Key Fob Battery Life after Update to latest firmware

[brokebit4096]

I’m still on my original battery at 7 weeks and counting. Five weeks on 3.3.20 and two weeks on 3.4.1.

I’ve kept the key fob in my pants pocket continuously, including on daily walks with my dog.

When you are hanging out at home, how far are you from your car?

 

[brokebit4096]

Here's my bandaid solution to the faraday box:
BAND-AID Brand Anniversary Tin edition

By the way since 3.4.1 and 2.35.08 I don't need it any more. As long as I don't jostle the fob the consumption is the same as faraday box even with auto lock/unlock enabled. My latest testing was to determine how much movement caused the fob to wake up.

Any time you do one of the following the fob will wake up for at least ~60 seconds. (what that means later, woke is not all that bad !)
1. Try to pick it up as carefully as possible.
2. Put the fob in your pocket and try to walk.
3. With the fob sleeping in your pocket because you stood there motionless for sixty seconds, try to start walking.
4. With the fob on the table pound once like Cozmo in Moon Struck.
5. Remove and reinstall the battery, even if done without jostling.
6. Almost forgot, press any key of course!

Band aid tin, very practical. I'm curious about your 3d battery jig. Could you share a close-up photo or STL?

 

[someguy]

My remote wasn’t working well a few weeks ago and I just removed the battery and waited 10-20 seconds about it back in. That solved my problem. I’d suggest trying that before replacing the battery.

 

[borski]

Maybve I'm taking this too far:

View attachment 36829
View attachment 36826

So, I did some basic power analysis on the keyfob. When it's "awake," and the car is about 40ft away, it seems to ping once a second. When it does that, it draws up to 48mA.

View attachment 36827

After about one minute, it seems to go to sleep. At which point I see spikes of current draw of about 9mA on average every one to two seconds.

View attachment 36828

On the spectrum analyzer, you can clearly see a beacon every second when the key is awake, right at 2.4Ghz. So, that is probably some sort of Bluetooth beaconing. I looked up the FCC ID for the fob, and it appears to support ultra-wideband communications at 6.5 GHz, 7.5 GHz, and 8.5 GHz. I should have some time next week to try to analyze that and see if there is any TX on those bands when it's sleeping. The next step is to do the same analysis on my Subaru fob, which seems to last forever.

I also noticed it does not take much to "wake" the key. Simply tapping on my desk was enough to wake it.

I let the fob sit for an hour and tracked its power consumption. Based on that, it should last years. (~70 µWh per hours sleeping) So, at some point, when I'm not looking, something is draining the battery.
View attachment 36830

I've also watched when the car wasn't home, and it doesn't seem to matter. The pattern is the same. This is with the latest firmware on the fob and car.

My battery seems to die within 7 to 10 days.

Thank you for the great analysis!

 

[borski]

Great work!

But, shouldn't Lucid have already done all these analyses?

I’m certain they have.

It is particularly sad and unforgivable given similar experience on the Air FOB. In the Air-case, Lucid placed the blame on the FOB manufacturer and cited a contract they couldn't get out of with the FOB manufacturer. Honestly, that sounded like a crock of SH*T!

It wasn’t.

Is Lucid management dealing withs customers on the up-and-up?!

Yes.

To me, the locking/unlocking problems is the #1 safety concern. I will not let my family or friends drive the Lucid alone in fear they might get stranded somewhere in the middle of the night and can't get in the car.

Am I exaggerating? Nope, that happened to me one month I got my Lucid air, in December 2022.

It’s been quite a long time since then. You might consider that things have changed in over 3 years.

 

[Saksak]

When you are hanging out at home, how far are you from your car?

Anywhere from 25 ft to 50 ft. The Gravity is the farther car in our two-car garage. I notice the car doors lock and the Gravity goes to sleep before I make it around our other car and into the house. I don’t think my key fob is continually waking up the car while I’m in the house, but I am moving around with the key fob in my pocket.

 

[Hammerthyme]

Just weighing in. We got the Gravity on 12/23 and once at the end of December had the fob not work. We had to use the cardkey as a workaround. I updated to v3.3.20 plus the keyfob upgrade and replaced the supplied Malak brand battery in the keyfob with an Energizer.CR2450. I have not had any errors since and have updated to 3.4.1 with plus the keyfob upgrade when it came out. I pulled the keyfob battery and put it back in, to make sure the software was properly loaded. The battery has still been running after 6 weeks.

