What Phantom Drain??

[jasonh4451]

My 2018 used to lose about 1% per day but now I’d say it’s 1-2% per week if I leave it alone in my garage.

 

[Dave EV]

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]

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The difference is that Tesla is pinching pennies to use outdated Intel Atom processors which aren't even being made anymore.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.

 

[AlanSubie4Life]

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]

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.

 

[user212_nr]

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.

 

[Pete_in_FL]

Just got back from 43 day trip, fully charged midrange Model 3 lost 20 miles of range in that time.

Looks like software updates solved that problem.
.

 

[AlanSubie4Life]

Just got back from 43 day trip, fully charged midrange Model 3 lost 20 miles of range in that time.

Looks like software updates solved that problem.
.

Yeah it seems way better than it used to be.

 

[theothertom]

Just got back from 43 day trip, fully charged midrange Model 3 lost 20 miles of range in that time.

i hope you didn't charge to 100% and leave it for 43 days.....

 

[theothertom]

I just got back from a 7 day trip. I had charged to 80% and when I got back, the car still said 80%. No sentry or app checks, etc.

 

[Candleflame]

i might add here that sleepyness has been improved with the last (or one before) update.
The car falls asleep extremely quick when woken up via the mobile app now.
Rather than trying to do all the things like it might do after a drive or a prolonged wakeup i.e. opening the doors the car will often fall asleep within <1min now.
Before this process would usually take 20-30min after wakeup. Possibly as it was charging the 12V battery.
It seems the car will not charge the 12V battery now unless it has an extended opportunity.

 

[Zoomit]

i might add here that sleepyness has been improved with the last (or one before) update.
The car falls asleep extremely quick when woken up via the mobile app now.
Rather than trying to do all the things like it might do after a drive or a prolonged wakeup i.e. opening the doors the car will often fall asleep within <1min now.
Before this process would usually take 20-30min after wakeup. Possibly as it was charging the 12V battery.
It seems the car will not charge the 12V battery now unless it has an extended opportunity.

I've seen the same. This is great progress. Phantom drain, which at one time absorbed a lot of the oxygen in these forums, really is a thing of the past. Most new owners probably don't even realize what it is.

But there still are ways to burn down the battery unwittingly. I wish Tesla would provide an option for a "high drain alert" that could be activated when the Sentry mode or cabin conditioning is in heavy use. Similarly, it would be great to be able to adjust the cabin overheat protection from the app, so both the Sentry mode and overheat protection could turned off remotely.

 

[AlanSubie4Life]

I wish Tesla would provide an option for a "high drain alert" that could be activated when the Sentry mode or cabin conditioning is in heavy use.

Yep. For trips to remote areas, etc., it is annoying to have to remember to turn off Sentry, etc. (And it can have severe consequences if you forget for a few days - can’t make it back to a Supercharger!) It would be great to be able to turn on an automatic warning on the screen when exiting the vehicle, that would remind you that standby consumption will be high, with a list of contributors, and a one-click option in the pop up to turn them all off (and have the defaults remain - so a one-time turn off).

Great that the phantom drain is so improved (seems by at least a factor of 3) - definitely seems to have greatly reduced the posting about it here.

 

[rrolsbe]

Do we have any evidence that this is on in sleep mode? I am familiar with picture of the windshield camera heater being on in snowy weather (and the radar heater would be similar I assume)...HOWEVER, I am not aware that we have correlated that these things are on while in sleep mode.

To my knowledge (and it is vague and confused, tbh), I recall looking at this with my FLIR thermal camera and finding that the cameras, parking sensors, and the windshield heater did NOT show up as thermal signatures when the car was sleeping.

However, I could envision a situation where the Tesla monitored the temperature in sleep, and woke up more often to go to idle to do some preventative defrosting in these areas, from time to time...which would have the same effect, and result in more time spent in idle mode.

But the big question I have is when the contactors are open, do these accessories actually run? I'd be slightly surprised if they did - could be a lot of extra wear and tear on that 12V battery. It's knowable, though! Someone just needs to check it. I could, I suppose...but can't find where I left my thermal camera right now. I know it's around somewhere.

To your point, more frequent wakeups due to cold would still result in higher standby losses, even if those losses only happen in idle mode, of course. So it doesn't really change your point.

And I still want to see those 12V battery monitor captures, especially in cold weather! Would be very informative.

For reference, here is a capture from my car, showing a two-hour charging window from midnight to 2AM, where the battery went into a maintain mode (~13.4V) for most of it because it did not need charging, followed at 1:30PM by a trip to get some coffee (it stayed awake for about 40 minutes after I got back since the voltage was low enough to make it worth it), followed by a wakeup around 10PM which was initiated by me opening the door and putting stuff in the car (you can tell it didn't need to wake up since the voltage had not dropped far enough). It's very informative!

You'd definitely be able to identify a change in sleeping behavior - and if those mentioned accessories ran in sleep the voltage would drop a LOT faster in sleep mode. If not, you'd see less drop between cycles, but more frequent wakeups to idle to operate the warming features.

View attachment 618995

I agree that the sleeping power usage is between 5 and 7 watts which is just over 5KWH/month. The problem is the power required to top off the 12V battery is between 200 and 250W because of all the subsystems that are drawing power while the car is awake. A smart charger could easily deliver the continuous 5 to 7 watts of power required while the car is sleeping and not require anywhere near 200+ watts; however, the last time I tried using a smart charger for that propose, the car still woke up to top off the battery and stayed awake for four to eight hours (even though the 12V battery did NOT need to be topped off). Using the bluetooth battery monitor, I can see Tesla has made major changes since that time. My M3 currently wakes up every 16 to 18 hours and stays awake for aprox two hours to top off the three year old 12V battery. If the 12V battery was new, I suspect it would not wake up nearly as often. Since many changes have been made to the firmware, I should probably perform the Smart Charger test again. Has anybody performed such a test recently? I currently try to charge the traction battery during the two hour period where the car is topping off the 12V battery (wish there was a charging option that only charged while the car was awake).