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12V Battery

shokunin

P85 & M3
Feb 28, 2012
1,199
630
Irvine, CA
Yes, the main pack charges it when needed. It does not matter if you're plugged in and charging, the Model S will charge the 12v traction battery automatically using the pack for power.
 

SteveS0353

Member
Aug 23, 2014
365
54
San Diego, CA
Does the Tesla have a 12V battery?
How is it charged?
When you are charging the car at home does it charge the 12V also??

Thank you!

Henry.

Yes, the Model S has a 12V battery. There is no direct connection from the shore power (charge port) to the 12V battery. It's charged from the high voltage LiIon drive battery from time to time. This is the power architecture of the Model S...

Charge Port -> On-board charger -> High voltage LiIon drive battery -> DC-DC converter -> 12V battery.

The 12V battery provides power to the on-board electronics (3G/LTE, WiFi, Keyfob Radios, CPUs, ...) when the main pack contactors are open. This is known generally as "vampire load" and there are numerous threads on TMC about that. The 12V battery provides the power to close those contactors when the car turns on or when the 12V needs to be recharged. This power architecture is part of the safety features. If the car is ever in a crash, first responders can simply sever the 12V loop in the frunk to force the contactors open and thus isolate the high voltage inside the main drive battery, to eliminate the wiring in the car from being energized with potential dangerous high voltage.
 

Henryv

Member
Aug 19, 2015
48
0
Bury, Lancashire, UK
Yes, the Model S has a 12V battery. There is no direct connection from the shore power (charge port) to the 12V battery. It's charged from the high voltage LiIon drive battery from time to time. This is the power architecture of the Model S...

Charge Port -> On-board charger -> High voltage LiIon drive battery -> DC-DC converter -> 12V battery.

The 12V battery provides power to the on-board electronics (3G/LTE, WiFi, Keyfob Radios, CPUs, ...) when the main pack contactors are open. This is known generally as "vampire load" and there are numerous threads on TMC about that. The 12V battery provides the power to close those contactors when the car turns on or when the 12V needs to be recharged. This power architecture is part of the safety features. If the car is ever in a crash, first responders can simply sever the 12V loop in the frunk to force the contactors open and thus isolate the high voltage inside the main drive battery, to eliminate the wiring in the car from being energized with potential dangerous high voltage.


Thank you Steve!!

Most obliged.


Henry.

- - - Updated - - -

Yes, the Model S has a 12V battery. There is no direct connection from the shore power (charge port) to the 12V battery. It's charged from the high voltage LiIon drive battery from time to time. This is the power architecture of the Model S...

Charge Port -> On-board charger -> High voltage LiIon drive battery -> DC-DC converter -> 12V battery.

The 12V battery provides power to the on-board electronics (3G/LTE, WiFi, Keyfob Radios, CPUs, ...) when the main pack contactors are open. This is known generally as "vampire load" and there are numerous threads on TMC about that. The 12V battery provides the power to close those contactors when the car turns on or when the 12V needs to be recharged. This power architecture is part of the safety features. If the car is ever in a crash, first responders can simply sever the 12V loop in the frunk to force the contactors open and thus isolate the high voltage inside the main drive battery, to eliminate the wiring in the car from being energized with potential dangerous high voltage.


Thank you Steve!!

Most obliged.


Henry.
 

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