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@AHG, what you say makes some sense but I just cant believe that the key is transmitting 24/07, even at an extremely low power level.

 

If that was the case then a battery that size wouldn’t last 13 days, let alone 13 months!

 

From what I have read, it is the car that is transmitting 24/07 as it has a much bigger battery on board!! and the key only responds (transmits) in certain circumstances when it hears (receives) the signal from the car.

 

It is quite difficult to find a detailed explanation that goes into the exact detail of how keyless works, but I did find this which makes sense: - (see post wsh on Dec 5, 2018)

 

https://news.ycombinator.com/item?id=18608624

 

As suggested by @aldfort, it would be very interesting to hear from anybody who has had a mk8 for a year plus and turned off “Keyless Entry” from day 1.

 

I suspect, anybody who did this would find that their key fob batteries are still going strong after way over a year.

 

I suggest that this would be because when you turn this option off, it simply stops the car from transmitting the constant signal so the keys never receive it and never respond, meaning they only ever transmit when a lock/unlock button is pressed or when the key is in the car to allow the starting of the engine. (just like a key without keyless locking/unlocking functionality)

 

If your theory is correct, then turning this off would have no affect on the battery life unless it somehow changed the way the key operated, which again, I doubt very much would be the case.

 

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@AHG wow. Boy.   Does your R need to come soon. 😀

I’m thinking of donating mine to this cause.  

Thanks. Good to know. I bought a ton of those a while back. Since my S3 uses them and I thought they’d fit the 8R and the Tiguan. Well, 2 out of 3 are better than 1 :-)

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I do think there will be no effect

EasyOpen only changes the logic of how the car responds to proximity of the key (open instead of just enable touch open) but not the actual sensing, which is the transmitting and receiving part, that consumes energy.

Regarding if the key is transmitting 24/7 (intermittently of course, not continuously) or just receiving (listening) 24/7 and transmitting only in response when it “hears” the car, I don’t have precise info, but continuous listening takes energy as well, and not much less.

Point being, battery usage that happens all the time, will have as a much higher effect on battery life than something that happens for 1-2 minutes per day (which is 0.1% of the time) even if its usage is 10/100 times higher.

I think tech has gone a long way.

Only two decades ago you couldn’t have anything be “switched on” on battery power for a long time, without it dying after a few days, at best. Even without doing anything, just “power on”. It would die after a few days max.

But current transmission and encryption tech have evolved to much that it take so little power, they can stay on for a full year (or more) on a 2025 or 2032 battery. Amazing IMO.

For comparison, If you take your laptop, turn off WiFi and BT, keep the screen dark (lid closed), and just sit there doing nothing but being In sleep mode … the battery (much bigger than 2032) will not last for a few weeks or months, even in sleep mode.

So 13 months (or more) out of a 2032 is quite impressive

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16 hours ago, AHG said:

I do think there will be no effect

EasyOpen only changes the logic of how the car responds to proximity of the key (open instead of just enable touch open) but not the actual sensing, which is the transmitting and receiving part, that consumes energy.

Regarding if the key is transmitting 24/7 (intermittently of course, not continuously) or just receiving (listening) 24/7 and transmitting only in response when it “hears” the car, I don’t have precise info, but continuous listening takes energy as well, and not much less.

Point being, battery usage that happens all the time, will have as a much higher effect on battery life than something that happens for 1-2 minutes per day (which is 0.1% of the time) even if its usage is 10/100 times higher.

I think tech has gone a long way.

Only two decades ago you couldn’t have anything be “switched on” on battery power for a long time, without it dying after a few days, at best. Even without doing anything, just “power on”. It would die after a few days max.

But current transmission and encryption tech have evolved to much that it take so little power, they can stay on for a full year (or more) on a 2025 or 2032 battery. Amazing IMO.

For comparison, If you take your laptop, turn off WiFi and BT, keep the screen dark (lid closed), and just sit there doing nothing but being In sleep mode … the battery (much bigger than 2032) will not last for a few weeks or months, even in sleep mode.

So 13 months (or more) out of a 2032 is quite impressive

Sorry, but I am not quite sure what you mean by the key is transmitting 24/07 but not continuously?

 

In your theory of it “transmitting 24/07” what “triggers” the key to transmit then if it’s not “continuous” and it never receives a signal from the car? (because it is either stored out of range or in a faraday pouch)

 

If we take your example of a key, which is used, only transmitting lock/unlock signals for 1-2 minutes a day, even 1 minute a day, over the space of a year (which we will say is the average battery life) is 365 minutes, so just over 6 hours of higher current transmitting!

 

If you accept that they key is also constantly receiving (which I think you do?) do you not think that then adding 6 hours of transmitting lock/unlock/turn on headlights commands over a year on top of that will not have much of an affect on the life of such a small battery?  

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Sorry for not elaborating.

When I wrote “all the time but not continuous” I meant it has a duty cycle (as all of these devices do, other no battery would ever last).

For example, if it listens for transmissions for 0.1sec out of every 0.5 second, so it is “24/7” just intermittently and not continuously (most electronics work like that).
In the example here there is a 20% duty cycle, which means the batter will last 5x more time than it would had it been listening continuously. It can be 10x or more.

