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P100D X 12V battery dying in a car without any warning?

turtlesz

Member
Aug 7, 2017
520
498
Southern California
Today our P100D X would not turn on and power doors are not working and headlights would flash erratically. Lots of error messages would flash sporadically and ultimately the screen would not turn on. App still worked and car had 240 miles of charge. Had been using the car without issue and it happened suddenly when trying to get in the car in the morning. My car was not just sitting idly for days and was driven regularly and charged. Attached a picture of some of the error messages that have been popping up. Mobile service said they would replace the 12v which may likely fix issue rather then tow to service center. Hope its just the battery but I'm just concerned it may be something bigger especially since we have a Yosemite trip planned. Its concerning that these 12V batteries can die so quickly without warning and can leave drivers stranded easily. We use our 3 and X to roadtrip frequently and the thought of having a 12V battery as a ticking time bomb causes significant concern when planning for a trip now.

Seems like it might be a widespread issue and there is a thread of 12V batteries dying in cars 2 years and under. Hope they can implement a fix for this issue of the 12V, maybe allow the main battery to take over the function of the 12V temporarily? https://teslamotorsclub.com/tmc/threads/12v-battery-must-be-replaced-soon.203397/

Tesla's are fun and all but our experience between 4 different Tesla's in the family is that they have not been very dependable which has required us to keep a spare ICE around. Hope that they continue to get more reliable. When they are working as they should they are the most fun things to drive though.

Our Model 3 LR RWD from March 2018 - 2 drive unit failures requiring a tow, 1 of those failures was while the car was driving and died and the other was after a supercharging session. Posted on this a while back https://teslamotorsclub.com/tmc/thr...wer-reduced-error-after-supercharging.135972/

Family members LR RWD 3 - battery unable to charge and eventually required a new battery pack.

Family members X 75D - AC compressor died with 8k miles

Our P100D X - won't start, lots of error messages. Possible 12V battery died without warning
 

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animorph

Active Member
Apr 1, 2016
2,152
1,580
Scottsdale, AZ
Most of the recent battery replacement problems have been with the Model 3. We just had that with our 3 (Sept 2018). No warning, car acts like the MCU is malfunctioning. We drove it to the Service Center and they kindly replaced the battery immediately.

My X finally gave me a battery warning after 3.5 years in Arizona, which is not a terrible battery life here in the heat. Most X's and S's have been giving an early battery warning that still gives you a couple of weeks to replace the battery. Other than occasional posts here, that seems to still be holding true, for X and S. I didn't get a chance to test that two weeks since the X is not being driven regularly at this time.

I went ahead and bought an ohmmu 12V lithium battery for the X, but I haven't heard of any of them being in service for four or more years yet to see how they last.
 

rjdoc74

Member
Feb 27, 2014
928
726
LA, CA
My 2018 P100D 12v battery warning came on this past Thursday and SC mobile tech replaced it on Friday. While tech was working on the car I asked about these batteries and was told they last 2-2.5 years MAX.
 

crazymatt

Member
Jul 2, 2018
15
13
Utah
2018 75d had a similar issue earlier this year. Went to pick up food from restaurant. Came back out and 12v was gone. Got it towed. Had to get Uber home with food. I didn’t get a warning. Don’t remember what service center said besides it happens.
 

scottf200

Active Member
Feb 3, 2013
4,231
4,078
Chicagoland ModelX S603
Is there a better verification option than IR/Internal Resistance?

How to distinguish between good and bad 12V lead acid batteries with the internal resistance value - Quora
In a Lead Acid Battery, the lower the battery internal resistance the more the battery in good condition.
To be exact, for a 12V LA Battery,
* If IR > 30 milliohm, battery is in very bad condition. Probably unusable.
* If IR is between 10 to 30 milliohm, still poor condition but may be usable or revivable.
* If IR is between 5 to 10 milliohm, it is in good condition.
* If IR is less than 5 milliohm, it is in very good condition.

But all this given criteria are just an estimate and does not guarantee the battery condition. As the condition depends upon some other factors too.
Rising Internal Resistance - Battery University
Measured in milliohms (mΩ), resistance is the gatekeeper of the battery; the lower the resistance, the less restriction the pack encounters.

A battery with low internal resistance delivers high current on demand. High resistance causes the battery to heat up and the voltage to drop. The equipment cuts off, leaving energy behind.
 

turtlesz

Member
Aug 7, 2017
520
498
Southern California
2018 75d had a similar issue earlier this year. Went to pick up food from restaurant. Came back out and 12v was gone. Got it towed. Had to get Uber home with food. I didn’t get a warning. Don’t remember what service center said besides it happens.

Thats frustrating when this happens if your out of the home. Sadly no mobile service has been able to be reached by the roadside assistance side and now they are telling me the car will have to be towed to a nearby service center. They didn't mention any alternative forms of transportation or loaner that could be provided. They really need to step up their service game as this is pretty unacceptable especially for a fully loaded vehicle thats supposed to be their current flagship.
 

dailo

Member
Jul 22, 2017
748
848
Bay Area
If one had a portable battery jumper, would it be enough to start the car and keep it using so you can drive off? Wondering if you could just leave it connected to the battery and if that would be enough to get one back home? Luckily I got the warning and getting it replaced right now, but just curious what options I would have if I was on a road trip.
 

jboy210

Supporting Member
Supporting Member
Dec 2, 2016
5,517
3,507
Northern California

r0xx0r

Member
Jul 9, 2016
438
356
CA
Since it is 3 or more years old why not just replace it? I used to replace my BMW batteries at 3 years and never experienced an on the road battery failure.
Weeee you need an evidence of a failure 12V to get it replaced for free. Otherwise, it would cost you $500+.

