Tesla phantom draw - surprising

[OVERKILL]

Saw this comment on Twitter and thought it might stir some stimulating conversation here:

That's roughly 30-60kWh/month consumed just being plugged in, which is significant for sure!

 

[ZeeOSix]

That's roughly 30-60kWh/month consumed just being plugged in, which is significant for sure!

Some heat and losses in any electronics with power applied. Plus I'd think the battery just sitting is slowly losing some charge, which would be made up if always plugged in. Kind of like a "Battery Tender" in use.

 

[OVERKILL]

Some heat and losses in any electronics with power applied. Plus I'd think the battery just sitting is slowly losing some charge, which would be made up if always plugged in. Kind of like a "Battery Tender" in use.

That's exactly it. Keeping the wireless communication alive, the battery at float...etc. I'm just surprised at the volume of power used for this process. There are roughly 720 hours in a month, so this is a constant draw of 42-83W, which is a fair bit more than your average laptop at idle, which leads me to believe that the float charge is likely the biggest consumer.

 

[Vercingetorix]

Open the garage door to the house and use it as a heater.

 

[brianl703]

Maybe it would be worth it to wire a water heater timer up to your Tesla charger to turn it off when it's not needed for charging.

 

[gathermewool]

That's exactly it. Keeping the wireless communication alive, the battery at float...etc. I'm just surprised at the volume of power used for this process. There are roughly 720 hours in a month, so this is a constant draw of 42-83W, which is a fair bit more than your average laptop at idle, which leads me to believe that the float charge is likely the biggest consumer.

1. You must have a nasty, huge gaming laptop
2. Your monthly figures are likely high, considering the Tesla shouldn’t be plugged in 720/month

 

[gathermewool]

Some heat and losses in any electronics with power applied. Plus I'd think the battery just sitting is slowly losing some charge, which would be made up if always plugged in. Kind of like a "Battery Tender" in use.

That’s one helluva battery tender!

 

[OVERKILL]

1. You must have a nasty, huge gaming laptop
2. Your monthly figures are likely high, considering the Tesla shouldn’t be plugged in 720/month

The guy in question, Dr. Chris Clack, has had his parked and plugged in for the last few months because he hasn't been driving it, hence the observations on consumption.

Those monthly figures would actually be low, as they don't include charging, since the car isn't going anywhere.

Most of my laptops have had 90W adapters.

 

[JHZR2]

That's exactly it. Keeping the wireless communication alive, the battery at float...etc. I'm just surprised at the volume of power used for this process. There are roughly 720 hours in a month, so this is a constant draw of 42-83W, which is a fair bit more than your average laptop at idle, which leads me to believe that the float charge is likely the biggest consumer.

Big packs with parallel cell groups need to have pretty significant balancing, which burns off energy from high cells, to allow the low cells to charge higher. It does consume energy, and I can see that a car like a Tesla, which has tons of small parallel cells is more wasteful in thst regard than a car with larger format cells and fewer in total. Then, just like any vehicle that doesn’t shut down its modules and computers, it will continue to guzzle energy. A Tesla, essentially a computer on wheels, likely has a bunch running all the time...

 

[gathermewool]

The guy in question, Dr. Chris Clack, has had his parked and plugged in for the last few months because he hasn't been driving it, hence the observations on consumption.

Those monthly figures would actually be low, as they don't include charging, since the car isn't going anywhere.

Most of my laptops have had 90W adapters.

Yea, but we’re not talking about charging. We’re talking about time at full charge.

You said idle, not peak PLUS a large fudge factor (ie, 90W). Seriously, check your true idle draw. It’s low. My gaming laptop will also switch between its graphics card and integrated graphics, depending on load.

 

[JimPghPA]

Someone told me that Tesla vehicles have cameras that monitor all the surroundings, and can be set up to produce a verbal warning to "please step away from the vehicle" if someone is staying very close to it. I do not know if that is correct, but if they have such a security system, that could explain part of the power consumption. Also if it has those cameras it might be recording all that video.

