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If your 12V battery dies....
- Thread starter insaneoctane
- Start date
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- Tags
- Model 3
You could store it in the frunk, wired up to the frunk opener circuit with an external switch (say, in the wheel well), which could even be keyed if you so desired. I think that hits all your concerns. Key operated. Only works when the 12V is dead. Accessible from outside. A bit of security by obscurity (in addition to the aforementioned).
Thank you kindly.
Uncle Paul
Well-Known Member
No need to overthink this. Tesla has already improved the 12v performance and durability.
It is the same with ICE cars. When the battery dies, everything stops.
It is the same with ICE cars. When the battery dies, everything stops.
voip-ninja
Give me some sugar baby
It does seem like an odd area to zero in on and have heart palpitations over. Perhaps someone who makes frequent cross country journeys outside of cell phone range in the middle of winter might have these concerns, but even then the solution of just keeping a 12V lithium ion emergency jump starter handy during those trips would seem to be enough.
I really don't think I am overthinking this. I am treating the question just like an ICE vehicle.
I currently keep my portable jump starter under the passenger seat. If my car dies, yes, I can't unlock it with the fob. But, I can use the physical key to open the door and I'm back in business. I have access to the charger and can get things going in minutes.
How do I accomplish this with the model 3?
On an ICE vehicle the problem with the battery is more critical, I think. When the battery charge is low it may still be able to power the electronics, but it may not have enough charge left to start the engine. In case of Tesla, all you need from the 12-volt battery is to power the electronics. The motors will be powered from the main battery.
Pkmmte
Le meow
voip-ninja
Give me some sugar baby
If it's really life or death enough that you must get into the car immediately there's always this option;
Define "dead"! That's my point: it's rarely dead completely. On an ICE vehicle, I would define "dead" as "it doesn't have enough charge to start the car", but that remaining charge might be sufficient to power the controls or to open the frunk in case of a Tesla.
In the very unlikely event that the battery is discharged completely without giving you any advance warnings, then you can just call Tesla Roadside Assistance or AAA.
So, help me understand how the 12v battery would suddenly die and leave you stranded. Baring a catastrophic failure (I suppose they do happen), a 12v battery would slowly get weak over time, or you could leave the dome lights on and wear it down. In an ICE, it would eventually not be able to crank the motor over, leaving you stranded. Ok. Been there, done that.
But in an EV, you also have the main high voltage pack, with several orders of magnitude more juice in it than the 12v battery has. Unless it is totally drained too, wouldn't the car sense the 12v battery getting low, and start recharging it from the main pack? We know the Model S/X does this often (sometimes more than daily - refer to the multiple threads about replacing the 12v battery). Yes, you need enough juice to pull in the main contactor, but that's a lot less than what is needed to crank an ICE, and the car should have ample time to sense it getting low and start the charge cycle from the main pack.
So, unless the main pack is also totally drained, or unless one ignores the warning messages about needing to replace a weak 12v battery for months, I don't see how one would get into the situation where they'd be prevented from getting into the car.
What am I missing? It seems like you'd really need to try to get locked out (there are easier ways to do that!), and this whole thing is being blown way out of proportion. Smelling a bit of press hyperbole...
But in an EV, you also have the main high voltage pack, with several orders of magnitude more juice in it than the 12v battery has. Unless it is totally drained too, wouldn't the car sense the 12v battery getting low, and start recharging it from the main pack? We know the Model S/X does this often (sometimes more than daily - refer to the multiple threads about replacing the 12v battery). Yes, you need enough juice to pull in the main contactor, but that's a lot less than what is needed to crank an ICE, and the car should have ample time to sense it getting low and start the charge cycle from the main pack.
So, unless the main pack is also totally drained, or unless one ignores the warning messages about needing to replace a weak 12v battery for months, I don't see how one would get into the situation where they'd be prevented from getting into the car.
What am I missing? It seems like you'd really need to try to get locked out (there are easier ways to do that!), and this whole thing is being blown way out of proportion. Smelling a bit of press hyperbole...
stopcrazypp
Well-Known Member
Yeah, I don't see it likely that the 12V battery would just die completely (such that door locks don't work). I've had it in my ICE car where it can't crank the motor (forgot to turn off lights), but never to the point that it can't even power the door locks. Plus, as you point out, the HV pack in this case will recharge the battery as it gets low.
However, in my ICE car, when I park for a long time, I disconnect the 12V battery. This is probably not viable anymore in the 3.
I do wonder how much power is needed to pop the frunk. Maybe those tiny 12V batteries for remotes is enough to pop the frunk. Otherwise I would have to carry a lithium ion jump starter every time.
Well I guess we would need to hear from current MS MX owners who have had to replace their 12v batteries to help folks understand how it can happen. It does happen. I can't tell you how often. I guess my point was less about how often or even why, as much as where the hell do I put my portable charger /starter (which I already own) and is about half the size of a ream of paper in my M3 so that I can get to it when I need it....
Xiao ma ge
Member
You could store it in the frunk, wired up to the frunk opener circuit with an external switch (say, in the wheel well), which could even be keyed if you so desired. I think that hits all your concerns. Key operated. Only works when the 12V is dead. Accessible from outside. A bit of security by obscurity (in addition to the aforementioned).
Thank you kindly.
You could store it in the frunk, wired up to the frunk opener circuit with an external switch (say, in the wheel well), which could even be keyed if you so desired. I think that hits all your concerns. Key operated. Only works when the 12V is dead. Accessible from outside. A bit of security by obscurity (in addition to the aforementioned).
Thank you kindly.
Brass Guy
Active Member
Model S and X most often issue a warning that the 12V battery is not performing as it should, and that you should contact Tesla soon. There have been many Model S that the 12V battery gave this message with well under a year of service. My original one lasted nearly 4 years.
Tesla does not consider this an immediate issue. After this message, you have at least a few weeks before the battery is too weak to bring up the systems.
What can also happen is the DC-DC converter that powers the 12V systems fails. The 12V systems drain the 12V battery and the car shuts down (usually after issuing increasingly alarming messages). In this case, you'd be in the car with your battery booster; but you'd have to power the 12V system completely off that booster which might not get you too far before it too was drained.
Arriving at your parked car with a dead 12V battery is quite unlikely. In this case, yes you'd probably have to wait for assistance. Unless you want to modify your brand new car as per @Topher's suggestion. I wouldn't, it's less likely than a flat tire.
Tesla does not consider this an immediate issue. After this message, you have at least a few weeks before the battery is too weak to bring up the systems.
What can also happen is the DC-DC converter that powers the 12V systems fails. The 12V systems drain the 12V battery and the car shuts down (usually after issuing increasingly alarming messages). In this case, you'd be in the car with your battery booster; but you'd have to power the 12V system completely off that booster which might not get you too far before it too was drained.
Arriving at your parked car with a dead 12V battery is quite unlikely. In this case, yes you'd probably have to wait for assistance. Unless you want to modify your brand new car as per @Topher's suggestion. I wouldn't, it's less likely than a flat tire.
stopcrazypp
Well-Known Member
I don't think there has been a case where the 12V just suddenly dies. Rather there are lots of warning messages asking to replace the 12V battery.