We run with auto lock and unlock active and the keyfob reliably works when we walk within about 4 feet of the car. Battery life might be helped by the fact that we have a detached garage with two brick walls between car and key. We also keep the keyfob on our key rack when we are at home, so it doesn't get jostled around a lot.

Not sure if any of that will help with troubleshooting, but this is what we do and have had near zero problems with the keyfob since pre-3.3.20.

 

[doubletwist]

Agreed. My wife got stranded the other night, and I had to go pick her up. For now, she is keeping one of the RFID cards in her purse as plan B. I suspect Lucid is in a bind with the mfg of these fobs and can't easily switch out. Hopefully, they can get the phone key stuff working on the gravity. I used to have a Tesla, and the phone key was great. I never thought about locking / unlocking.

I thought the key fobs were supposed to work as RFID even when the battery was dead??

 

[Adnillien]

I thought the key fobs were supposed to work as RFID even when the battery was dead??

They do on the Air but not yet on Gravity.

 

[Saksak]

My key fob lasted

I’m still on my original battery at 7 weeks and counting. Five weeks on 3.3.20 and two weeks on 3.4.1.

I’ve kept the key fob in my pants pocket continuously, including on daily walks with my dog.

Update: My battery lasted 7.5 weeks. I also verified the key fob RFID does not work; carrying the key card as backup is mandatory.

I started suspecting a low battery this morning. I had to get closer than usual to my Gravity for it to open. I just got a low battery warning tonight and replaced it.

Let’s see how long this one lasts purely on 3.4.1+2.35.08.

 

[Bus Driver]

I haven’t replaced my key fob battery at all. I’ve had my Gravity since late December 2025. The key fob has always worked to unlock my car. Perhaps the only change I’ve noticed in the last few weeks is that the car takes a “long time” to kill the lights and lock the doors after I walk away.

 

[Hammerthyme]

... the car takes a “long time” to kill the lights and lock the doors after I walk away.

This is the thing that took us the longest to get used to. You just get up and leave it running there with its lights on and the music playing. We have auto lock and unlock on, so it's pretty good about shutting down when we are a few feet away, but we still look back to check on it.

On a related note, I was wondering about key card usage and called Customer Care for an explanation. Apparently, if you use your key card on the B pillar sensor to unlock the car you should do the same to lock it when you are leaving. Then it may take "up to 5 minutes" for the car to go into sleep mode. I wasn't expecting that, since we usually use the key fob auto lock, and thought something was wrong.

 

[Cdaorl]

After latest updates (Keys and Gravity) , everything with wireless keys included, was working fine. One week ago the vehicle does not recognize either keys when approaching , but neither manual commands. I can only enter using my card. Lucid told me may need in person service since none of the usual tricks worked ( new battery, etc) . I am wondering if anyone else had this issue and how was fixed. thanks

 

[RandomDesign]

After latest updates (Keys and Gravity) , everything with wireless keys included, was working fine. One week ago the vehicle does not recognize either keys when approaching , but neither manual commands. I can only enter using my card. Lucid told me may need in person service since none of the usual tricks worked ( new battery, etc) . I am wondering if anyone else had this issue and how was fixed. thanks

Sounds like what @Klinkman had happening here: https://lucidowners.com/threads/lucid-gravity-3-4-0-software-update.14846/post-329610

 

[bicycleguy]

This is a summary of fob battery current data using car ver 3.4.1 and fob 2.35.08. Basically there appear to be four distinct power consumption states as listed in column 1. Drain values are the highest of two different measuring techniques.

FOB Power Usage States	Drain(uA)	Battery Life assuming 600mAh battery (Hours)
sleep, outside of car any distance, no fob movement for > ~60 seconds.	42	14286
awake, out of range (>50ft), nearly any fob movement	170	3529
sleep, inside car after 1 minute of D or R 1st selected even if further movement	200	3000
awake anywhere in range, for 1 minute after movement	3800	158

To get an idea what that means column 3 shows how long the battery would last in hours if continuously on in that state. So if the fob was asleep you could calculate from the battery capacity and drain the life would be:
600mAh/42uA * 1000uA/1mA = 14285 hours or *1day/24hours = 595 days

More interesting would be to look at some typical usages:

Note the EV race scenario would have been about 7 days with the last revision.

 

[brokebit4096]

This is a summary of fob battery current data using car ver 3.4.1 and fob 2.35.08. Basically there appear to be four distinct power consumption states as listed in column 1. Drain values are the highest of two different measuring techniques.

