To reduce the risk of losing my key while away, I'm considering hiding the key under the car while it's parked at airport.

Ignoring the security issue for now I have a question.

It's a remote door locking key, like a lot these days, but also enables the starter button.

While the key is local to the car does it "interact" with the cars electrics? I'm thinking additional security risk and/or battery impact.

My logic is that it must talk to the car when I'm sitting in it, so is it try to while it's under the car?

 If you hide the key under the car I'll be very surprised if your car is still there when you get back.

26 minutes ago, Bobr said:

 If you hide the key under the car I'll be very surprised if your car is still there when you get back.

How likely is it that someone will be roaming around the vaste Heathrow car parks in the vain chance of finding my well hidden key. Anyway that's a risk for me to decide, what I want to know is if there is a technical issue.

Me and my brother sometimes leave a car with key for the other to collect. We always put the key in the back of a rear wheel. Entails kneeling down and reaching round the back of the wheel.  Of course not all that good if you have alloys with big gaps in where someone might see the key. And make sure it’s not over a drain.  I don’t know anything about the answer to the original question

Just now, isetta said:

Me and my brother sometimes leave a car with key for the other to collect. We always put the key in the back of a rear wheel. Entails kneeling down and reaching round the back of the wheel.  Of course not all that good if you have alloys with big gaps in where someone might see the key. And make sure it’s not over a drain

Thanks for advice, but still need my techy question resolved, before I even worry about the obvious risks.

19 minutes ago, Clyd said:

How likely is it that someone will be roaming around the vaste Heathrow car parks in the vain chance of finding my well hidden key. Anyway that's a risk for me to decide, what I want to know is if there is a technical issue.

The keys, as I know to my cost, can be detected by a laptop with special software from 20 yards away.

Depends on the age of your car.

If you have the newer sleepy fobs then then they switch off after a short period of idleness (such as hidden up under a bumper).

If you have the older fobs the car will be permanently unlockable.  However, the immobiliser part isn't active until inside the car.  So if anyone did get in just by trying the door handle on every car, they'd get a 'key not in car' warning and it wouldn't start.

You can get a magnetic key box, which may be better than leaving it loose.

So you think the only thing you might lose while away is your car key? How do you not lose anything else? 
 

Do a practice run at home and answer your query yourself.

8 hours ago, MarksST said:

So you think the only thing you might lose while away is your car key? How do you not lose anything else? 
 

Do a practice run at home and answer your query yourself.

I think it's less about the likelihood of losing at - more about the consequences if he did.

No consequences to losing any of the things he does take away with him?

13 minutes ago, MarksST said:

No consequences to losing any of the things he does take away with him?

Tbf, my Dad had has wallet nicked on holiday in Europe a few years ago.  Caused a lot of hassle.  Not taking any unnecessary items doesn't seem like a bad idea.

If he can safely hide the key near the car, I don't see the problem.  Personally I'd want it wrapped in tin foil and hidden behind the bumper or ideally something like a fog light grill if they're push fit rather than screwed.

Already been said but newer models have key deactivation which stops the key transmitting or talking to the car after say a couple of minutes of it being totally still. Older models, I guess are always connected to the key when it is in range.

As for leaving keys, where I work and many other places I know always leave wagon keys for other drivers usually under the front grille / engine bay of the cabs. Seems standard practice when on yards and lorry parks. 

Thanks for this response. I was getting rather fed up with the lectures about the security, which I'm well aware of and prepared to take that risk.

But I think you've confirmed my real concern about the "talking to the car".

I believe my concern was real, but you've given me a degree of reassurance that it sleeps after a while. Thanks

To answer your original question,

Yes, the new keys go to sleep after 20 minutes of inactivity, but if it's stored too close to the sensor it will keep the car alive, even though you've locked the car.

My advice would be:

Don't lock the car

Place the key where you want to hide it.

Get in the car and try and turn the ignition on

If you get ignition, keep moving the key towards the rear of the vehicle until you get "Key not Found" warning when you try to turn on ignition.

Then you've found the place to store the key

If you have keyless (passive entry) you will not be able to store the key under the car at all, unless you deactivate keyless (passive) entry

Thanks for this, good advice. The key is push button on the fob for the doors but hands free for the ignition.

I will test it as you suggest, but I think I know the result. If as I suspect the car won't start if I place it at the rear of the car, does this replicate the same situation as having the key in the house. In other words perfectly acceptable for a long period if time ?

The point I'm labouring, is I need to be assured there is no ongoing "communication" going on between the car and key, which could result in battery issues after parking the car for 4 weeks.

Thanks for you patience!!

Just now, Clyd said:

I will test it as you suggest, but I think I know the result. If as I suspect the car won't start if I place it at the rear of the car, does this replicate the same situation as having the key in the house. In other words perfectly acceptable for a long period if time ?

Yes, if it can't talk to the key then you're good to go. Security is on your own head, obviously, but this will ensure you don't come back to a flat battery.

You could get a small pouch that blocks signals (is it called faraday or something??) put the key in that, then place it in a magnetic box on the underneath of the vehicle.

The keyless ignition sensor is usually underneath the centre console, if that helps

You can just wrap the key in tinfoil for this one time rather than buying a faraday pouch.  It'll have exactly the same effect.

 

I've never lost  my car keys in the 40+ years traveling abroad or otherwise. But I have lost 2 cars temporarily at the airport( forgot where I parked them. ) 

Car keys when away just get left in a pocket in the suitcase. And no I haven't lost a suitcase yet. Have picked up someone else's case by mistake once, but that's another story. 🤣🤣