Good call. I was going to shut off sentry thinking it might have some drain on the 12v even though sentry is powered by the main battery.
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If 12 volt battery dies what does one do?
- Thread starter RidgeRunner
- Start date
Good call. I was going to shut off sentry thinking it might have some drain on the 12v even though sentry is powered by the main battery.
ATPMSD
Active Member
This is the right answer! Here’s a tip, never turn Sentry off unless you are prepared to deal with a dead battery. I keep a jumper in my Frunk and know how to open it. But there are many times I don’t want to run the risk, such as when out to dinner, so Sentry is left on. You should probably never have it off if your wife is using the car.
As a rule I always have sentry on, except when at home and in the garage. I used to leave it on in the garage as well but I would get anywhere from 20-100 incidents each night due to headlights coming through the garage door windows or side window from neighbors turning in and off their lights at night. Only other exception is if battery it too low and car shuts it off by default.
EVer Hopeful
Active Member
That was an amusing statement, at least to people like me who are (i) From England and (ii) still very juvenile
Urban Dictionary: have it off
Maybe a silly concern, but does anyone using the "A23-battery-in-tow-hook-compartment" method have experience leaving it in there throughout the warmer months? I imagine it gets pretty hot in there when it's 90-100F outside. My understanding (which could be totally wrong) is that alkaline batteries need to get pretty hot (150F+) before they're at risk of bubbling, blowing up, etc. and of course will experience lifespan degradation in extreme temperatures.
I know we're already talking about a rare scenario where the battery is dead and you don't have your key card (would this even work if 12V is dead?), but maybe the prudent decision is to replace the A23 every 6-12 months despite Duracell's shelf life recommendations or at least pop open the cover maybe once a season to check that it's still cozy and in one piece in there? Last resort is to call roadside assistance, so not a big deal either way - just thinking out loud.
I know we're already talking about a rare scenario where the battery is dead and you don't have your key card (would this even work if 12V is dead?), but maybe the prudent decision is to replace the A23 every 6-12 months despite Duracell's shelf life recommendations or at least pop open the cover maybe once a season to check that it's still cozy and in one piece in there? Last resort is to call roadside assistance, so not a big deal either way - just thinking out loud.
Consider bringing a 12V jump starter with you on trips and take the jump starter out of the Tesla Model Y when you arrive at your destination. (You can also keep the jump starter in the frunk so you can readily access the jump starter if needed by opening the frunk using a 9V battery or A23 battery. (The A23 battery is not going to be able to boot up the computer, you would need a jump starter to boot up the Tesla Model Y if the low voltage battery fails.
The low voltage (15.5V) lithium battery is designed to last the life of the Tesla Model Y. The older 12V lead-acid battery can last up to 4 years.
When the Tesla Model Y is parked with Sentry mode active the Tesla Model Y remains in Standby mode where all of the low voltage systems are powered by the Power Conversion System (PCS.) The low voltage battery only powers the Tesla Model Y when the Model Y enters sleep mode; only powers the LTE and BT modems, door locks and vehicle alarm (not Sentry mode.)
stopcrazypp
Well-Known Member
Pop open the cover occasionally and check the voltage of the A23 with a multimeter. If the battery is leaking, the voltage will start to drop (you can keep a log of the voltage to see how it degrades with time). I had leaky AA Duracells, and while they still worked, voltage has dropped from 1.5V (from ok ones in same batch) to 1.2-1.3V. If you keep it in a clean ziplock bag, any leaks should also be fairly obvious.
I'm not sure what the key card has to do with it. The A23 only is there to allow you to pop the frunk when your battery is dead. You would still need a jump starter to start the car and a working key to unlock it. If the 12V is not dead, the car needs to be unlocked for the tow hook line to be able to pop the frunk (this feature was added in an update a long time ago, given people had concerns about security).
12V working - applying ~9V to ~12V power to the leads behind the tow hook cover will not unlatch the hood. (This enhancement was made so that some random person cannot apply power to leads and open, access the front trunk.)
