I'm just curious if Tesla will eventually stop replacing 12 volts batteries under warranty with another lead acid battery and instead use them with the Lithium Ion battery that is now standard in their cars. Obviously they are going to use up their stock of lead acid batteries first but it would be nice if I could get a warranty replacement, before my warranty runs out, with the newer battery. And yes, I know my battery has to fail first....fingers crossed.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Will Tesla Stop Using 12 Volt Lead Acid Battery as the Warranty Replacement?
- Thread starter Resist
- Start date
davewill
Active Member
Not likely. The newer cars have a different charging profile for the newer battery and different connectors. Maybe other component differences, too.
Well, other than the connectors, seems just a software update would fix the charging profile. Even the connectors would be easy to change out.
There is zero reason for tesla to upgrade an existing car like this. You cant even pay tesla to upgrade it currently from a lead acid to the new 12v battery, even if you wanted to, so there is little chance of this ever happening for existing cars that dont already have that battery.
BigNick
Infamous Fat Sweaty Guy
I would say it's a "hard" no - the new battery and MCU appear to be a package unit (from the cars I have seen and/or seen the screenshots of "Additional Information".)
Intel-based MCU cars have the conventional 12V and Ryzen-based MCU cars have the 15V Li-Ion battery. If there are exceptions to this rule, I haven't seen any.
Intel-based MCU cars have the conventional 12V and Ryzen-based MCU cars have the 15V Li-Ion battery. If there are exceptions to this rule, I haven't seen any.
AlanSubie4Life
Efficiency Obsessed Member
Why are you so worried about this battery?
It should not be a big deal to recover if you take some basic steps to have backup (ability to detach negative terminal, emergency jumper battery, & 12V hidden behind tow hook cover). Haven’t tried it though!
Also it often (not always) fails gracefully.
And replacements are cheap. Initially I worried about it on road trips but it seems you can just disconnect the 12V and then you *might* be fine. YMMV.
I do wish that someone with one of the new batteries would measure the vampire drain with the new setup and using the known battery parameters (capacity, discharge curve, etc.) determine average sleep power.
Last edited:
Isn't it obvious? Tesla has had known issues with this battery. I don't want to be stranded someplace without cell coverage in the middle of the night. Or end up missing an appointment because the 12volt battery died and I never got a warning that it was going bad. Worse yet, packed up and ready to go on a trip and it dies, then being told by Tesla that they are out of 12volt batteries and it could be a couple weeks or they have them but they can't get someone to me for a few weeks either.
AlanSubie4Life
Efficiency Obsessed Member
Right, I was worried about this too, but then I realized that apparently you don’t need the 12V battery (though then I would have to worry about the obligatory massive phantom drain which could be a concern - but in that case in remote areas I would just disable the car completely (force open the contactors with the disconnect)), and then come back and resuscitate the car with the jumper on my return several days later).
A bit stressful but all completely workable. I think the only issue could be a 12V issue detected while I am away from the car for multiple days, which could lead to excess phantom drain and leave me stuck (if too far from electricity) because I would not have an opportunity to disable the car before leaving it.
Also: Arguably it is easier to get a spare 12V in a pinch, than it is to get a spare Li-ion 15V. I’d still try to not bother to replace it with anything but Tesla OEM (I’m cheap!) and just disconnect it, but just my thoughts.
It does sound like it is relatively straightforward to just connect 12V jumper with the battery removed and re-enable the vehicle. Once the contactors are closed in theory you should be fine (just keep that 12V jumper pack with you and charged up).
Maybe this all fails horribly for some reason but have not heard of a case. When my 12V failed it was a non issue. The car just stopped using it. I did not even have to disconnect it.
If my 12V failed before a trip I would just make sure my backup plan worked, starting from a disabled vehicle (no battery, contactors open). Then I’d go on the trip and get a spare battery from Tesla at the most convenient time. I’ve even got an extra 10mm wrench packed in my Lithium ion jumper case, and have rehearsed the contactor disconnect procedure under the rear seat. I’m ready!
