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If 12 volt battery dies what does one do?
- Thread starter RidgeRunner
- Start date
Is it not possible to wire up two (smaller?) batteries so that if one battery dies the one is still up and running?
Anyway Tesla is easy enough to jump to get into.
When someone totaled one of my older ones I found instruction in 5 min on how to get into the car for the salvage yard.
There are so many Tesla’s out theee I would think most tow truck drivers know how to do it. And AAA will even bring you a new battery and install there in the right circumstances.
Anyway Tesla is easy enough to jump to get into.
When someone totaled one of my older ones I found instruction in 5 min on how to get into the car for the salvage yard.
There are so many Tesla’s out theee I would think most tow truck drivers know how to do it. And AAA will even bring you a new battery and install there in the right circumstances.
stopcrazypp
Well-Known Member
The manual has instructions on how to pop the frunk when the 12V battery is dead:
Model Y Owner's Manual | Tesla
As does the DIY Guides:
Model Y Do It Yourself | Tesla
For most people, it's a simple matter of calling Tesla Roadside or AAA and they can send someone with a jump starter to pop the frunk and jump start the car.
If you want to prepare for a situation with no outside help, you can stash a small 12V A23 battery in a small zip lock bag (to prevent corrosion) behind your tow hook cover. That can be used to pop the frunk in case the 12V dies. You can have instructions in there too if it fits. Then leave your jump starter in your frunk instead of trunk.
I did that about a year ago, and fortunately haven't had to use it yet. Someone saw me stuffing the battery in the tow hook spot, and joked that I now I could "hot wire my frunk". Pretty much, yeah.
stopcrazypp
Well-Known Member
On that subject, A23s have self discharge, Duracell rates their's at 10% per year. So probably makes sense to check voltage or swap new ones in if they have been there for a while to avoid situations of it being out of charge (or perhaps have a few so they can be used in parallel to reduce voltage sag, which might help if they are lower on charge).
https://www.duracell.com/wp-content/uploads/2020/02/MN21_0620192.pdf
I should note there are probably corner cases where the 12V battery in the car is in a middle state: not enough charge to power the car's locks, but enough charge that the frunk can't pop. Just a warning this is a possibility.
CyberGus
Not Just a Member
ha funny
And..... have a little jump starter battery in the frunk. thanks. Now wondering if one gets a warning that it is fixing to die. see that one can measure the voltage at the cigarette lighter and maybe infer that battery is getting weak. I did measure it yesterday to be 14.5 but is this while the battery pack is charging it up? I must determine when is the best time to measure it to know if its weak, anyone know?
I did find the instruction for this procedure after posting the question. and intend to get the 12 volt A123 and will post the instruction on her phone.
And..... have a little jump starter battery in the frunk. thanks. Now wondering if one gets a warning that it is fixing to die. see that one can measure the voltage at the cigarette lighter and maybe infer that battery is getting weak. I did measure it yesterday to be 14.5 but is this while the battery pack is charging it up? I must determine when is the best time to measure it to know if its weak, anyone know?
I remember an old Twitter post where someone asked if the car could advise when it needed to be replaced far in advance. Musk said that would be added. Not sure if it ever was. Given your wife didn’t mention anything I guess it never was. If you felt it necessary I suppose it wouldn’t be too complicated to run a set of wires from the battery into say the glove box or center console with a display for battery info; perhaps even only when a button is pressed to avoid trickle loss. RV’s use these sort of things all day long.
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stopcrazypp
Well-Known Member
With the latest software updates, there is less worry of this as the car checks up on 12V battery health automatically and will keep the car awake if it detects the 12V battery is failing and will give a warning.
This typically is enough to prevent the situation of someone being stranded with a dead 12V battery (as the car remains powered by the HV battery).
Here's an example of how the warning looks:
The cigarette outlet voltage is the voltage from DC-DC converter. To know the 12V battery voltage you need to check the actual 12V battery terminal with the car asleep. However, just knowing the battery voltage doesn't tell you much about its health. An actual test with a load tester with battery disconnected from car is typically how it is officially done. Some people have a wireless battery monitor to check how it is charging/discharging, but I don't think it necessarily will tell you how battery health is doing.
As mentioned however, Tesla automatically checks the health of the 12V battery and typically can give a warning when it is on its last legs. Also generally they last about 3 years, so that is a ball park.
stopcrazypp
Well-Known Member
The detection is not perfect (sometimes batteries can seem fine all the way up until it fails). Some of the older batteries (like from the original 2018 bunch) may have been damaged more before Tesla adjusted the 12V charging/detection mechanisms. The OP didn't mention the battery actually failed yet, I was presuming he was looking to prepare for that occasion.
EVer Hopeful
Active Member
Funny enough I just for the messages. Yes multiple messages. Coincidently, I already had mobile service scheduled for repeater cameras (turn signal flash), rear camera trunk cable harness and a clicking from wheel well when turning hard right.
I have a long trip tonight I hope the battery holds up till tomorrow. Especially since the learn more notes says car MAY power off while driving and / or might not turn on the next time after being turned off.
The on screen message states non essential items will be shut off like radio, nav, HVAC, seat heaters.
I have a long trip tonight I hope the battery holds up till tomorrow. Especially since the learn more notes says car MAY power off while driving and / or might not turn on the next time after being turned off.
The on screen message states non essential items will be shut off like radio, nav, HVAC, seat heaters.
Plug in the Tesla Model Y and leave Sentry Mode on or set Camp mode with HVAC fan only on Low. The Tesla Model Y will remain powered on, not enter sleep mode. In this way the Tesla Model Y's 12V systems are powered by the on-board power conversion system DC-to-DC power inverter, not the 12V battery.
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