 

[JeffKeryk]

Someone told me that Tesla vehicles have cameras that monitor all the surroundings, and can be set up to produce a verbal warning to "please step away from the vehicle" if someone is staying very close to it. I do not know if that is correct, but if they have such a security system, that could explain part of the power consumption. Also if it has those cameras it might be recording all that video.

That's Sentry mode and is only on if you configure it. Vandals were keying the cars and thieves were breaking in looking for laptops and such.
So Tesla quicklly programmed Sentry mode. If someone is too close for a period of time, the info screen lit up with a warning and the cameras start recording.
Again, it is not on by default; you configure it to come on when at work or whatever.

Sentry Mode

 

[Kiwi_ME]

My Kona Electric lost about 1% (of 64 kWh) when sitting unused for 5 weeks. All the battery really had to do was charge the 12V battery for 20 minutes each day. I don't have any telematics thankfully.

 

[OVERKILL]

Yea, but we’re not talking about charging. We’re talking about time at full charge.

Right, but my point was that the car was plugged in all month, it just didn't go anywhere, so the 720 hours figure would be reasonably correct given he noted a draw of 1-2kWh a day. Most people leave them plugged in when they aren't using them.

You said idle, not peak PLUS a large fudge factor (ie, 90W). Seriously, check your true idle draw. It’s low. My gaming laptop will also switch between its graphics card and integrated graphics, depending on load.

I think we are getting away from the point a bit, which was simply that the systems in this vehicle draw significantly more power than a laptop sitting relatively idle/not doing too much. The reference laptop having a 90 or 120W adapter really isn't all that germane, since we have the actual consumption figure, I was just trying to make it somewhat relatable; provide a point of reference.

 

[gathermewool]

Lol, sorry for contributing to the OT. I get your point.

I haven’t read up on it since this thread started. How prevalent is this? Im surprised by the parasitic load, but are those of you in the know surprised? Does the self-drain of the batteries slow as SOC lowers?

Regardless, I wouldn’t say even this amount of draw is prohibitive if you drive your car daily, which I for one would. With a 15-20 min drive I’m an ideal candidate for a small, low-range EV, like an older Leaf. Trust me I’ve thought about it. I‘m simply not ready to take the plunge, and I think there are a lot of people on the fence with me. I don’t mean the “gas fo’ life!!!” folks, but those who are waiting for the tech to mature just a liiiittle bit more, which means lower costs (without subsidies, even though I’m for them), safer batteries and predictable supply chains over the next 20 years.

 

[MrPlow]

It's rather strange how some battery devices drain out so quick while others don't drain fast at all. I have an Anker power bank that hasn't been used in 2 years. It still has the exact same charge level today as it did years ago. Virtually no drain. My Sony a6300 camera's batteries, even when not installed in the camera, will drain 20% a week. All 3 of them. My Canon batteries might lose that much in a year of sitting idle, if that.

On the other hand, it does seem like devices designed for rapid charging suffer from "phantom draw". I have a large set of EGO battery equipment for my property maintenance business. Those things can charge incredibly fast -- probably equal or better per unit of energy rate than a Tesla super charger. But, the batteries will drain down to 50% power or so in a week or two, then they level off from there and drain much slower. That's just the batteries themselves and them not driving any computer hardware.

 

[Job]

That's Sentry mode and is only on if you configure it. Vandals were keying the cars and thieves were breaking in looking for laptops and such.
So Tesla quicklly programmed Sentry mode. If someone is too close for a period of time, the info screen lit up with a warning and the cameras start recording.
Again, it is not on by default; you configure it to come on when at work or whatever.

Sentry Mode

They definitely have a sentry as I set them off frequently just being by my own car without touching the Tesla in any way. Warnings go off, and I see inside the screen and it says "recording." I find that very intrusive on me. I really don't like to be recorded by a machine while getting into my own car, for no reason. I guess it isn't illegal.
On the Volt, the owners manual states it is best to leave the battery at the minimum, depleted, state when leaving the car unused for long periods of time. I forgot how long they were talking about, months I guess. This seems contrary to what is being said here. The depleted state still has the buffer, which is like 1.5 kwh.

