USB and 12V power switching logic

[ZeeDoktor]

Does anyone understand how the USB ports and the 12V socket in the console are switched in a 2020 Model S? Specifically:
- How long until they turn off when the car is locked?
- Is that timeout configurable?
- Does camp mode or climate keep mode keep them powered?

Would be nice to be able to tweak those parameters. And perhaps even keep at least the USB ports powered at all times.

I've resorted to a 12V-5V converter powered via the CAN bus connector for a permanent connection, but that's no really elegant and requires a permanent cable running out from under the dash.

 

[ewoodrick]

Nope they aren't left on all the time, they are switched.
No you can't configure them.

I do believe that they stay on in some mode, like camp mode.

The ports that are connected to the entertainment computer are just like most computers and when it goes to sleep, it turns it off, that's how the car get the power consumption low. The other ports are switched as well.

Even the 12V port is switched off.

 

[vcor]

I did an extensive analysis (and timing) for a number of power connections (12v and 5v USB) for the S/X/3/Y in different modes: Accessory Power Guide 12v/5v – TeslaTap

It should answer all your questions.

 

[ZeeDoktor]

That is super useful, thank you! Looks like I did find the correct way to plug in the accessories I never want turned off using the diagnostic port on my 2020 S. I didn't really consider 1A (12W) to be the limit, although I don't think I've exceeded that running a pi and canserver off it. Probably exceeding that now with a 5G mobile AP though.

Presumably the diagnostic bus 12V line is powered from the 12V battery, considering it never turns off? Will equipment always running deplete the 12V battery? Or will the car detect a low 12V battery state and periodically charge?

 

[vcor]

Just about every power connection point, short of the battery itself, is run through electronic fuses that monitor the current and will shut off a circuit that pulls too much current. Software controls the limits for each circuit, and we've not seen anywhere the published limits. Quite a bit of my testing was at 1 amp, but that is likely not the limit. I did test the always-on power to the Model S DRNP control/display and when I pulled about 1.5 amps, it tripped. It took about 10 days to reset which was mildly annoying, but it didn't affect using the car. A reboot did not reset the fuse. Some connection overloads are re-enabled in an hour or two, like the 12v power plug, which can provide 12 amps (and 16 amps peak).

There is no concern about depleting the 12v/16v battery. It is always monitored and the car will automatically charge it back up from the HV battery.

 

[ZeeDoktor]

Now that we have access to service mode, is there a way to reset the e-fuses via any of the service screens?

 

[vcor]

Not that I've figured out. I wouldn't worry about it too much in less you're planning to overload a circuit. I've found that radar detectors and dashcams don't require enough power to trip an eFuse.

 

[ZeeDoktor]

Looks like I found a snag: The diagnostic port 12V went low in my 2020 Model S last night, had all the kit rebooted this morning. Your table shows it never loses power so that may not (or no longer) be true. Perhaps it was a glitch. Will confirm if it happens again.

 

[vcor]

It's possible Tesla changed the way it works between the 2016 S I tested and your 2020 S! Let me know if it happens again and I'll add some notes.

 

[krsgio]

It's possible Tesla changed the way it works between the 2016 S I tested and your 2020 S! Let me know if it happens again and I'll add some notes.

I looked at your site recently for advice but hard finding any specific info. I'm looking at the U3000 for my 2015 P85D but seems like both OBD and the speaker has constant power. Is there a pro/con to a dash cam that has parking mode but only has constant power seems like it will never enable parking mode and just continuously record?

 

[vcor]

I use the Blackvue 900 dashcam with always on. It detects car motion (or maybe uses the camera) so it goes into parking mode without a third line. I like it to keep recording while parked, but I use a lower frame rate so it doesn't consume the 256 GB of memory too quickly when parked. The newest Blackvues offer a third lead for ICE cars. For those dashcams with two power leads (typically yellow and red), I recommend connecting them together and using always-on power with an EV. ICE cars need a separate power-off connection to avoid running down the 12v battery - a non-issue with EVs.

Note that if you use sentry mode, most power points will act like always on when Sentry is running and you're parked.

 

[ZeeDoktor]

Ok so here's an update: The diagnostic port in my 2020 Model S loses 12V power after about 10 minutes when parked at home. With sentry mode active, it stays on. With the car plugged in, it stays on.

Hope this helps anyone else.

 

[vcor]

Yep, that matches what I found.

 

[ZeeDoktor]

one final detail: with the car plugged in AND CHARGING it stays on, once fully charged, it will turn off as if the car wasn't plugged in.