Key Fob Battery Life after Update to latest firmware

[bicycleguy]

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.

Well pooh. Now you reminded me of something I forgot to check and even forgot to mention that I had auto lock enabled. I'll use the same methods as above so it should be comparable. I won't even venture a guess at this point.

Curious if you tried to see what scenario you might be in. Do I need to explain a little bit more about how that is calculated?

 

[illopp00]

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.

Is 600mah a common CR2032 battery they have been shipping the Fobs with? I have seen mostly 220mah ones readily available?

 

[illopp00]

And then I guess the one other experiment is does it behave worse once the battery is drained under 3V...

 

[RandomDesign]

Is 600mah a common CR2032 battery they have been shipping the Fobs with? I have seen mostly 220mah ones readily available?

The Gravity fob uses a CR2450 instead of the 2032 that's used in the Air and 2450s are commonly around 600mAh.

 

[bicycleguy]

And then I guess the one other experiment is does it behave worse once the battery is drained under 3V...

The battery is nearly always under 3v.
It's hard to relate to the 'softness' of lithium dioxide batteries. They are analogous to a feather bed. Just a little pressure and they drop down. Push harder and they drop deeper but take the load off and they quickly at first and then more slowly spring back to nearly the start voltage. That's why people think they solved all their problems by removing and replacing the same battery, just postponing the inevitable.
I have measured the fobs current down to ~2.55V where they stop working and or crash. That is using a power supply, not a lithium battery. It's likely worse(higher) with the battery. Interestingly the current goes up as the voltage goes down till that point indicating some kind of regulation in action. A lot is going on in that little fob.

 

[VLumina]

Is the number of hours different for "asleep but within range"? Or is that not a valid state?

 

[bicycleguy]

Is the number of hours different for "asleep but within range"? Or is that not a valid state?

sleep within range, outside of range or in a faraday bag is the same. That's why I no longer use a faraday bag. It's what happens when you wake it that changes. I guess the exception would be sleep in a faraday bag in the car which might be problematic for the car, but as far as the fob is concerned is the same as regular sleep. Note that normal sleep in the car is a little higher than sleep within range, but lower than awake, because the car knows the fob is in the car and the doors are locked and you selected D or R and so does less communication with it(specifically with 2.35.08 to save the battery).

 

[DrK]

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

Happening to me too. Started a week ago. Swapped to new fob battery ( (kept in car) then behavior on. Two days later happening again. Battery at rest out of range>30 minutes: voltage 2.9v. But in car I did not have voltmeter to check voltage out in it’s wrapper before using . Ie incomplete analysis. So now putting voltmeter in glove box! ( curious: what do people put in this low profile but deep and large glove box?)

 

[tmichael]

There is a known issue with a batch of key fobs, but they have to be replaced by service (center or mobile). If you have two fobs, they have to have both together at the same time.

Mine will be handled by mobile next time they are out.

 

[bicycleguy]

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.

Just went through my little test suite again with the auto lock/unlock turned off. From the fob power consumption side it is identical to when turned on. The car of course acts a little differently. With auto lock on whatever the car does to get ready starts when your about 20feet from the car and takes maybe 1 to 4 seconds to turn on the trim lights and make various buzzing and clicks. The doors unlock when within a foot. With auto lock off that startup sequence doesn't happen until you hit the button and may take a few seconds to unlock whether you push the button again or not so it seems more laggy. Again though, whatever the car is doing doesn't seem to affect the fob.

While doing this experiment I discovered a mistake in what it takes to make the fob sleep in the car. I thought you had to put in D or R and wait ~60 seconds. Unbelievably you have to physically move the car about 10ft after the doors auto lock. There may be some other trick to make it happen but I can't seem to find it. The fob returns to awake mode as soon as you unlock or open a door. Unfortunately for @Ron_Burgundy who posted somewhere about dropping the kids off and sitting listening to tunes I don't know of a way to make the fob sleep without moving the car ~10ft or using the dreaded faraday bag.

 

[bicycleguy]

The fob returns to awake mode as soon as you unlock or open a door. Unfortunately for @Ron_Burgundy who posted somewhere about dropping the kids off and sitting listening to tunes I don't know of a way to make the fob sleep without moving the car ~10ft or using the dreaded faraday bag.

Sorry, the fob does not awake on door unlock, only opening a door. Also if you use the faraday bag you risk locking the fob in the car if you have no key card because the handle push won't unlock it if car senses no fob in car.

 

[tmichael]

There is a known issue with a batch of key fobs, but they have to be replaced by service (center or mobile). If you have two fobs, they have to have both together at the same time.

Mine will be handled by mobile next time they are out.

By the way, this batch is unrelated to the buttons falling out - software-oriented batch...

 

[FoggyStar]

Mine improved after I re-paired the fob in the car settings and turned off passive entry for a day. After that, the battery started lasting a couple of weeks again.