Maybe it said store at 30% charge or less, I don't have the car now. I know I have bought some power tools and they were somewhat old stock, the batteries have like one bar left, it's supposed to be best for them to store that way. So it couldn't have been drawing anything to make it over a two year period.

 

[OVERKILL]

Lol, sorry for contributing to the OT. I get your point.

I haven’t read up on it since this thread started. How prevalent is this? Im surprised by the parasitic load, but are those of you in the know surprised? Does the self-drain of the batteries slow as SOC lowers?

Regardless, I wouldn’t say even this amount of draw is prohibitive if you drive your car daily, which I for one would. With a 15-20 min drive I’m an ideal candidate for a small, low-range EV, like an older Leaf. Trust me I’ve thought about it. I‘m simply not ready to take the plunge, and I think there are a lot of people on the fence with me. I don’t mean the “gas fo’ life!!!” folks, but those who are waiting for the tech to mature just a liiiittle bit more, which means lower costs (without subsidies, even though I’m for them), safer batteries and predictable supply chains over the next 20 years.

I'm surprised by the amount of parasitic draw, not that it's there, you expect some, particularly given how "connected" the vehicle is, it is just more than I anticipated.

If the car had an 85kWh battery and that discharge rate is constant (I'm sure it is not, it likely tapers off considerably and I'm sure there are functions that are reduced or shutoff depending on SoC) you'd significantly deplete the battery leaving the car disconnected for a month. This is an important "lightbulb" moment, or should be, because that differs considerably from what we are used to with gasoline vehicles.

 

[MrPlow]

I'm surprised by the amount of parasitic draw, not that it's there, you expect some, particularly given how "connected" the vehicle is, it is just more than I anticipated.

If the car had an 85kWh battery and that discharge rate is constant (I'm sure it is not, it likely tapers off considerably and I'm sure there are functions that are reduced or shutoff depending on SoC) you'd significantly deplete the battery leaving the car disconnected for a month. This is an important "lightbulb" moment, or should be, because that differs considerably from what we are used to with gasoline vehicles.

Word. It does seem to put a little bit of a dent in the "cleanliness" electric vehicles are supposed to be promoting. Having a car that pollutes by draining on the power grid, just by being parked, does not seem ideal at all. Even if it has to take pictures of suspicious dogs and swap spit over the air with Tesla Motherbrain, a smartphone could handle that task load for quite a long period using a battery with an order of magnitude less energy.

EDIT: Elon is probably using parked Telsa cars to mine bitcoin in the background. LOL

 

[Kiwi_ME]

That's a bit overly dramatic, but not unexpected when a bias exists. Tesla having a particular problem does not mean all EVs have a problem. The last thing a typical EV driver needs to worry about is the traction battery discharging by itself.

I don't care much about the Model 3 but I understand they have placed the 12V DC-DC convertor inside the battery casing so that it can operate either all the time or at least more frequently without having HV present outside that housing. Perhaps that results in a higher drain, who knows? It certainly doesn't affect owners of the many other EV brands.

In others that I'm aware of the DC-DC unit is separate and is only active when the main contactor inside the battery housing is closed. While parked the EV will use the 12V battery to handle telematics and other chores. The 12V battery is charged either when the traction battery is on-charge, or on a schedule, often either daily or every 4 hours. On older models of Leaf it's only when the car is powered-on for driving, so there are occasional issues with that design.

While the 12V battery is charged it's provided with a constant voltage of about 14.6 V, exactly as in an ICE car. Once the battery is full, very little current will flow and the main battery only has to support the operating overhead for the remainder of the period, perhaps about 200 W.

While driving, in the case of Hyundai at least, the 12V system is maintained at around 13.1 V to ensure that the 12V battery is not discharged for the duration.