My 2017 X 75D had to replace the 12V twice. The first one lasted ... 1y old. The second battery popped the “12V battery must be replaced soon/Software updates will not complete until serviced” few weeks ago. So it lasted 2y.
 

jboy210

Supporting Member
Supporting Member
Dec 2, 2016
5,517
3,507
Northern California
Weeee you need an evidence of a failure 12V to get it replaced for free. Otherwise, it would cost you $500+.

My 2017 X 75D had to replace the 12V twice. The first one lasted ... 1y old. The second battery popped the “12V battery must be replaced soon/Software updates will not complete until serviced” few weeks ago. So it lasted 2y.

$500 is easily eaten up at one on the road breakdown with an extra nights hotel stay, towing, etc. I paid for each one of those $500 BMW battery replacements and registrations myself to avoid these hassles.
 
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scottf200

Active Member
Feb 3, 2013
4,231
4,078
Chicagoland ModelX S603

I feel like my original 12V in my 2017 MX is a ticking time bomb. Anything that I can do to check its health?
Do these things work?
https://www.amazon.com/gp/product/B...&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee
My post above about IR was related to videos like this one and the information I pointed to about Internal Resistance being a real indicator (scale in my prev post).
 
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scottf200

Active Member
Feb 3, 2013
4,231
4,078
Chicagoland ModelX S603
There are several battery testers that give you IR. I just ended up doing some research and bought this one (Ancel BA101).
Tesla 12v battery info: 12 Volt Battery Compendium | TeslaTap
Going to test my 2017 X in a few days when it gets here:

OVpoQQM.jpg


gjUgr5I.jpg

* If IR > 30 milliohm, battery is in very bad condition. Probably unusable.
* If IR is between 10 to 30 milliohm, still poor condition but may be usable or revivable.
* If IR is between 5 to 10 milliohm, it is in good condition.
* If IR is less than 5 milliohm, it is in very good condition.
 

VikH

Supporting Member
Supporting Member
Nov 23, 2015
1,083
1,025
Midwest, USA
There are several battery testers that give you IR. I just ended up doing some research and bought this one (Ancel BA101).
Tesla 12v battery info: 12 Volt Battery Compendium | TeslaTap
Going to test my 2017 X in a few days when it gets here:

OVpoQQM.jpg


gjUgr5I.jpg

* If IR > 30 milliohm, battery is in very bad condition. Probably unusable.
* If IR is between 10 to 30 milliohm, still poor condition but may be usable or revivable.
* If IR is between 5 to 10 milliohm, it is in good condition.
* If IR is less than 5 milliohm, it is in very good condition.

Thanks. Just ordered one too. Can you post here with your results? I have a June 2017 build Model X with 30k miles. I will do the same.
 
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Solarman004

Member
Apr 27, 2016
770
1,031
Colorado
I feel like my original 12V in my 2017 MX is a ticking time bomb. Anything that I can do to check its health?

Do these things work?

https://www.amazon.com/gp/product/B...&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee

Our MX is a 2016 with 56,000 miles. I had the frunk tub out to disconnect the battery for an eMMC card replacement, and decided to preemptively change out the battery. I got it tested at an auto parts store, and it tested as "marginal" so I'm glad I made the swap. I am holding on to it as a spare.
The only frustrating part of this process was the inability to find this battery at any auto parts store. I had to make a 1 hour drive to the Denver SC to pick it up, but at least they had them in stock.
 

scottf200

Active Member
Feb 3, 2013
4,231
4,078
Chicagoland ModelX S603
Our MX is a 2016 with 56,000 miles. I had the frunk tub out to disconnect the battery for an eMMC card replacement, and decided to preemptively change out the battery. I got it tested at an auto parts store, and it tested as "marginal" so I'm glad I made the swap. I am holding on to it as a spare.
The only frustrating part of this process was the inability to find this battery at any auto parts store. I had to make a 1 hour drive to the Denver SC to pick it up, but at least they had them in stock.
Did you do steps 5 & 6 below (service manual)? A YT video I saw they just did the menu 'Power Off' option but I know that doesn't shut everything down based on my monitoring the car with Scan My Tesla app and BT connection.

uvwzVF6.jpg
 

Solarman004

Member
Apr 27, 2016
770
1,031
Colorado
Did you do steps 5 & 6 below (service manual)? A YT video I saw they just did the menu 'Power Off' option but I know that doesn't shut everything down based on my monitoring the car with Scan My Tesla app and BT connection.

uvwzVF6.jpg
Yes. I did remove the first responder loop. It's a very easy connector to remove by depressing tabs on each side. The process is reversed for bringing the car back up: loop connected first, then connect the 12 V battery.
 
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rush6410

Member
Sep 26, 2016
647
655
Montgomery TX
I had a Battery Management System failure that caused the 12V battery to drain with no warning with similar faults as yours. The system is responsible for monitoring and charging the 12V battery from the main battery. My X was towed to SC and took a week to fix. They swapped out the BMS and cabling harnesses. I didn't want to concern you. But, probably an infrequent possible failure. I haven't seen in the forums that anyone else has had the same issue as mine.
 
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Waverider

Member
Oct 17, 2011
116
91
Same issue here. 11month old MX died without warning twice in 3 days. Seems to randomly reboot itself and come back to life. I left mine at work last night after trying to jumpstart it, just saw the notification on my phone that it came back to life at 3am. Gonna drive it home today and park it in my driveway for mobile service appointment on the 8th. Never buying a Tesla again.
 

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