I do not know if it is transmitting or just listening, as I wrote, and I do agree that transmitting takes up more energy than listening. But it is important to realize that energy is needed for listening as well, while although it is t generating waves it does use filters to listen to them and amplifier to be able to read the signal. Those amplifiers work regardless of the environment, such as a faraday. The box protects from accidental opening, but it shouldn’t affect battery life.

I do agree that 1min a day would be 6 hrs of activity per year, and it should shorten the life of the battery, in comparison to a “resting” key fob, but you should remember it is 6 hours out of 8,760 hours per year, where the key fob is listening intermittently all the time.

This is why you should expect the key that is used more often to dry its battery sooner than the “resting” one, just not a lot sooner.
My experience shows a couple of months difference, and I know several others with similar experience.

I hope this help clarify my previous posts
(and not further complicate them)

P.S. BTW, as I replace batteries in both key fob when one of them ends, I personally like to swap them every 3-6 months (the active with the resting one) this way I’m optimizing the time between battery swaps :-)

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6 minutes ago, AHG said:

Sorry for not elaborating.

When I wrote “all the time but not continuous” I meant it has a duty cycle (as all of these devices do, other no battery would ever last).

For example, if it listens for transmissions for 0.1sec out of every 0.5 second, so it is “24/7” just intermittently and not continuously (most electronics work like that).
In the example here there is a 20% duty cycle, which means the batter will last 5x more time than it would had it been listening continuously. It can be 10x or more.

I do not know if it is transmitting or just listening, as I wrote, and I do agree that transmitting takes up more energy than listening. But it is important to realize that energy is needed for listening as well, while although it is t generating waves it does use filters to listen to them and amplifier to be able to read the signal. Those amplifiers work regardless of the environment, such as a faraday. The box protects from accidental opening, but it shouldn’t affect battery life.

I do agree that 1min a day would be 6 hrs of activity per year, and it should shorten the life of the battery, in comparison to a “resting” key fob, but you should remember it is 6 hours out of 8,760 hours per year, where the key fob is listening intermittently all the time.

This is why you should expect the key that is used more often to dry its battery sooner than the “resting” one, just not a lot sooner.
My experience shows a couple of months difference, and I know several others with similar experience.

I hope this help clarify my previous posts
(and not further complicate them)

P.S. BTW, as I replace batteries in both key fob when one of them ends, I personally like to swap them every 3-6 months (the active with the resting one) this way I’m optimizing the time between battery swaps 🙂

@AHG
wow.

Boy.  
Does your R need to come soon.

😀

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1 hour ago, AHG said:

Sorry for not elaborating.

When I wrote “all the time but not continuous” I meant it has a duty cycle (as all of these devices do, other no battery would ever last).

For example, if it listens for transmissions for 0.1sec out of every 0.5 second, so it is “24/7” just intermittently and not continuously (most electronics work like that).
In the example here there is a 20% duty cycle, which means the batter will last 5x more time than it would had it been listening continuously. It can be 10x or more.

I do not know if it is transmitting or just listening, as I wrote, and I do agree that transmitting takes up more energy than listening. But it is important to realize that energy is needed for listening as well, while although it is t generating waves it does use filters to listen to them and amplifier to be able to read the signal. Those amplifiers work regardless of the environment, such as a faraday. The box protects from accidental opening, but it shouldn’t affect battery life.

I do agree that 1min a day would be 6 hrs of activity per year, and it should shorten the life of the battery, in comparison to a “resting” key fob, but you should remember it is 6 hours out of 8,760 hours per year, where the key fob is listening intermittently all the time.

This is why you should expect the key that is used more often to dry its battery sooner than the “resting” one, just not a lot sooner.
My experience shows a couple of months difference, and I know several others with similar experience.

I hope this help clarify my previous posts
(and not further complicate them)

P.S. BTW, as I replace batteries in both key fob when one of them ends, I personally like to swap them every 3-6 months (the active with the resting one) this way I’m optimizing the time between battery swaps 🙂

Hi AHG

 

Thanks for elaborating.

 

Yes, I am familiar with the “duty cycle” technique.

 

It is very common on all kinds of battery powered radio receivers to be only powered for a small part of every second, exactly how you suggest.

 

This saves battery and is fine where missing a split second of a transmission is not critical.

 

I am sure you are correct and the key fobs employ this technique as it would make perfect sense.

 

But, as your last post suggests, this is a technique for receivers, not transmitters, which is where I got confused as I thought your earlier posts were suggesting that the key fob is transmitting constantly regardless of where it is stored, which would kill the battery very quickly.

 

So, the bottom line is, I think we agree that a key that is never being used (and is stored out of range of the car) should last longer than a key that it constantly being used!

 

You say only 2 months longer, but the life of my used key was only approx 7 months, so that is almost 30% longer!!

 

My original point was only that the key that is never used should never have a flat battery at the same time (or before) the one that is used all the time. (unless the battery is faulty)

 

My R was not clearing the replace battery warning (unlike Rebecca’s that did) when I changed to the key which I had never used.

 

That was all I was trying to say.

 

Cheers

 

Jason

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I’m thinking of donating mine to this cause.  

Wheel is in the wrong side

BTW, I may get a chance to drive a right-wheeler car soon (thinking of a hop to Cyprus).
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