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What Phantom Drain??

tg27

Member
Mar 24, 2019
29
20
NY, NY
As most of us have experienced, phantom drain is real but can be controlled. My 2018 Model 3 SR+ (now totaled by a friend) lost about 1% each day while parked. My brand new 2021 Model 3 LR AWD keeps surprising me - it barely loses anything each day (knock on wood!)! As with my previous Model 3, I turn off Sentry and Wifi when I remember but this new car stayed at 82% for 2-3 days while parked in the cold. Bigger battery on a LR - possible reason? Better batteries? Whatever the reason, I hope it stays this way. TG
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,371
11,232
San Diego
As most of us have experienced, phantom drain is real but can be controlled. My 2018 Model 3 SR+ (now totaled by a friend) lost about 1% each day while parked. My brand new 2021 Model 3 LR AWD keeps surprising me - it barely loses anything each day (knock on wood!)! As with my previous Model 3, I turn off Sentry and Wifi when I remember but this new car stayed at 82% for 2-3 days while parked in the cold. Bigger battery on a LR - possible reason? Better batteries? Whatever the reason, I hope it stays this way. TG

Would be great news if this actually is the case for 2021 models.

As has always been said, there is really very little reason for the phantom drain. It stems primarily from an estimated 5-7W load (~500mA) on the 12V battery all the time when in sleep mode in vehicles to date, which is likely entirely unnecessary, as the car is doing very very little in sleep mode. 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.

But we'll see. It is very likely completely unnecessary, and it's just a matter of time before Tesla fixes this issue. I'd be kind of surprised if there is an improvement on 2021 vehicles though. A 12V battery monitor would be the easiest way to tell (decay time of the 12V battery voltage would be much longer if there has been a large improvement in sleep current, and the car could go several days between each idle cycle).
 

Zoomit

Active Member
Sep 1, 2015
2,180
4,083
SoCal
Would be great news if this actually is the case for 2021 models.
This is the case for my 2018 Model 3 LR.

This past summer I routinely saw just over 1% use per week. (About 1% loss every 6 days.) This was with Sentry off, Summon readiness off, not touching the car, not opening the app, and monitoring via TeslaFi.

Oh, and the car was unplugged. The HORROR!
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,371
11,232
San Diego
This is the case for my 2018 Model 3 LR.

This past summer I routinely saw just over 1% use per week. (About 1% loss every 6 days.) This was with Sentry off, Summon readiness off, not touching the car, not opening the app, and monitoring via TeslaFi.

Oh, and the car was unplugged. The HORROR!

Yeah, I think they have tweaked it a bit to sleep more reliably. And it's not THAT bad. I have no idea whether it used to be worse - I get the sense that it was. Still, that result works out to the 5W average drain which is pretty high, imo (implies that the 5W number I quoted above is probably a bit high). It is totally unnecessary as far as I can tell - the car isn't really doing anything in sleep mode! Just a matter of time before it's fixed, is my guess.

I'm not sure mine has ever been quite that low; I end up closer to 2% every 6 days I think for my 2018.

5W really adds up! That's $13 a year or so in electricity.

Anyway, would be interesting to see some 2021 data from a 12V monitor.
 

theothertom

Member
May 9, 2020
276
161
South Carolina
My 2020 hardly has any phantom drain. I don't have sentry on, or any 3rd party apps, and I always try to manually turn off climate control as I exit the car. And I don't check it with the Tesla app.
 

skgolf91

Member
Nov 21, 2019
161
81
NJ
My 2020 model 3 in the garage only lost like 3-4% in about a month in November. That's with me checking maybe 3-4 times with wifi on but sentry off. On the other hand, 2018 model S in Switzerland lost almost 1% a day back in March at the airport parking!
 

EV Promoter

Member
Nov 30, 2019
334
937
Europe
A My brand new 2021 Model 3 LR AWD keeps surprising me - it barely loses anything each day (knock on wood!)!
I do completely confirm, didn't got the chance to leave it alone for, say, 3 days or more, but max for 2 days.
I reckon a 0.5 km loss per day (much better to evaluate in km/miles than %, lot more precise), which on 535 km gives a % of the total charge that calculators shows with the exponential, too many zeros...

It become an appreciable drain only if you leave the car plugged in.
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,371
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San Diego
It become an appreciable drain only if you leave the car plugged in.

Makes no difference actually. Leaving the car plugged in just means you don’t lose much range since it gets replenished periodically. And heat runs from the wall. Etc. But makes no difference, fundamentally, to vampire drain. It does not affect sleep behavior. It is easy to verify this.
 

tivoboy

Active Member
Jun 12, 2018
1,549
3,360
palo alto, ca
Is the 5-7 watt load taking into consideration the battery management conditioning that is required when the temps are either very cold or high? I find I do lose a bit more daily/nightly in the winter months out here, when the garage can get to 35-40 degrees F. I was just away fro the longest time since getting the car and it really only lost 1 MILE a night, couple nights seemingly none, then a couple nights 2-3. I started with 200 miles on the battery and returned 21 days later with 175 on the battery.
 

EV Promoter

Member
Nov 30, 2019
334
937
Europe
Makes no difference actually. Leaving the car plugged in just means you don’t lose much range since it gets replenished periodically. And heat runs from the wall. Etc. But makes no difference, fundamentally, to vampire drain. It does not affect sleep behavior. It is easy to verify this.
I don't like to waste energy, if i can pull off the plug and avoid unuseful consumption, i'll do.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,371
11,232
San Diego
I don't like to waste energy, if i can pull off the plug and avoid unuseful consumption, i'll do.