Last edited:
Since when isn't the 12volt battery needed and what massive phantom drain is there? You need the 12volt battery to unlock doors and have lights and display power.
If you are saying I could just use a 12volt jumper pack in place of the OEM 12volt battery in an emergency situation, well that's an interesting idea but just another expense and thing I have to keep in my car. And still a pain to have to get out unlock the hood then connect the pack to the battery, which is completely inconvenient in the rain or in a bad part of town late at night. The fact remains that Tesla knows there are 12volt lead acid battery early failure issues and isn't proactive.
My warranty expires December 1st this year, if it doesn't fail before then I will have pay for the replacement battery. Even knowing there are battery issues Tesla won't replace it for me until it actually dies. I can't even call the closest Tesla Service Center because they don't have a direct number to talk to person anymore, so I can't find out if they even have the batteries in stock.
As I type this I'm more curious about your 12volt jumper battery solution. How long would it last? Because it seems like with all the things it has to power in the car, it would drain down rather quickly. So going on a trip with a dead battery and the jumper might not be a good idea.
AlanSubie4Life
Efficiency Obsessed Member
From what I understand, you can just disconnect the 12V (negative terminal) and the car will be fine as long as the contactors are closed at the time. It will just complain about not having a 12V. This is what people here have posted.
And the phantom drain is because the car just stays awake all the time in this case. This also happens if your 12V fails gracefully (happened to me). It’s fine. 20 miles a day or whatever.
The only issue is if the contactors open, you have to find a way to close them again (requires a 12V source). That is where the jumper comes in.
You only connect it briefly. The car draws a couple hundred watts while using the battery, so you’d want to disconnect it after the car closes the contactors and powers on (but at that point it stops using the battery). All with negative terminal disconnected (important because you do not want to attempt to rescue a dead short).
I don’t know how long it would last and I would definitely charge it in the car after using it (and be sure to keep it with me).
I have no idea if this will work, but that is the plan.
Anyway the battery is only $85 but you get what you pay for as they say. Definitely inconvenient but also no big deal. I assume the Li-ion battery is even cheaper (hopefully sub-$50).
I have a 12V battery behind the tow hook cover, and a 12V lithium jumper charged up, with a 10mm wrench as well, in the frunk.
Last edited:
This is the opposite of what I've heard. The car is using the 12V battery to power the doors, the headlights, the display, computers and so on. If it goes dead or you disconnect it, then none of those things work. The main drive battery pack doesn't power any of those things. If I am misinformed then educate me.
And I also have a small battery behind the tow hook door as well.
AlanSubie4Life
Efficiency Obsessed Member
I believe that is incorrect. When the contactors are opened (sleeping), the 12V is used. When the contactors are closed (idle), the main battery is used via the DC-DC.
You can see in fact that the car is charging the battery sometimes when the contactors are closed, putting current into it, so should be a nonissue to remove it. It’s not used as a path to the the main 12V bus - the battery is one of the things attached to that bus (and additionally it has the special ability to close the contactors and some interface with the 12V terminals in the tow hook area, which only work if the 12V has failed).
I do not believe the 12V needs to be there to keep the contactors closed - I think that is “latched” somehow. That would be the key thing to determine but pretty sure it is not required.
You can always experiment yourself. Others here (@rrolsbe I think) have confirmed this. I am certain that I read that if you disconnected it it would just complain about a missing 12V battery (again, crucially, the car must be awake at the time!).
Additionally as I said my car basically told me this - it said standby power would be high, electrical system unable to support all features, and software updates would not occur, with a rapidly rotating message. It had bypassed the battery by ensuring the car would not sleep.
It would be a very bad design if the car doors and everything else failed if the 12V battery failed. This does happen, but not immediately (when driving). I think it happens only with certain 12V failure modes that cause the car to not realize that it cannot open the contactors and go to sleep.
Another thing to do if you suspect you have a bad battery (or you have recovered it) is just turn on Sentry Mode everywhere to ensure the car does not sleep (assuming you have plenty of margin to 20%!).
