Confirmed: Newer production R1 only have a single 12v battery, but...

[UnsungZero_OldTimeAdMan]

I know. ?

I posted this thread to be helpful and share new information. I don’t understand the motivation of randos casting doubt on this. It isn’t my job to convince them. Everyone is welcome to do as they wish with what I shared.

Furthermore reality-and just about everyone else-does not care one iota whether they buy it or not.

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[UnsungZero_OldTimeAdMan]

The irony of the top two threads on the forum being "12V Battery Replacement Bricked My R1T" and "Confirmed: Newer production R1 only have a single battery, but..."

People are going to have to be more careful than ever with these systems, imho. Especially since all the instructions currently assume two 12V batteries.

Waiting to see what happens when someone tries the Ohmmu upgrade and slaps a second 12V battery in there in place of the capacitor. #shrug ??

The running improvements are great, but I wonder how the service/support structure can keep up.

 

[NY_Rob]

This is unlikely to ever happen. The whole reason there is a discrete 12V battery is to isolate/turn-off the high voltage pack when the vehicle is "off" by removing power from the high voltage contactors. The discrete 12V battery allows the high voltage contactors to be closed, re-energizing the system. If you relied only on the high voltage system and a DC-DC converter then all the high voltage wiring would always be energized and would be a potential hazard.

Understood, but no reason to tap the 450V contactors. In the same manner you center tap a transformer coil for lower voltage, you can get whatever DC voltage you need by just tapping several lithium cells in the main pack directly. All the lithium cells run in a 3-4volt range... so tap 5 of them 15-20VDC and run that through a buck converter dropping it down to 14.6VDC.

 

[Zoidz]

I

Understood, but no reason to tap the 450V contactors. In the same manner you center tap a transformer coil for lower voltage, you can get whatever DC voltage you need by just tapping several lithium cells in the main pack directly. All the lithium cells run in a 3-4volt range... so tap 5 of them 15-20VDC and run that through a buck converter dropping it down to 14.6VDC.

This would create unbalanced drain of cells in the pack and reduced life. They would never intentionally want to do this. Cell balancing during charging is a band aid but not a solution.

 

[NY_Rob]

I

This would create unbalanced drain of cells in the pack and reduced life. They would never intentionally want to do this. Cell balancing during charging is a band aid but not a solution.

A decent BMS draining from the main bus just before the 400V contactors could easily keep those 5 cells (of course XX cells in parallel for 14.6V 18AH equivalent) up to pack cell average voltage. Yes, that not an ideal workaround, but something like that could work if they put some engineering effort in to it. We have 7776 cells in the main pack... there's no way to get 14.6 volts DC out of that? I can't accept that.

 

[miasm]

A decent BMS draining from the main bus just before the 400V contactors could easily keep those 5 cells (of course XX cells in parallel for 14.6V 18AH equivalent) up to pack cell average voltage. Yes, that not an ideal workaround, but something like that could work if they put some engineering effort in to it. We have 7776 cells in the main pack... there's no way to get 14.6 volts DC out of that? I can't accept that.

To tap off a subsection of the HV battery means you want the BMS on to balance the main pack, and at that point you’re taking all the phantom drain anyways, so no real reason to do it.

 

[C12farmer]

A decent BMS draining from the main bus just before the 400V contactors could easily keep those 5 cells (of course XX cells in parallel for 14.6V 18AH equivalent) up to pack cell average voltage. Yes, that not an ideal workaround, but something like that could work if they put some engineering effort in to it. We have 7776 cells in the main pack... there's no way to get 14.6 volts DC out of that? I can't accept that.

Engineers who design this stuff for a living are shaking their heads right now.

 

[Zoidz]

A decent BMS draining from the main bus just before the 400V contactors could easily keep those 5 cells (of course XX cells in parallel for 14.6V 18AH equivalent) up to pack cell average voltage. Yes, that not an ideal workaround, but something like that could work if they put some engineering effort in to it. We have 7776 cells in the main pack... there's no way to get 14.6 volts DC out of that? I can't accept that.

I could be wrong, but I don’t think there are any manufaturers doing this sort of thing. I’ll trust that the EV power systems engineers have collectively decided against directly tapping the HV for LV for good reasons.

 

[LL75]

Is there an on screen icon that would indicate that the 12V battery is going bad or need to be replace like the Tesla did? We replaced ours in the model 3 at 2 and a half years mark when the warning sign came on.

 

[LevelHeaded]

I have a R1T, VIN 23xxx, built 04/23. I visually checked the battery configuration this morning and, according to the photos in this thread, I have one 12v battery and the capacitor. I don't have the center console/dash 12V nor the Meridian sound.

Does one need to remove the frunk to make this determination?

 

[CaptRat]

Does one need to remove the frunk to make this determination?

I just pulled the plastic facia panel that covers the area between the windshield and the frunk tub. No need to pull the frunk tub to see that area in question. It is held down with 6(+) plastic clips, so not difficult to remove. Just don't force them on removal.

 

[NY_Rob]

I could be wrong, but I don’t think there are any manufaturers doing this sort of thing. I’ll trust that the EV power systems engineers have collectively decided against directly tapping the HV for LV for good reasons.

We'll see how it's done when Tesla is the first to do it...

 

[NY_Rob]

Engineers who design this stuff for a living are shaking their heads right now.

If they are the same "engineers" who designed the completely asinine dual 12V battery system that no other manufacturer in the world uses (for good reason), has caused tons of issues, bricked many vehicles at Rivian's expense causing Rivian to abandon their wonderful design just a year into production.. then they should be hanging their heads, not shaking them!

 

[Megaman0025]

No I’m referring to it being a thing. I have dual and I have physically verified.

You actually have, in your possession? I dual motor vehicle? Asking because I didn’t know anyone has actually received a delivery yet.

 

[jpmc86]

You actually have, in your possession? I dual motor vehicle? Asking because I didn’t know anyone has actually received a delivery yet.

Dual batteries.

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