JeffK
Well-Known Member
Pre-refresh is in the glove box.
You might be thinking of Model X
or the 2015 dual motor (also pre-refresh)
They are all available here: First Responders | Tesla
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You might be thinking of Model X
or the 2015 dual motor (also pre-refresh)
They are all available here: First Responders | Tesla
JeffK
Well-Known Member
I wish they'd stop doing that. Both my EV Fords had lead batteries and both had to be replaced in less than 3 years.
I'm on my 4th 12v battery in as many years in my Model S (and that's pretty common). I hope they make them more reliable for the 3. (But just to be clear, the car warned that the 12v battery needed to be replaced long before it became a problem.)
Zaphod
Galaxy President (former)
Thanks. I guess I was partially right.Pre-refresh is in the glove box.
You might be thinking of Model X
or the 2015 dual motor (also pre-refresh)
They are all available here: First Responders | Tesla
I thought the refresh S and X where the same.
israndy
Supercharger Hunter
What happens when the 12v battery dies? Could I just remove it from the circuit when I am not driving?
-Randy
JeffK
Well-Known Member
The door locks etc are controlled by the 12V battery. Not sure why you'd want the hassle of disconnecting it for no apparent reason.
The high voltage battery charges the 12V with a DC-DC converter and the 12 volt battery supplies power to the high voltage contactors, allowing high voltage current to flow out of the high voltage battery.
israndy
Supercharger Hunter
Just trying to not replace the battery every year. All my current cars have 7+ year old batteries that are working fine
-Randy
-Randy
Thomas Edison
Active Member
Forgive me if this has been mentioned, but why does it matter how bad the 12v battery really is? (For the point of getting in and "starting" the car). As long as the dc/dc inverter is working you should have 12v power. It will be constantly recharging the bad 12v system. So the draw (power door locks) would still get 12v from the source, which really is the high voltage battery. Basically the 12v battery would be acting like a large parasitic drain. Your high voltage battery would drain faster but you would still have power.
The 12 volt battery is needed for the car to function. The computers are powered off the 12 volt battery.
The main battery is only connected to the rest of the electrical system by a contactor using the 12v battery. Without the 12v battery the main battery won't be electrically connected to the rest of the car and can't charge the 12v battery. Chicken and egg. This is for safety.
Thomas Edison
Active Member
As you described it, wouldn't the main battery keep supplying charge amperage to the 12v keeping the system alive. Wouldn't the thing I mentioned still apply? Clearly I'm still missing something.
When you turn off the car it disconnects the main battery. The 12v battery quickly dies and the contactors won't reconnect.
Thomas Edison
Active Member
Ah, that's the part I missed.
Thanks.
So if I wanted to have a plug in cooler on a road trip I would have to keep the car on for it to keep running. Because the battery wound die from the drain.
insaneoctane
Well-Known Member
Pardon my Tesla ignorance, but does the vehicle "charge" the 12V battery? If so, what is the culprit of requiring frequent replacements?
Not normally. When the computer detects that the 12v is running low it reconnects the main battery to charge it and then disconnects it again when done (Teslas can make all sorts of strange sounds when just sitting there like the clicking of the connectors). But if your battery is really bad (at which point you will have had a warning on your dash for weeks to replace the 12v battery) then it it won't be able to reconnect the main battery and the car is dead.
voip-ninja
Give me some sugar baby
It's a traditional lead/acid 12V car battery. It does not get recharged.
Various systems in the car need the legacy 12V battery to function, you can do a search but I believe that early Model S had a notorious problem of dead or early replacement of 12V batteries being needed.
I'm sure there were reasons found but the most likely explanation for this kind of thing is constant parasitic drain on the 12V battery from the vehicle systems.
Traditional car batteries in traditional cars get recharged. That is what the alternator is for.
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