Last edited:
Well, I still don't think that is correct. The main drive battery does not power any 12 volt system, except for topping off the 12 volt battery. In fact, when my car only a few months old it wouldn't power on. Tesla sent someone over with a 12 volt power jumper, unfortunately that didn't fix the issue because it was something greater. But Tesla and the service buy both said if the 12 volt battery is dead those systems don't work.
AlanSubie4Life
Efficiency Obsessed Member
Only one way to find out. Maybe I’ll try it and let you know (I really should anyway!). Or perhaps @rrolsbe can confirm.
A lot of people try the 12V jumper with the offending battery in place. This may fail since it may be a dead short.
How do you know the car’s DC-DC powers only the 12V battery, and then that is daisy-chained to everything else? (I am pretty sure this is false; it would make charging the 12V battery properly very difficult because you would have to know what the power draw is of everything downstream of the 12V and subtract that current from what you are supplying to the 12V, to get exactly the right charging profile - it makes no sense.)
It’s true that if the 12V is dead and the contactors are open, nothing will work.
I've found several articles where if the 12V battery was dead, then the drive battery pack couldn't be charged. This tells me that the 12V battery has to have continuous power, so I don't think jumping it without it being charged up, works. But yeah, I'm curious if it works for you. Keep me posted.
This is what happens if you take your 12v out. It just lets you know it's disconnected. Else you wouldn't be able to see the warning on screen ; )
I think it shuts down eventually next time the car sleeps or is parked for a while maybe.
Personally I've had no problems with the 12v and I am going on year 4.
Last edited:
AlanSubie4Life
Efficiency Obsessed Member
Thanks.
Great, looks like I am likely good to go. I think the key here is probably to disconnect the main 12V if for some reason you need to “jump” the car.
That’s phase two of the inquiry. Maybe someone has actually done this, for science (wake the car from a dead state with the 12V jump and no 12V). Obviously screwing around with my own car, if it is not a necessity, is not the most appealing.
There’s also the slight nagging worry about driving around with that warning…but you could reconnect your broken 12V and try to keep the car awake.
ucmndd
Well-Known Member
Your single-minded quest to make a problem where there isn’t one has polluted your brain with a bunch of patently false information.
The 12v system is - without a doubt - powered from the HV battery through the DC-DC converter when the contactors are closed (aka any time the car is awake).
If your battery fails before 4 years, Tesla will happily replace it for you with another $80 lead acid battery. Asking multiple times if they’re going to retrofit a completely different system for you out of the goodness of their hearts to address an issue that you’ve mostly manufactured isn’t going to change the obvious answer (“no, they’re not”).
If you’re this paranoid and worried you’re going to get stuck in a “bad part of town” without warning then you should spend the hundred bucks to replace the battery proactively. Hell, start a gofundme or something.
Tesla will not solve this for you.
AlanSubie4Life
Efficiency Obsessed Member
Yes, the only possible concern here is how to un***k yourself if you do have an unexpected failure. That’s a valid concern.
Hopefully the method outlined above provides correct information on how to recover a dead vehicle that only has a 12V failure and no other issues. The only thing not covered here is the trivial disconnect procedure of the HV battery, done by pulling the interlock loop connector under the right rear passenger seat.
This should be done before you touch the 12V battery, and redone after the battery is replaced. There’s a specific sequence to follow (documented online). You can follow that sequence to the letter and everything should be safe. While this is for an Ohmmu battery, I am not recommending (or not recommending) that product. It was just convenient and provided all the details.
My 31Wh jump battery hopefully can provide 300W to the vehicle for ~6 minutes (surge power should not be an issue). So it is important to work fast to get the contactors closed once the 12V system starts up (I would count on no more than two minutes).
Last edited:
I think the ohmu instructions are that way because I think they want the inverter off when you remove the battery. Otherwise that 12v line is hot and anything it touches is ground. The whole area is metal. Also you want the car to do a reset anyway with a battery replacement.
The procedure for jump starting the car is the same as a normal car if you have the lead acid. It's in the Tesla manual. Look under instructions for transporters or just search jump starting. It says to just connect it to the battery terminals and follow the instructions on your jump starter.
Similar threads