 

[mikehenry]

Happening to me too. Started a week ago. Swapped to new fob battery ( (kept in car) then behavior on. Two days later happening again. Battery at rest out of range>30 minutes: voltage 2.9v. But in car I did not have voltmeter to check voltage out in it’s wrapper before using . Ie incomplete analysis. So now putting voltmeter in glove box! ( curious: what do people put in this low profile but deep and large glove box?)

I’m dealing with this right now as well. Replaced my battery a week ago (my voltage tester was of the less precise variety but was still in the “green zone”). New battery, not even two days later isn’t being recognized (though it often unlocks the car with proximity!).

I bought a faraday bag for my house. It really feels like overkill but I’m getting tired of this. (Car is 4m3.3.1 and fob is 2.35.08)

 

[bicycleguy]

I’m dealing with this right now as well. Replaced my battery a week ago (my voltage tester was of the less precise variety but was still in the “green zone”). New battery, not even two days later isn’t being recognized (though it often unlocks the car with proximity!).

I bought a faraday bag for my house. It really feels like overkill but I’m getting tired of this. (Car is 4m3.3.1 and fob is 2.35.08)

Not sure what 4m3.3.1 is. The car should be ver 3.4.0 or 3.4.1 with fob 2.35.08.
fob version 2.35.08 really caused excessive drain for those of us who updated to it before the car was updated to 3.4.x

Some of the cheap 'green zone' type battery testers can be pretty good if they are setup for the size CR2450 and battery type Lithium dioxide. That is because they internally put an appropriate load on the battery while testing. As mentioned #47 above because of how the voltage drops on load and recovers in minutes to days the best time to test the battery is immediately after having used it for a while or after it fails to work. You want to test it at its worst state. If you wait 10 minutes it can easily gain .15V

 

[mikehenry]

Not sure what 4m3.3.1 is. The car should be ver 3.4.0 or 3.4.1 with fob 2.35.08.

It’s me typing poorly on my phone and not spellchecking. Should have read 3.4.1.

 

[bicycleguy]

Bumping this post as the name says "... Latest Firmware" and now we have 3.5.1

I haven't gotten a chance to see if 3.5.1 had any effect on the fob battery currents yet but I do have a new state to add to the chart in post #35. This morning after a few trouble free days with 3.5.1 the car would not respond at all to the fob. I immediately measured the fob voltage to be 3.0205V which should have been more than high enough to work. Previously when the fob was crashed the voltage was down below 2.8V and draining at a high rate. So the fob can quit working without draining the battery. Put the battery back in the fob and went to the car and all was normal again.

The phone app would have worked so maybe I should give up looking at this. But I'm still curious. By the way I'm on day 51 with a battery from the visor which measured 3.05V on day zero.

 

[bicycleguy]

Bumping this post as the name says "... Latest Firmware" and now we have 3.6.0

3.6.0 doesn't seem to have changed the fob battery consumption much even thought the range to car lighting up and range to car unlocking have changed for me by ~5 feet. So most of what I posted in post #35 still applies.

One thing I did notice but can't verify(because Ive updated) is that with 3.5.1 you needed to move the car about 10 feet to make the fob sleep in the car even with movement. Now it seems to be that you need to go at least 5mph, either forward or back. I tested to about 50ft going less and fob didn't sleep. Here's some data for those interested.

Time.........What's Happening
35.............Picked up fob.
35-210.....Lots going on of little consequence, getting within ~40ft, car waking, unlocking, opening, all unrelated to the current bumps seen and all high consumption regardless.
210...........~5mph backing out driveway(don't try this with wife).
210-515...Driving around block. Little bumps are the fob getting jiggled, then shutting down.
515...........Unlocking the door and getting out.
590...........60 seconds after putting the fob down.

Note the green Voltage line, the fob voltage drops like crazy when under load and recovers gradually when not. This is about a month into a battery from the visor.

 

[socktucker]

Bumping this post as the name says "... Latest Firmware" and now we have 3.6.0

3.6.0 doesn't seem to have changed the fob battery consumption much even thought the range to car lighting up and range to car unlocking have changed for me by ~5 feet. So most of what I posted in post #35 still applies.

One thing I did notice but can't verify(because Ive updated) is that with 3.5.1 you needed to move the car about 10 feet to make the fob sleep in the car even with movement. Now it seems to be that you need to go at least 5mph, either forward or back. I tested to about 50ft going less and fob didn't sleep. Here's some data for those interested.

View attachment 39285
Time.........What's Happening
35.............Picked up fob.
35-210.....Lots going on of little consequence, getting within ~40ft, car waking, unlocking, opening, all unrelated to the current bumps seen and all high consumption regardless.
210...........~5mph backing out driveway(don't try this with wife).
210-515...Driving around block. Little bumps are the fob getting jiggled, then shutting down.
515...........Unlocking the door and getting out.
590...........60 seconds after putting the fob down.

Note the green Voltage line, the fob voltage drops like crazy when under load and recovers gradually when not. This is about a month into a battery from the visor.

I feel as dumb as @borski thinks I am when I try to read this

 

[bicycleguy]

I feel as dumb as @borski thinks I am when I try to read this

Your management material ! buck up fire me!

EDIT: Sorry, can't get the Emad news out of my mind.