Actual Key Fob Data

[Steve181]

Being an Electrical Engineer I was curious about the key fob short life mystery, as it has hit me also. (New 2025 Air Pure). So I made some actual measurements

First, the Fob is made by a British Co. called Pektron. Their website has no Specs on it.

Next I took a microammeter and measured the current draw under the 3 conditions below:

1 - Qiesecent (far away from car): Very variable, changed about once per second in range from Approx 10 - 200 microamps.

2 - Pushing the button = 800 microamps.

3 - Sitting in car, with car on and in drive. Similar to #1 but seemed to peak at 400 microamps.

Let us reduce each of thse peaks by 1/2 to account for the duty cycle of the pulse in order to get an average draw. Thus, the averaege draw is about 100 - 200 microamps. More precise analysyis would require an oscilliscope.

The CR 2032 battery in the fob is rated at 225 mah = 225,000 micro-amp-hours. Thus, doing the simple math, at 200 microamp avearge draw it would last 47 days. At 100 microamp average draw it would last 94 days. At 50 microamp average draw it would last 188 days = 6 months. That is what many of us are noticing.

Conclusions:

1 - The fob must be scanning or has a high quiesent draw that is pulsed in some way to reduce average drain. A Farady shield is not going to fix this.
2 - None of my other cars have this problem. So better designs are possible.
3 - I am starting to think that Lucid owes us a new fob

A quick fix would be to add an external on-off slider switch in series with the battery.

Cheers,
Steve

 

[elin]

A Farady shield is not going to fix this.

My understanding of using a faraday pouch is for the scenario where the fob is near the car (and passive lock/unlock is enabled?)

I wonder if the energy usage of the fob is any different if passive unlock/lock is disabled (ie: car is asleep) and the fob is placed near the car.

 

[RM-S8]

I'd say, fob design is one of the weakest and most annoying adpects of owning Lucid. Hopefully, the Gravity will change that.

 

[Steve181]

I had previously disabled the Lucid feature that unlocks the car when the key is near. Also, measurement # 1 was taken very far from the car. The current shown was caused by a feature of the key itself.

I'm thinking about either a higher capacity battery or a switch in the case.

 

[Steve181]

Here some 'Rube Goldberg' type solutions I may try. A CR2 battery is larger (15.6 x 27 mm) but has a capacity of 850 mah, about 3.7 X that of the CR2032 in the Lucid key. That should give about 1 year of service. Just wire it in to the Lucid key in a larger leather key fob case. The CR123 battery is larger yet but has a 1400 mah capacity, over 6 times that of the Lucid battery. All in all, the Lucid key is streamlined and nice looking, but almost useless.

 

[Cosmo Cruz]

Steve 181: great post. thank you.

 

[DeaneG]

I had previously disabled the Lucid feature that unlocks the car when the key is near. Also, measurement # 1 was taken very far from the car. The current shown was caused by a feature of the key itself...

Some have said that the fob contains an accelerometer that wakes it from sleep when picked up, jiggled, etc. Quiescent consumption would supposedly be lower when the fob is at rest. I haven't cracked mine open to look for an accelerometer IC to see if this assertion is correct. This would likely not be contained on some other custom IC, as they require MEMS processing steps to fabricate.

 

[Halodde]

I'd say, fob design is one of the weakest and most annoying adpects of owning Lucid. Hopefully, the Gravity will change that.

I'm inclined to agree. My guess is that Lucid anticipated that the majority of owners would use the mobile key and not the fob. I'm not saying they cheaped out on the fob. But they may not have done as much as possible with the fob design because they didn't think it would get much use by a lot of owners.

Unfortunately, with the mobile key issues a lot of us have experienced, the fob is the go to for a lot of us.

 

[DeaneG]

...Unfortunately, with the mobile key issues a lot of us have experienced, the fob is the go to for a lot of us.

Yeah, my Pixel 9 mobile key has been flaky enough in a 2-week trial that I'll be switching back to the fob.

 

[Halodde]

Yeah, my Pixel 9 mobile key has been flaky enough that it's easier to use the fob.