12V dead - applying power to the leads behind the tow hook cover will release the hood. (This is so you can access the 12V battery and use a jump starter to boot up the Tesla Model Y computers.) *
12V weak - applying power to the leads may not release the hood (This remains a problem.)
* Once the Tesla Model Y computer has been booted you can use either the phone key or the key card to unlock and drive the Tesla Model Y.
stopcrazypp
Well-Known Member
Actually it does if the car is unlocked, as demonstrated here starting at around 5 minutes in:
One strategy that worked for me on a road trip: I received a low 12 volt battery message several hundred miles from home. We decided to keep on our pathway for home and just try to prevent the car from going to sleep by leaving the climate control on all the time when we left the car to eat, sleep, etc. It cost us a few miles of range, but the car stayed awake and was fine. We couldn't charge cell phones as the car turned off the USB power when the error message came in, but we made it home fine after a couple of days and I purchased a new battery from the local Tesla service center and swapped it out.
Sadly in my case I only got 2.5 years and 10K miles out of mine. The car being in a cool garage year round and driven more at night. Also usually parked in a structure and less a lot during the day.
Guess it was a dead as it didn’t see much in the way it harsh conditions.
ATPMSD
Active Member
Energizer batteries are guaranteed not to leak.
Energizer® No Leak Guarantee - Energizer
Energizer® No Leak Guarantee About Batteries How Batteries Work What is Inside a Battery Battery Chemistry Battery Leakage Battery History Battery Care No Leak Guarantee Battery FAQ PROTECTS YOUR DEVICES FROM DAMAGING LEAKS.* Even as battery technology has evolved, battery leaks are still a...
www.energizer.com
stopcrazypp
Well-Known Member
That's just a warranty policy, duracell has the same thing:Energizer batteries are guaranteed not to leak.
Energizer® No Leak Guarantee - Energizer
Energizer® No Leak Guarantee About Batteries How Batteries Work What is Inside a Battery Battery Chemistry Battery Leakage Battery History Battery Care No Leak Guarantee Battery FAQ PROTECTS YOUR DEVICES FROM DAMAGING LEAKS.* Even as battery technology has evolved, battery leaks are still a...
I see no indication the batteries themselves are designed any different to prevent leaking. Fairly trivial to find examples of Energizers leaking (even ones with later expiration than mine, which were 2025):
EEVblog #1349 - Energizer Battery Leakage - MADE IN USA - Page 1
EEVblog #1349 - Energizer Battery Leakage - MADE IN USA - Page 1
www.eevblog.com
It's much cheaper to offer such a warranty (which few will take up on) than to design it to actually never leak.
ATPMSD
Active Member
FWIW I use them in expensive dive gear electronics and the manufactures warn against using Duracell batteries. I have personally seen many Duracell batteries leak and I never seen an Energizer leak.
Each to their own.
Each to their own.
stopcrazypp
Well-Known Member
I'm not denying perhaps Energizer alkalines are less likely to leak than Duracell (especially given duracell have been through acquisitions so they likely have cheaped out to cost cut), but just saying they still leak. There are other chemistries like lithium that really would practically never leak, but A23s tend to be alkalines.
ATPMSD
Active Member
To be fair, I should note that I only use Energizer Ultimate Lithium. They do cost more but boy do they last!
stopcrazypp
Well-Known Member
Ok, that explains it. Yes lithium would almost never leak because they are much dryer and they don't swell up like alkaline do when they start to expire.
Call Tesla Service, there is a small wired contact behind the bumper "plug" on the drivers side. The Tesla Technician will wave his magic want over this contact to allow you to open the doors and frunk where the 12v battery is located in order to change it out. This happened to us after we returned from a 2 week trip to New Zealand. It was actually our fault and how we managed to drain the 12v battery has been addressed and corrected by Tesla. I DO WISH our Tesla would provide some sore of warning when the battery level is low enough to be a concern and need replacement
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