have to spend some of your Scottish pounds on a new one.