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

jboy210

Supporting Member
Supporting Member
Dec 2, 2016
5,688
3,688
Northern California
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.

That sounds like a loose cable or bad connector. When I was a mechanic I fixed several dozen of these. Ford, Chrysler, BMW, and Mercedes has issues with these. Don't ever remember having issues with a Japanese manufactured car.
 

yogi4

Member
Jun 19, 2018
96
46
Austin Tx
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.
Did you try reporting this to Tesla Service Center . They should take care of it and provide you a loaner car .
 
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Waverider

Member
Oct 17, 2011
116
91
Did you try reporting this to Tesla Service Center . They should take care of it and provide you a loaner car .
I’ve got a mobile service appointment for Sept 8. Going to try and get it into my driveway from work and then just leave it there until the service appointment. For my last service they told me they don’t have loaners at Bakersfield. Which was a lie because when I got there a guy was dropping off his loaner.
 

scottf200

Active Member
Feb 3, 2013
4,293
4,251
Chicagoland ModelX S603
I’ve got a mobile service appointment for Sept 8. Going to try and get it into my driveway from work and then just leave it there until the service appointment. For my last service they told me they don’t have loaners at Bakersfield. Which was a lie because when I got there a guy was dropping off his loaner.
"lie" -- seems like an odd judgement as people can bring back loaners in a wide timeframe to pick up their cars SO Tesla may not have a loaner one minute but then one comes in the next minute (which needs to be checked in, then possibly charged, etc).
 

rjdoc74

Member
Feb 27, 2014
928
726
LA, CA
I’ve got a mobile service appointment for Sept 8. Going to try and get it into my driveway from work and then just leave it there until the service appointment. For my last service they told me they don’t have loaners at Bakersfield. Which was a lie because when I got there a guy was dropping off his loaner.

You are absolutely right, I have caught service advisors on lies multiple times including loaner availability. They tell you what serves their purpose at that particular moment without any regard about getting caught on a lie.
 

VikH

Supporting Member
Supporting Member
Nov 23, 2015
1,092
1,042
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.

Got the tester and it looks like my 12V is pretty crappy. However, I don’t want to go through the hassle of trying to get Tesla to replace it if my reading is not correct. I did a quick test and input 40Ah based on the picture of the battery you posted. I then connected the red clamp to the post and the negative to a metal piece of the body. Is that correct? Does the car have to be running to get an accurate test?

A87CA12B-2E76-4140-87CD-066961E1A10A.jpeg
 

scottf200

Active Member
Feb 3, 2013
4,293
4,251
Chicagoland ModelX S603
Got the tester and it looks like my 12V is pretty crappy. However, I don’t want to go through the hassle of trying to get Tesla to replace it if my reading is not correct. I did a quick test and input 40Ah based on the picture of the battery you posted. I then connected the red clamp to the post and the negative to a metal piece of the body. Is that correct? Does the car have to be running to get an accurate test?
Yikes. That doesn't look good.
Test I've seen with it connect to both battery post (not neg to body). Also I'm guessing AGM Flat Plate and 500 CCA as settings (along with 40Ah).
I don't think the car should be ON (that is someone sitting in the drivers seat).
Also did you remove the surface charge and how did you do that? (I'll probably flash the lights a few times from the phone app and/or roll the windows done (ie. drive those motors)).
What is a surface charge on a car battery?
A battery with surface charge has a slightly elevated voltage and gives a false voltage-based SoC reading. ... To normalize the condition, switch on electrical loads to remove about 1 percent of the battery's capacity or allow the battery to rest for a few hours.
Source: Water Loss, Acid Stratification and Surface Charge - Battery University

Ancel BA101 user manual: https://www.obdii365.com/upload/pro/ba101-battery-tester-user-manual.pdf
 

ShawnA

Supporting Member
Supporting Member
Nov 13, 2017
1,005
743
Edwardsburg, MI
Hi @VikH,

The device is measuring resistance...
So, if the place you connected has higher resistance due to
corrosion, paint, or something else it would identify your battery as
a "replace."

Is there any reason you did not connect the negative to the battery?
Perhaps try to attach to the "jumper cables" present on the X to stay
away from the battery...

Shawn
 

VikH

Supporting Member
Supporting Member
Nov 23, 2015
1,092
1,042
Midwest, USA
Yikes. That doesn't look good.
Test I've seen with it connect to both battery post (not neg to body). Also I'm guessing AGM Flat Plate and 500 CCA as settings (along with 40Ah).
I don't think the car should be ON (that is someone sitting in the drivers seat).
Also did you remove the surface charge and how did you do that? (I'll probably flash the lights a few times from the phone app and/or roll the windows done (ie. drive those motors)).


Ancel BA101 user manual: https://www.obdii365.com/upload/pro/ba101-battery-tester-user-manual.pdf

Hi @VikH,

The device is measuring resistance...
So, if the place you connected has higher resistance due to
corrosion, paint, or something else it would identify your battery as
a "replace."

Is there any reason you did not connect the negative to the battery?
Perhaps try to attach to the "jumper cables" present on the X to stay
away from the battery...

Shawn

Didn't want to go through the hassle of removing the frunk tub to get to the battery, but seems like that is what I need to do for an accurate read. I'll post my results when I do this.
 

scottf200

Active Member
Feb 3, 2013
4,293
4,251
Chicagoland ModelX S603
Didn't want to go through the hassle of removing the frunk tub to get to the battery, but seems like that is what I need to do for an accurate read. I'll post my results when I do this.
Video on the process of changing your battery that includes steps to get to it (though it missed disconnecting the first responder look as was pointed out above in the service manual).

Watch at x1.5+ speed tho.
 

scottf200

Active Member
Feb 3, 2013
4,293
4,251
Chicagoland ModelX S603
Didn't want to go through the hassle of removing the frunk tub to get to the battery, but seems like that is what I need to do for an accurate read. I'll post my results when I do this.
I just finish getting access to my 12v battery post and cleaning my filter while I was in there (ie. vacuuming it).
I leaned in and use the menu to manually turn the lights on for several minutes for the surface drain.

* 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.
W5MpKOQ.jpg
 
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