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What Phantom Drain??

Dave EV

Active Member
Jun 23, 2009
1,694
1,131
San Diego
Honestly, I'm pretty happy if vampire draw is only 5W on average now.

1%/day is significantly more than that and not a number I was particularly pleased about - that's what the Model S/X typically drew and the Roadster was even worse.

Tesla might be able to get that lower, down to 0.5-1W maybe, if they can isolate and optimize the entry system radios and cellular radio systems, when wake up the other systems as necessary based on activity.

But at this point I'm more concerned about extra cycles on the 12V battery and the wear and tear on that than the energy consumption. Have bigger vampires in the house that are crazy (have you seen the amount of power a typical HVAC crankcase compressor heater pulls just keeping things "warm" when the system isn't in use?
 

user212_nr

Active Member
Aug 26, 2019
1,407
740
US
It would likely not be hard for them to respec the car to use less than 1W in sleep, and then make it happen with appropriate engineering and hardware changes to the Bluetooth receivers, etc. And voila.

An iPhone 12 has about 10 Wh and can last for 65 hours playing music. That equals 0.15 W and it has a more active cellular connection than does the Tesla (Teslas seems to go into cellular-sleep mode and wake every so often to check if it is needed).

When Tesla is running off the 12v battery, it is not a car but a computer. I can't think of any "car" functions that it does, except charge the 12v which it wouldn't need to do if it used less power. Battery cooling, etc, are only done just after leaving the car.

The difference is that Tesla is pinching pennies to use outdated Intel Atom processors which aren't even being made anymore. Its got a lot of similarity to their eMMC failure - they pushed to save money everywhere, but with computers you get what you pay for.

Intel cuts Atom chips, basically giving up on the smartphone and tablet markets

They probably figured that Tesla has such a big battery that they don't need to use more expensive smartphone chips, but its annoying obviously. At some point in the future, they will hopefully figure out how to buy and use previous-gen smartphone chips which are made in abundance and no longer fit for sale in a new smartphone.
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,395
11,275
San Diego
have you seen the amount of power a typical HVAC crankcase compressor heater pulls just keeping things "warm" when the system isn't in use

Yes! I throw the breaker on mine in the winter, and give it a day to warm up again. It is between 40 and 60W. Really pretty ridiculous that they can’t figure out a more elegant solution to that problem.
 

Dave EV

Active Member
Jun 23, 2009
1,694
1,131
San Diego
An iPhone 12 has about 10 Wh and can last for 65 hours playing music. That equals 0.15 W and it has a more active cellular connection than does the Tesla (Teslas seems to go into cellular-sleep mode and wake every so often to check if it is needed).

When Tesla is running off the 12v battery, it is not a car but a computer. I can't think of any "car" functions that it does, except charge the 12v which it wouldn't need to do if it used less power. Battery cooling, etc, are only done just after leaving the car.

The difference is that Tesla is pinching pennies to use outdated Intel Atom processors which aren't even being made anymore. Its got a lot of similarity to their eMMC failure - they pushed to save money everywhere, but with computers you get what you pay for.

Intel cuts Atom chips, basically giving up on the smartphone and tablet markets

They probably figured that Tesla has such a big battery that they don't need to use more expensive smartphone chips, but its annoying obviously. At some point in the future, they will hopefully figure out how to buy and use previous-gen smartphone chips which are made in abundance and no longer fit for sale in a new smartphone.
Good point - certainly the microprocessors in today's battery powered electronics do a great job of sipping energy. One wonders why they couldn't use similar technology for at least the "always on" portion of the car. It definitely should be possible to get the average quiescent power draw under 1 watt.

Yes! I throw the breaker on mine in the winter, and give it a day to warm up again. It is between 40 and 60W. Really pretty ridiculous that they can’t figure out a more elegant solution to that problem.
Yeah, unfortunately this doesn't work if you have a heat pump in the winter that you need to run. Still, there's a large part of the year that we don't need to run the heat pump and I suspect 24 hours is quite a bit longer than required to avoid issues.
 
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user212_nr

Active Member
Aug 26, 2019
1,407
740
US
Good point - certainly the microprocessors in today's battery powered electronics do a great job of sipping energy. One wonders why they couldn't use similar technology for at least the "always on" portion of the car. It definitely should be possible to get the average quiescent power draw under 1 watt.

The "always on" portion is the MCU (infotainment computer) which is basically a linux (popular alternative to Mac and Windows) computer. Linux supports ARM (smartphone type) processors, so its no problem software-wise.

The barrier is most definitely cost, especially in 2018 when the MCU-2 was launched, though it isn't clear exactly what that cost is/would have been. Using ARM processors on computers is becoming a trend now, so its just a matter of time before it comes to the Tesla MCU.
 

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