# 12 VOLT Accessory power



## Groveite (Oct 15, 2021)

I replied to a post without checking the date and after the fact saw it was from more than a year ago so am trying to start a fresh thread and hope that no-one is offended by my breach of etiquette. I'm very new to Tesla (Y on order for March/April delivery) and have been wondering about the 12 V sources as well. We use a 12V compressor fridge/freezer frequently (draws 5 amps @ 12V) and I am unsure if the 12V battery will support that use? Is the 12V charged from the 480 pack or only when plugged in? This a steep learning curve for an old guy and I'm reading through the manual and lurking in the forums to help speed the process! Thank you.


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## oshw (May 9, 2018)

The 12V aux plug should be able to support a 12A continuous load.

It runs off of the large high voltage pack DC/DC converter when the car is not sleeping... So as long as the car is awake, any aux loads would be powered from the energy stored in the main battery pack.

Not sure how tolerant the port is of high inrush currents or compressor loads at startup... Those can be much higher than continuous ratings.

Edit: awake also meaning modes like Sentry mode or camping mode... Where the car power consumption is more than ~100W - the large 12V converter (the PCS, power conversion system) would be on running the electronics off of the main pack along with the aux outlet in the center console.


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## Groveite (Oct 15, 2021)

oshw said:


> The 12V aux plug should be able to support a 12A continuous load.
> 
> It runs off of the large high voltage pack DC/DC converter when the car is not sleeping... So as long as the car is awake, any aux loads would be powered from the energy stored in the main battery pack.
> 
> ...


Thank you. That seems very reasonable. Will check amperage on startup!!!


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## modifications (Nov 10, 2021)

oshw said:


> The 12V aux plug should be able to support a 12A continuous load.
> 
> It runs off of the large high voltage pack DC/DC converter when the car is not sleeping... So as long as the car is awake, any aux loads would be powered from the energy stored in the main battery pack.
> 
> ...


The 12V accessory port runs off of VCfront.

Everything runs off of one of the 3 VC's. There is VCright - VCfront -VCleft.

Each VC has MOSfets that control the 12V distribution of the entire car. This keeps Tesla from having to install fuses. If you short any VC 12V output - such as the 12 accessory port, then a MOSfet opens up and protects the 12V distribution. Even the 12V battery is fed by a MOSfet.

So....the 12V accessory port is not directly tied to the PCS High Voltage penthouse. It's not.

I would encourage everyone to either use the 12V accessory port or the 12V battery itself because you will then protect the PCS from shorts via the VC's.


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