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Key fob battery; spec and warning

RamShashi said:
I had similar issue. It is a common complaint I believe. Either you should keep the Key fob at least 25 feet away or put it in a metal box or wrap it up in a tin foil, with that the two way communication is prevented and the battery does not dry out.
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I have heard that wrapping in foil may act as an antennae, Just buy a faraday bag. Works great
 
RamShashi said:
I had similar issue. It is a common complaint I believe. Either you should keep the Key fob at least 25 feet away or put it in a metal box or wrap it up in a tin foil, with that the two way communication is prevented and the battery does not dry out.
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Also, make a tin foil hat and where it whenever you drive gravity to ensure good key reception. 🤣
 
Bill AGT said:
I have heard that wrapping in foil may act as an antennae, Just buy a faraday bag. Works great
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I'm honestly curious with this question. Nothing about saying you're wrong, I don't have the answer, just trying to dumb down my thoughts on this. I also don't have problems with my key, so this is purely for curiosity.

Does a faraday bag actually work? My understanding is both the car and they key "say hi" via RF and when they both "say hi" together the car unlocks. The key has to be in some state of motion (as I put in my other comment in this thread about having to jiggle my pocket) for it to start "saying hi". So if you put it in a faraday bag, why does the key then not transmit? Wouldn't it just be "saying hi" into the void waiting for a response? Or does the car initiate the response from the key?

For additional context, I'm a physical touch engineer. If I can see it or picture it, I can understand it. RF has, and always will be, black magic to me. "The waves moves like this at this frequency." Sure they do pal :D show me.
 
Spaceiscoolright said:
Does a faraday bag actually work? My understanding is both the car and they key "say hi" via RF and when they both "say hi" together the car unlocks. The key has to be in some state of motion (as I put in my other comment in this thread about having to jiggle my pocket) for it to start "saying hi". So if you put it in a faraday bag, why does the key then not transmit? Wouldn't it just be "saying hi" into the void waiting for a response? Or does the car initiate the response from the key?
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You're pretty much spot on here, and without knowing more about this particular system it's hard to say that isolating the key does anything helpful (except if you keep your key too close to the car and it's constantly active, if that's the way it works at all).

It appears that, as a battery saving measure, the key has a micromechanical sensor so that the RF portion is off unless there's been recent motion. So, at least theoretically, a still key should have very little power drain and RF-isolation should not be necessary. (Unless it's constantly "listening", but that's not consistent with putting in a MEMS sensor to begin with.)
 
Spaceiscoolright said:
Does a faraday bag actually work? My understanding is both the car and they key "say hi" via RF and when they both "say hi" together the car unlocks. The key has to be in some state of motion (as I put in my other comment in this thread about having to jiggle my pocket) for it to start "saying hi". So if you put it in a faraday bag, why does the key then not transmit? Wouldn't it just be "saying hi" into the void waiting for a response? Or does the car initiate the response from the key?
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I don't know who initiates the com but it doesn't really matter. Movement turns on the fob. The fob either or transmits or listens or both for a response to its id of interest for a set length of time. If it doesn't get a response soon enough or the response is too weak the fob shuts off.
 
Ron_Burgundy said:
Back in the day (c. 2013) the Model S fob ate batteries for some reason. Again, in 2016, our X did the same thing. Tesla must’ve done something at some point because after several months of ownership, batteries began to last for a year +. Of course, Tesla also used to give out the batteries for free…

So, I expect Lucid will figure it out.

Still not sure why someone doesn’t just make them rechargeable. Too many cycles over the life of the car? Feels like an easy thing to do except charging standards could change over life of ownership.
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Wireless charging in the car!
 
jrreno said:
Wireless charging in the car!
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Volvo and Polestar do this. I'd rather not take the fob out of my pocket though. Too great a chance I'd forget it in the car.
 
Spaceiscoolright said:
I'm honestly curious with this question. Nothing about saying you're wrong, I don't have the answer, just trying to dumb down my thoughts on this. I also don't have problems with my key, so this is purely for curiosity.

Does a faraday bag actually work? My understanding is both the car and they key "say hi" via RF and when they both "say hi" together the car unlocks. The key has to be in some state of motion (as I put in my other comment in this thread about having to jiggle my pocket) for it to start "saying hi". So if you put it in a faraday bag, why does the key then not transmit? Wouldn't it just be "saying hi" into the void waiting for a response? Or does the car initiate the response from the key?

For additional context, I'm a physical touch engineer. If I can see it or picture it, I can understand it. RF has, and always will be, black magic to me. "The waves moves like this at this frequency." Sure they do pal :D show me.
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With Air (and I'm assuming Gravity), the problem is the key fob and/or mobile key communicate with the car from much further away than they unlock. They say hi, then they figure out how far away they are from each other before unlocking. So if your fob is far from your car, nothing is happening until you wiggle it, you're fine. If your fob is sitting in your entryway bin with your keys and wallet 20 feet from your car, it's regularly saying "are we close together yet? are we? are we? how about now?" It's not unlocking, but it is talking and draining its battery.
 
DeaneG said:
Volvo and Polestar do this. I'd rather not take the fob out of my pocket though. Too great a chance I'd forget it in the car.
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CR 2477 Battery inside cheap fake leather key case from Amazon. Almost 5 months now. No Faraday bag. Passive unlock off.
 

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A fob is just outdated for these cars at this point. PaaK is standard and expected for EV only manufacturers.

That said, I will, of course, deal with the fob knowing PaaK is coming. But my gosh darn fob has yet to work to start the car for more than a week. Brutal. But early adopter syndrome. It will be fine.
 
Ron_Burgundy said:
Hmmm. I think our 2022 X fob still has a battery. How would it charge in the car?
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Some models have a dedicated fob charging spot. In others, you place the fob on the phone charging area.
 
DeaneG said:
Some models have a dedicated fob charging spot. In others, you place the fob on the phone charging area.
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Guess we missed that. Our X wireless charging pads rarely work. Have to be very precise with placement.

I DO think that type of tech is much better than old school batteries.
 
Ron_Burgundy said:
A fob is just outdated for these cars at this point. PaaK is standard and expected for EV only manufacturers.

That said, I will, of course, deal with the fob knowing PaaK is coming. But my gosh darn fob has yet to work to start the car for more than a week. Brutal. But early adopter syndrome. It will be fine.
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You SHUT YO MOUTH! #FOB4LIFE
 
Ron_Burgundy said:
...I DO think that type of tech is much better than old school batteries.
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You'd think so, but there are complaints about it on Polestar forums!
 
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