But it does not actually save you energy to unplug unless you charge somewhere for free somewhere else. That was my point. You are not stopping the car from using energy - it uses the same energy plugged and unplugged to do what it needs to do. The plugged/unplugged status really makes no difference!
 
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jjrandorin

Moderator, Model 3, Tesla Energy Forums
Nov 28, 2018
8,083
8,946
Riverside Co. CA
I don't like to waste energy, if i can pull off the plug and avoid unuseful consumption, i'll do.

Its still used either way, though... I think thats @AlanSubie4Life 's point. Whether you plug it in or not doesnt change how much it uses, just where it uses it from. If it comes from your cars battery, you need to put that back in at some point.

EDIT: It looks like alan and I were posting at the same time, so I ended up repeating his message.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,371
11,232
San Diego
Is the 5-7 watt load taking into consideration the battery management conditioning that is required when the temps are either very cold or high? I find I do lose a bit more daily/nightly in the winter months out here, when the garage can get to 35-40 degrees .

In short, no. Though the conditions needed to make that happen are quite extreme. There’s really nothing it does to condition the battery (obviously we are not talking about explicit battery conditioning from the app here) as far as I can tell unless it is something super extreme. And if it were doing something it would not be in sleep mode. The 5-7W is a sleep mode number. (And that number is a guess, as I made clear - but it is in the ballpark...I need to get my current measuring loop!)

I live in Southern California so my ability to figure out how this works is very limited.

But I suspect that when the car is sleeping it won’t run the windshield camera heater either, and various other things that use energy. Someone can probably confirm. It would be easy to figure out.
 

EV Promoter

Member
Nov 30, 2019
334
937
Europe
But it does not actually save you energy to unplug unless you charge somewhere for free somewhere else. That was my point. You are not stopping the car from using energy - it uses the same energy plugged and unplugged to do what it needs to do. The plugged/unplugged status really makes no difference!
If you are talking about the vampire drain per se, i'm with you, but if the car does "things" when you're plugged, and it does, and the consumption clearly goes up, that's different.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,371
11,232
San Diego
If you are talking about the vampire drain per se, i'm with you, but if the car does "things" when you're plugged, and it does, and the consumption clearly goes up, that's different.

We’d have to discuss specific examples, but other than the special pre-conditioning of the battery (that behavior changes depending on plugged status I think? No idea - I am in SoCal), I cannot think of an example of something the car does that is different when plugged vs. unplugged.

(The preconditioning *would* be different - it would result in more regen when driving that you would have had if you had not done it. But that comes at a cost (a difference in plugged vs. unplugged energy use).)

Maybe there are other examples?

As far as what the car does when plugged in - it runs the AC-DC converter, etc. When it is charging (or using shore power to run accessories) only. That has some losses. But you were going to realize them *anyway*, the next time you plugged in to charge (you’ll be charging for longer, the next time you charge, if you have not been leaving the car plugged in). And the car will run the heat, etc., even when not plugged in.
 
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skgolf91

Member
Nov 21, 2019
161
81
NJ
Makes no difference actually. Leaving the car plugged in just means you don’t lose much range since it gets replenished periodically. And heat runs from the wall. Etc. But makes no difference, fundamentally, to vampire drain. It does not affect sleep behavior. It is easy to verify this.

I agree that it doesn't make a difference. My model 3 is plugged in and only very little amount in 4 weeks
 

camalaio

Active Member
May 28, 2019
1,483
2,086
Vernon, BC, Canada
this new car stayed at 82% for 2-3 days while parked in the cold

I'd caution all of us from drawing any optimism from this - reported SoC can swing wildly in the cold. It could've actually been draining down slowly, but slightly warmer each time you checked resulting in still reporting the same SoC. External analysis on these cars is very annoying due to things like this :p

I'll echo the above points though, even on earlier models drain can be quite small. It's just hard to get there and you throw that all away the moment it's cold anyways. There's some things they could do with hardware changes to lessen the drain, but the main drains were more of a software "problem" (quotes because some reasons are "features"). If anything, the newer Model 3s might require more standby power than before for things like the new radar heater and general thermal management stuff post-drive with the heat pump system. Those aren't phantom drain per se, but they do ultimately use energy.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,371
11,232
San Diego
for things like the new radar heater

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.

IMG_8526.PNG
 
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KenC

Active Member
Sep 4, 2018
3,458
3,147
Maine
Did the OP factor in seasonality? Parked outside, my 3 loses 4x as much in cold Winter than it does in hot Summer. I lose about 0.1miles/hr in Summer, according to Stats. In the depths of Winter, I can lose 0.4miles/hr. And when looking at the spectrum of drain from Stats users, you see some people lose alot more. Of course, we don't know if they have Smart Sentry or other big energy users on at home.
 

tivoboy

Active Member
Jun 12, 2018
1,549
3,360
palo alto, ca
Did the OP factor in seasonality? Parked outside, my 3 loses 4x as much in cold Winter than it does in hot Summer. I lose about 0.1miles/hr in Summer, according to Stats. In the depths of Winter, I can lose 0.4miles/hr. And when looking at the spectrum of drain from Stats users, you see some people lose alot more. Of course, we don't know if they have Smart Sentry or other big energy users on at home.
Pretty much my experience too mostly with cold. I haven’t tracked it anywhere near as closely other than capturing start, middle, end data. I’d like to understand what the battery fluid pump uses for energy as well as the most likely heating of the fluid. Heating is more energy dependent than cooling from my limited understanding.
 

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