FOB Power Usage States	Drain(uA)	Battery Life assuming 600mAh battery (Hours)
sleep, outside of car any distance, no fob movement for > ~60 seconds.	42	14286
awake, out of range (>50ft), nearly any fob movement	170	3529
sleep, inside car after 1 minute of D or R 1st selected even if further movement	200	3000
awake anywhere in range, for 1 minute after movement	3800	158

To get an idea what that means column 3 shows how long the battery would last in hours if continuously on in that state. So if the fob was asleep you could calculate from the battery capacity and drain the life would be:
600mAh/42uA * 1000uA/1mA = 14285 hours or *1day/24hours = 595 days

More interesting would be to look at some typical usages:
View attachment 36902

View attachment 36903

Note the EV race scenario would have been about 7 days with the last revision.

I love your approach to the analysis. I think we were inadvertently in scenario 6. My wife would leave the fob in her purse, which hangs on the back of her office chair. She’s moving and rolling around on the chair throughout the day, which constantly wakes the key up. The car is close enough to be in range, too. She then probably averages 2-3 short trips per day. The predicted life span is also consistent with our experience.

I’m really curious how our Subaru fob handled this, since she kept it in her purse on the chair, too, and we didn’t have any battery issues. I’d say on average, a battery in the Subaru fob lasted 9 - 12 months.

Starting last Thursday, we started keeping the fob in a Faraday box on a shelf near the door. It’s too soon to see if that’s helped, but that should be the equivalent of scenario 1.

 

[bicycleguy]

This is a summary of fob battery current data using car ver 3.4.1 and fob 2.35.08. Basically there appear to be four distinct power consumption states as listed in column 1.

I forgot to note one other elusive state that I did see on a few occasions:
crashed 3000uA 200 hours or about 8 days.

In the crashed state some kind of continuous loop was happening that shaking or button presses had no effect on. The crashed state seemed to happen after a lot of 'awake in range' and button pressing probably lowering the battery voltage. I didn't wait much longer more than the usual 60seconds to see if it would stop but removing the battery was effective.

.....
I’m really curious how our Subaru fob handled this, since she kept it in her purse on the chair, too, and we didn’t have any battery issues. I’d say on average, a battery in the Subaru fob lasted 9 - 12 months.

Starting last Thursday, we started keeping the fob in a Faraday box on a shelf near the door. It’s too soon to see if that’s helped, but that should be the equivalent of scenario 1.

Not sure about your Subaru fob but old school fobs didn't turn on till you pressed a button and they were transmitters only. This fob is never truly off. 'Sleep mode' is close with nearly 2 year battery life. However sleep mode is very sensitive to any movement and if detected then starts sending out a signal every second for about a minute after the last movement. If the vehicle is in range it sends a signal to the fob. So the fob also has a receiver. If the fob receives a signal from the car then they start blabbing with each other until one of them decides to shut up. All this happens with no human detectable reaction from car or fob.

All this complication is so you can walk up to the car and have it open automatically in a secure way.

I think I would much rather have an embedded real ON/OFF slide switch on the fob so I could determine when I wanted this complication.

 

[borski]

I’m really curious how our Subaru fob handled this, since she kept it in her purse on the chair, too, and we didn’t have any battery issues. I’d say on average, a battery in the Subaru fob lasted 9 - 12 months.

It didn't use Bluetooth/UWB. It used radio. Lower power needs, higher security risks, lots of other pros/cons.

 

[RandomDesign]

I'm curious how turning off the auto lock/unlock setting in the car would change the battery longevity. I'm still using the battery I put in the fob on 12/19 (a Retail Digitals brand 610mAh from Amazon) to replace the one it had when I took delivery that day knowing the stock ones died fast. I do keep it in a known good faraday box too.

I don't use the auto unlock right now and just use the fob as a fob to manually lock/unlock the Gravity, I haven't pulled it out lately to test it on the multimeter though and should do that.

 

[Gravitas]

I'm curious how turning off the auto lock/unlock setting in the car would change the battery longevity. I'm still using the battery I put in the fob on 12/19 (a Retail Digitals brand 610mAh from Amazon) to replace the one it had when I took delivery that day knowing the stock ones died fast. I do keep it in a known good faraday box too.

I don't use the auto unlock right now and just use the fob as a fob to manually lock/unlock the Gravity, I haven't pulled it out lately to test it on the multimeter though and should do that.

I've always used Auto Lock/Unlock with same battery delivered on same day as you, 12/19/2025.
Granted, I was away on vacation for 10 days around Christmas/New Year.
I don't use a Faraday box.