Oh from what I read here, I thought the mobile key on pixel 9 was pretty good, no?

I should try it again with my S23 to see if it's any better after recent updates.

 

[DeaneG]

Oh from what I read here, I thought the mobile key on pixel 9 was pretty good, no?

I should try it again with my S23 to see if it's any better after recent updates.

That's why I thought I'd give it a try. It seems to be less reliable if I approach the car from behind, but I'm not sure.

 

[segbrk]

Here some 'Rube Goldberg' type solutions I may try. A CR2 battery is larger (15.6 x 27 mm) but has a capacity of 850 mah, about 3.7 X that of the CR2032 in the Lucid key. That should give about 1 year of service. Just wire it in to the Lucid key in a larger leather key fob case. The CR123 battery is larger yet but has a 1400 mah capacity, over 6 times that of the Lucid battery. All in all, the Lucid key is streamlined and nice looking, but almost useless.

Seems we had some similar ideas

Works great!
The performance actually seems better as well, not just the lifetime, I assume due to voltage drop in all the mostly-dead CR2032s.

 

[DeaneG]

Seems we had some similar ideas
View attachment 25961
Works great!
The performance actually seems better as well, not just the lifetime, I assume due to voltage drop in all the mostly-dead CR2032s.

And you won't lose it in your pocket!

 

[borski]

I'm inclined to agree. My guess is that Lucid anticipated that the majority of owners would use the mobile key and not the fob. I'm not saying they cheaped out on the fob. But they may not have done as much as possible with the fob design because they didn't think it would get much use by a lot of owners.

Unfortunately, with the mobile key issues a lot of us have experienced, the fob is the go to for a lot of us.

When Lucid was designing and building the Air, nobody know who they were. They didn’t “cheap out” as much as they were the “new guy at the bar” and nobody would pick up their calls. One company did. And I highly doubt they came cheap.

That is no longer the case today.

 

[Steve181]

I love that picture!!!! Thanks. I see at least 3 paths now:

1 - Live with it or use the mobile key. (Not for me.)

2 - Rube Goldberg. Fashion a new case or leather key case that would hold a CR2 or larger CR123. That method might include removing the electronics from the old Lucid key and putting it into the new shell or case - perhaps also including a proper new physical button. Are there any folks listening with access to 3D printing capabilities here? I'd glady pay $50 for a new shell.

3 - Pressuring Lucid for a proper key, including legal efforts. Are their any attorneys listening? Does the Gravity key solve this problem? It has nice needed physical buttons.

Every other car I have driven, including cheap barebones rentals, does not have this problem. I'm sure that Lucid could have found a key vendor to do a small run of generic keys with Lucid coding. Instead it appears that they picked a vendor that does high end stylish keys but ignored the power budget.

 

[thommev]

Keeping an eye on this thread. I have been sticking with mobile (S23) for 2 weeks of my ownership (25 Touring). It has worked decently so far (had to manually open with the app a couple of times because the car didnt detect it) even in midwest winter.

 

[DeaneG]

I honestly haven't had any problems with the fob. It's fine. I like it better than our Volvo fob, as Lucid's is much slimmer.

 

[Baumer55]

When Lucid was designing and building the Air, nobody know who they were. They didn’t “cheap out” as much as they were the “new guy at the bar” and nobody would pick up their calls. One company did. And I highly doubt they came cheap.

That is no longer the case today.

With respect to the mobile key, it is irritating that the contact point is located in the pillar at the side of the car by the front door and not the trunk. Whenever I want to open the trunk I have to go to the side of the car to activate the doors before the trunk will open. Hopefully this will be rectified in the future.

 

[Cosmo Cruz]

I love that picture!!!! Thanks.

needs no words. instant recognition and laugh-out-loud funny. I love the folk here.

 

[DeaneG]

With respect to the mobile key, it is irritating that the contact point is located in the pillar at the side of the car by the front door and not the trunk. Whenever I want to open the trunk I have to go to the side of the car to activate the doors before the trunk will open. Hopefully this will be rectified in the future.

I often click and hold the fob to open the trunk instead of walking to the side of the car, as I'm lazy and it's a long walk