If 12 volt battery dies what does one do?

[jcanoe]

Hello so I had this weird thing happen. On Friday June 2, 2023 I went out to the garage as I needed to run an errand. My MYP was dead no power, I opened the door and couldn’t even close it. The charging cable would not release, drunk or trunk would not open. I did put in a mobile request service and stated that I believe it’s 12 volt. My car is a 2020 MYP with 14k miles.

I never received any warning that the 12 volt system was low. Friday Night it’s like the app connected again I was able to close the door and now it’s telling me the 12 volt needs to be serviced soon and I have an update, whereas for the entire day the car would do nothing.

Has anyone else experienced this? Thank God the car was in my garage at home.

I thought I was supposed to get the warning before the battery went out?

Any information regarding this is welcomed.

You should open a service request in the Tesla app right away. Provide a description in the service request ticket that you received the message that the 12V battery needs to be changed soon.

If you have another vehicle then it is probably best to leave the Tesla Model Y at home. You can keep the low voltage system powered on if you enable Sentry mode at home (usually it is recommended to have Sentry mode set to be off at the home location but in this case Sentry mode will enable your Model Y to continue to function even with the failing 12V battery.) This may enable you to continue to drive the Tesla Model Y if needed until the 12V battery has been replaced, unless the 12V totally dies or develops a shorted cell.

If the Tesla Model Y is parked at home in your garage then it would be best to release the front hood so you can open the hood in the event the 12V battery totally stops working. Leave the Tesla Model Y unlocked. You may want to leave the window of driver's door down so you can reach inside and open the door using the emergency release lever in the event the Tesla Model goes completely dead as happened before.

The Tesla Model Y Owner's Manual has information on how to activate the front hood release in the event that the 12V battery fails (you would need to apply power from a small 12V jump starter pack to a pair of leads that are behind the cover plate in the front bumper where the tow eye attaches to the Tesla Model Y for towing onto a flat bed.) A 9V battery or a 123A battery can also be used to activate the hood release. You would need the 12V jump starter pack to power up the Tesla Model Y if it does not power on due to the 12V battery having failed.

Replacing the 12V battery (if needed) is a warranty repair under the Tesla 4 year / 50,000 mile Tesla vehicle warranty. You may see an estimated cost of ~$165, plus tax show up in your Tesla app messages. Once Tesla determines that this is a warranty repair you account won't be charged.

 

[stopcrazypp]

Hello so I had this weird thing happen. On Friday June 2, 2023 I went out to the garage as I needed to run an errand. My MYP was dead no power, I opened the door and couldn’t even close it. The charging cable would not release, drunk or trunk would not open. I did put in a mobile request service and stated that I believe it’s 12 volt. My car is a 2020 MYP with 14k miles.

I never received any warning that the 12 volt system was low. Friday Night it’s like the app connected again I was able to close the door and now it’s telling me the 12 volt needs to be serviced soon and I have an update, whereas for the entire day the car would do nothing.

Has anyone else experienced this? Thank God the car was in my garage at home.

I thought I was supposed to get the warning before the battery went out?

Any information regarding this is welcomed.

It's mentioned up thread, no warning system is perfect. Lead acid batteries can fail in a way where it is fine one day and the next day it is dead. In ICE cars a heavy load is put on the battery each time (using the starter) so you can get some early signs as the battery gets weaker (it will struggle to start the car), although even in this case many people still don't know until their battery is dead (which is why there are so many mobile battery change services and jumper cables are a thing). With Tesla the loads are might more gradual so there isn't something that necessarily will show the signs, so Tesla added an algorithm to detect it.

Others and up thread you can find plenty of tips. Once you get the warning, the car should keep itself awake so as to no longer rely on your 12V battery. This will give you time to get it replaced. This however will cause more vampire drain on your main HV battery, so you may need to top it off more often. If you want to be extra safe, you can use the tips by others (like enabling Sentry Mode, keeping frunk open so you can jump the car, leaving driver's side window down so you can get into car with manual release, etc).

 

[RoDaddy]

You should open a service request in the Tesla app right away. Provide a description in the service request ticket that you received the message that the 12V battery needs to be changed soon.

If you have another vehicle then it is probably best to leave the Tesla Model Y at home. You can keep the low voltage system powered on if you enable Sentry mode at home (usually it is recommended to have Sentry mode set to be off at the home location but in this case Sentry mode will enable your Model Y to continue to function even with the failing 12V battery.) This may enable you to continue to drive the Tesla Model Y if needed until the 12V battery has been replaced, unless the 12V totally dies or develops a shorted cell.

If the Tesla Model Y is parked at home in your garage then it would be best to release the front hood so you can open the hood in the event the 12V battery totally stops working. Leave the Tesla Model Y unlocked. You may want to leave the window of driver's door down so you can reach inside and open the door using the emergency release lever in the event the Tesla Model goes completely dead as happened before.

The Tesla Model Y Owner's Manual has information on how to activate the front hood release in the event that the 12V battery fails (you would need to apply power from a small 12V jump starter pack to a pair of leads that are behind the cover plate in the front bumper where the tow eye attaches to the Tesla Model Y for towing onto a flat bed.) A 9V battery or a 123A battery can also be used to activate the hood release. You would need the 12V jump starter pack to power up the Tesla Model Y if it does not power on due to the 12V battery having failed.

Replacing the 12V battery (if needed) is a warranty repair under the Tesla 4 year / 50,000 mile Tesla vehicle warranty. You may see an estimated cost of ~$165, plus tax show up in your Tesla app messages. Once Tesla determines that this is a warranty repair you account won't be charged.

Thank You so Much for the tips!!

 

[RoDaddy]

It's mentioned up thread, no warning system is perfect. Lead acid batteries can fail in a way where it is fine one day and the next day it is dead. In ICE cars a heavy load is put on the battery each time (using the starter) so you can get some early signs as the battery gets weaker (it will struggle to start the car), although even in this case many people still don't know until their battery is dead (which is why there are so many mobile battery change services and jumper cables are a thing). With Tesla the loads are might more gradual so there isn't something that necessarily will show the signs, so Tesla added an algorithm to detect it.

Others and up thread you can find plenty of tips. Once you get the warning, the car should keep itself awake so as to no longer rely on your 12V battery. This will give you time to get it replaced. This however will cause more vampire drain on your main HV battery, so you may need to top it off more often. If you want to be extra safe, you can use the tips by others (like enabling Sentry Mode, keeping frunk open so you can jump the car, leaving driver's side window down so you can get into car with manual release, etc).

Thank You!

 

[e645824]

Here is a cross post to the thread for how to open the frunk with a small battery when the 12V lead-acid battery dies:

https://teslamotorsclub.com/tmc/threads/12v-battery-failure-unable-to-access-frunk.241339/page-2​

The thread also contains a lively discussion of alkaline or lithium.

Post #23 and #26 has my photos and shows my four CR123 lithium batteries (about 13 volts) and how my little battery box tucks into the tow-hook compartment. I highly recommend using lithium instead of alkaline.

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021