Will the Model 3 be the first Tesla to use a 48 volt system?

[J1mbo]

The specific systems that have been mentioned in the documents I have seen, and reread just now, are:
1. Steering;
2. Driver assistance systems (the reference discussed "decision management" (the term included database processing, analytics, external image processing and decisioning and decision presentment) both the actuators and controls for steering, navigation, braking, speed control plus "sensors" (they listed six types (including radar and Lidar so not all apply to Tesla);
3. active suspension;
4. air conditioning and ventilation (this excluded compressor but mentioned seat heating and cooling);
5. vehicle displays;
6. vehicle controls (this referred to windows, doors, seats, sunroofs and other actuator initiated physical movements);
7. Audio and other entertainment systems.

These systems are all running when the contactors are closed, i.e. the are powered by the main battery (or from the wall charger when plugged in).

Tesla have a 400V battery, so the most efficient thing they could do is run everything off of that with no conversion. However, filling the car with 400V systems might be a little dangerous, so sticking with the industry-standard 12V and concentrating on improving the efficiency of the DC/DC convertor seems to be the sensible route.

FWIW, moving to 48V is complete overkill for systems that need to run off the 12V battery:

a) Keyless entry system
b) Centre console (charge timing, remote access, monitoring)
c) Alarm system
d) Opening and closing the main battery contactors
e) Opening the charge port

The center console is the power hog, so fixing that issue would add much more life to the 12V battery. I read a recent comment that the Model X vampire draw is now down to something like 2W, which is an incredible improvement. Would hope that whatever they did for MX was implemented in the MS refresh as well.

Anyway, M3 is going to be a cheap car. Sticking with commodity 12V items keeps it cheap. Moving to 48V systems will not.

 

[JeffK]

I can think of a whopping zero reasons why they should switch at this point.

 

[Falkirk]

Just saw this from the 3rd quarter investment update (Events & Presentations | Tesla Motors)

"We are now testing vehicle systems such as chassis, the high voltage drive system, and low voltage subsystems such as vehicle controllers, HVAC, infotainment and lighting"

Whatever they chose it's nice to hear they are on top of it already!

 

[ORB]

It's my understanding that the current Tesla A/C compressor runs on the high voltage, so that reference to the Model 3 HVAC being a "low voltage subsystem" would be a change. That would draw quite a bit a current at 12V.

 

[Saghost]

It's my understanding that the current Tesla A/C compressor runs on the high voltage, so that reference to the Model 3 HVAC being a "low voltage subsystem" would be a change. That would draw quite a bit a current at 12V.

Both the compressor and cabin heat are high voltage systems, but the rest of the HVAC is 12V. I don't think there's any real possibility Tesla will do that differently for the 3.