Power drain while idle (Vampire Load)

[nleggatt]

Nitpicker's corner: If you're going to use the term "idle" here, I think the Model S has a nice edge on an ICE vehicle.

When I read this I was like, "What the heck is brianman talking about!?" then I re-read what I wrote, what was I smoking?! I can't even think what word I meant to type, must have been kids in the background making me loose train of thought... hmm. what I meant though was "standby"

 

[tezco]

In my experience leaving the car unplugged for longer periods, rather than allowing it to top itself up each day, may result in some modest savings. I have measured 10% higher losses over the first day, after the car is charged and about 5% higher losses over the first three or four days, after which the per day losses stabilize. However, this is based on a single observation and should be repeated to confirm that this result was not affected by other factors.

This is not borne out by my data. Fortunately we had some heavy snow around here last month that caused me to leave the car in the garage for some protracted periods so that I could test out this hypothesis.

 

[brianman]

When I read this I was like, "What the heck is brianman talking about!?" then I re-read what I wrote, what was I smoking?! I can't even think what word I meant to type, must have been kids in the background making me loose train of thought... hmm. what I meant though was "standby"

Heh. I don't smoke but sometimes people think I'm on something (when I'm not).

 

[JRP3]

Nitpicker's corner: If you're going to use the term "idle" here, I think the Model S has a nice edge on an ICE vehicle.

Nitpicker redux, the thread title is "Power drain while idle", and idle does mean inactive, so...

 

[CarGuy1340]

Idle Losses = 'Dirty' car

Anyone see the report on WhatsupWiththat about the idle losses making the Model S emit more CO2 than a ICE? Tesla needs to fix this.

 

[brianman]

Nitpicker redux, the thread title is "Power drain while idle", and idle does mean inactive, so...

Titles can be wrong and confusing too.

For every vehicle I've ever owned, driven or ridden in the term "idle" has never referred to sitting in the garage with no human nearby for hours. (Except if somebody leaves a running vehicle unattended, I suppose.)

But you're right. YMMV. I'll start using the term "idle" to mean "regenning down the face of a mountain" just to keep it interesting.

 

[JRP3]

Since a moving car of any type is not "idle" of course that would be a misuse of the word "idle", which predated automobiles. Maybe with the advent of EV's the term will eventually cease to be associated with a car that is running but not moving. An ICE that is parked with the motor running is "idling", a parked EV is "idle".

 

[Todd Burch]

Anyone see the report on WhatsupWiththat about the idle losses making the Model S emit more CO2 than a ICE? Tesla needs to fix this.

Yes..."WhatsupWiththat"...the world's source for accurate technical information. That's utter nonsense.

 

[brianman]

Since a moving car of any type is not "idle" of course that would be a misuse of the word "idle", which predated automobiles. Maybe with the advent of EV's the term will eventually cease to be associated with a car that is running but not moving. An ICE that is parked with the motor running is "idling", a parked EV is "idle".

I think you'd be hard pressed to find any car on planet earth that is strictly "not moving".

 

[JRP3]

The final nit has been picked. :biggrin: Well done.

 

[brianman]

The final nit has been picked. :biggrin: Well done.

/hug

Current terminology preferences aside, my original point was/is that terminology matters in this space. Part of the compelling nature of EVs is when you're stuck in traffic at a standstill or rolling at like 5mph. I think the "vampire load" name fits better than "idle" does for the "overnight in a garage" losses.

 

[RichardC]

This is not borne out by my data. Fortunately we had some heavy snow around here last month that caused me to leave the car in the garage for some protracted periods so that I could test out this hypothesis.

View attachment 21565

Thanks Tezco, while the rate of power loss is clearly not primarily controlled by the duration of the time unplugged, the wide variance apparent in your measurements begs the question of why your losses over a couple of days would be 50% higher in some instances than in others? Was your car subject to wide variations in temperature?

 

[neroden]

Well they say on their web site 1% per day parked. We are far from it.

Rrrrrgh. Again, they didn't used to say that. This is a big error on the part of the marketing division... they need to stop advertising things they can't deliver yet.

 

[EarlyAdopter]

Well they say on their web site 1% per day parked. We are far from it.

Keep the faith. 1% per day is absolutely real, as anyone who had v4.1 with sleep mode enabled knows, or still knows if they ignored the firmware upgrades since and kept sleep mode. It'll be back for all soon enough, I'm certain.

 

[artsci]

I lost less than 5 percent while parked for 24 hours at the airport. Not at all a concern.

 

[jweinstein]

Silencing the Vampire - A troubling element of the vampire losses on our Model S was the electric motor soundtrack which I heard at all times, whether the car was on charge or not, and which continued even when the car was unplugged. While it was a relatively quiet motor, it was running all the time and seemed to be somewhere in the front half of the car. Picking up on a suggestion earlier in this thread, I have taken to turning the car off (on the main screen) whenever parking it, and this past weekend measured the power consumed to keep the battery topped up. During the first 24 hour period I turned off the car without getting in and was pleased to hear that the motor noise stopped. The next daily top up used 4.3 KWHrs of electricity. While this is better than the 5.3 KWHrs/day that I measured over the course of the month of February (with the version 4.2 software) it was not much better than previous tests with the version 4.3 software. More troubling was the fact that the pesky electric motor was turned on again by the charging cycle and continued running after the charging was complete. I powered off the car again and silenced the motor and left it for another day. This time the top up used 4.03 KWHrs of electricity, which is still inexcusably wasteful, but is better than I have previously seen, and the electric motor remained off after the charging was complete.

Have others noticed the electric motor noise and/or seen any benefit from manually powering down the car whe leaving it? Does it make any difference whether you sit in the seat when powering it down (I had the impression that a number of additional systems are powered up whenever you are in the driver's seat)? The car is indoors with the temperature around 9 degrees C (or around 48 degrees F). By way of reference 5.3 KWHrs/day corresponds to around 220 Watts of continuous power consumption, 4.3 KWHrs/day corresponds to around 180 Watts of continuous power consumption, and 4.03 KWHrs/day corresponds to around 168 Watts of continuous power consumption.

Richard,

Were you ever able to silence the vampire? I am having the same pump noise from the front of my car, charging or not. It seems to run constantly.

Josh

 

[apacheguy]

I am having the same pump noise from the front of my car, charging or not. It seems to run constantly.

I, too, experience a pump noise coming from the front half of the car. Although it is more intermittent and does not run constantly.

Just heard it this morning while the car was off and not charging. Ambient temp was 70 F. Any ideas on what it could be? Is it circulating the battery coolant even though it isn't warm enough?

 

[jerry33]

I, too, experience a pump noise coming from the front half of the car. Although it is more intermittent and does not run constantly.

There are several possibilities:

1. Brake actuator pump. This one should be intermittent.

2. Battery coolant pump. Could be continuous depending upon the charging level.

3. Inverter/motor coolant pump. Shouldn't really happen when the car has been off for a while.

 

[markb1]

1. Brake actuator pump. This one should be intermittent.

For the parking break? Such a design seems flawed, to me. If the battery gets too low to support this, the car will start to roll.

 

[JRP3]

Not the parking brake, the vacuum assist for the power brakes.