Video: Tesla Model S Vampire Drain After 27 Cold Days of Being Unplugged


Tesla Model S owner Bjorn Nyland tests out the vampire drain “issue” with the Model S.

Bjorn's Model S Vampire Drain Summary

Bjorn’s Model S Vampire Drain Summary

In this video, Bjorn leaves his Model S 85-kWh for 27 days in the cold.

Upon exiting the Model S, Bjorn notes there’s 90% charge.  On returning, the battery displays a cold reading of 70% charge.

This amounts to a loss of less than 1% per day, which basically dispels the myth of the Model S chugging down electrons while in sleep mode.

Over the course of 27 days, Nyland’s Model S went from 347 km of charge to 246 km.

As Nyland states:

“Average temperature outside ranged from +2°C to -2°C. But as you can see, the temperature was +8°C inside the parking lot. That was because the parking lot was undergoing repairs and was heated up.”

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49 Comments on "Video: Tesla Model S Vampire Drain After 27 Cold Days of Being Unplugged"

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I wouldn’t say it dispels the myth, for a few reasons:
– This measured electricity consumption when not plugged in, which could be very different than when the vehicle is plugged in and in sleep mode.
– Numerous other owners of Teslas have reported significant power consumption when plugged in, with energy monitoring devices (versus state of charge displays)
– The vehicle may be more aggressive at keeping the battery under a certain temperature rather than keeping the battery above a certain temperature.

I hope that the Tesla vampire power draw issue gets fully resolved, but this datapoint isn’t enough to dispel the myth for me. I’m keeping my fingers crossed though, as the car is otherwise such an elegant design and piece of machinery.

“…this datapoint isn’t enough to dispel the myth for me.”

/implying you believe in myths

Haha. Hey, some guy in Texas said he shot big foot… You never know. 😉

But okay, I would call it substantiated facts more than I’d call it a myth. 🙂

A software patch solved the problem a few months ago, along with replacing some 12V Pb-acid accessory batteries (post a month or so ago, either on here or Autoblog green).

Tesla has said that the battery pack is not, nor has it ever been, heated/cooled when unplugged and the car is turned off. When it is plugged in, then my understanding is that the heating/cooling system is active, which will suck more electrons than the SOC would show.

Now to the more important question… did Bjørn get engaged/married in Thailand? In that case, congratulations!

They got engaged for sure 🙂 . In video they showed the rings

First, if you believe it’s a myth, that is saying you don’t believe it (or believe it to be a fabrication).

Secondly, the “myth” goes something like “you lose X% per day when not plugged in”. Where X is a distressing high number. Vampire loss is about when the car is NOT plugged in.

I agree that one should look at the battery behavior when plugged in and in sleep mode but that’s a completely separate issue. However, I don’t believe there is an issue there. At least I haven’t seen it with my MS.

Finally, myth is completely the wrong word to use. People have reported significant vampire loss in their cars – those are real reports from actual owners. Recent firmware updates have significantly improved the vampire loss (though with startup times at it comes out of deep sleep). Plus recent updates have also increased the use of “shore power” when plugged in.

Your last point is really concerning to me. Increased use of shore power is not an acceptable solution. These cars should not be using so much energy just sitting there. That is a HUGE design flaw. The functionality they’re performing is admirable but the design was not well thought out if the power consumption is so high.

I agree. The Model S is energy-efficient only compared with full-size luxury ICE cars. It is an energy hog compared with other EV’s. Part of this is understandable in that to offer a high range, a very heavy battery pack must be included which takes much more energy to propel.

But just sitting there doing nothing for 27 days used more energy than my i-MiEV’s battery pack contains! I parked my i-MiEV for 2 months and returned with no obvious loss of energy. If any other EV had such high vampire losses as the Model S, the range loss would be unacceptable.

Huge is your term – we’re talking about well less than a light bulb’s worth of the electricity. Probably around 10 cents worth of power in a 24 hour period. An ICE idling for a 10 minutes to warm up on a cold morning is far worse.

8.4kWh in 58 hours AFTER updates to address vampire loss is WAY more than a light bulb’s worth of electricity per day.

Extended to the whole fleet, the article reads:
” A 25-percent improvement means that the 20,000 Model S cars now on the road will only waste about 70 megawatt-hours of power a day, down from 90 MWh.”

70 megawatt-hours wasted per DAY! Whereas the Leaf and Volt have ZERO vampire draw. Even if they cut power draw by another 90% over this, it’s still 7 MEGAWATT-hours every day wasted, that’s not insignificant by any measure.

Ah, but if you don’t have an active liquid thermal management system and your expensive battery pack dies far earlier, the energy and carbon loss due to having to replace your battery pack is likely to negate any difference in vampire drain.

It’s not an either/or choice. I own a Volt, it has an active thermal management system AND has no vampire draw issues.

All these articles seem to have loaded phrases in them,like ‘myth’, or ‘cold weather’..

I’ve got some news: mid 40’s temperature is ‘hot’ around here.

I’d like to see some information regarding operation overnight at -14 to -18 degrees centigrade.

Tesla is probably averse to doing these things because their UMC’s crap out at those temps, as in Norway for instance. They try to say their stuff is ‘too precision’ for Norway’s electricals, but then Canadians who live in upper Ontario or Quebec throw a monkey wrench in their plans stating they’ve also had trouble.

The heating/cooling system on the Model S does NOT operate when the car is both unplugged and off.

The vampire losses are coming from undisclosed sources, though one source has been keeping the Pb-acid accessory battery charged…seems odd that it would have one…

David Noland’s car had a weak 12V battery which caused the car to feed power to it. Problem is that to do so it ends up waking up too much and running battery heating which increases the vampire use.
After his 12V was replaced the vampire was severely rduced,

Yes, the vampire problem is still there, but 5.8 at least made it significantly less than a 120V socket can supply which means that cars plugged in won’t lose charge. Still, I don’t believe Tesla has stopped working on it, which is of course very important.

Agreed. Did anyone notice if it was mentioned what was the AVERAGE temperature while parked and what was the extreme low? This info should be available on a car 2 years old but it is just available bits and pieces. So what was the final temperature of the battery, and how much did the range decrease immediatedly after turn on before battery heating was completed? The video stopped before this happened.

Clarksoncote: Just because you want factual information, as do I, don’t let the “Tesla Uber Alles” crowd get to you. Some of those guys even swear blind devotion to Musk and they’re not even Tesla customers yet as we are.

Thanks for the reminder Bill 😉

I thought he got married, nice rock though, and Thailand is the place to get it.

I really don’t get what’s the big f-ing deal. If you don’t drive the car for 27 days, just plug the damn thing in when you get home from vacation.

Actually range didn’t drop by 20% but 30%: it was left at 347 miles and upon return it was 246 miles which would be a 30% drop. Since 30% of 85KWh of battery capacity =25.5 KWh it would appear idle draw is pretty close to the 1 KWH per day it is supposed to be down to after the latest software update.

People really do have a hard time with percentage vs. percentage point. It’s such a common mistake in articles and news that you have to wonder if it’s even teached anymore…

“Taught”. 😉

Haha… thank you for educating me. English is my third language so there is always something new to learn (or old things that I have been taught 😉 once upon a time that I need to remember) 😛

What happens when you leave it in an exposed airport parking lot, in 0 deg F weather, unplugged for 3 weeks?

my thought exactly, after this winter..

Why would you? If you’re going to be gone that long, take a cab or bus or get a lift from a friend or family member.

I have a MS 85Kw/h for 3 months, software 5.0, my vampire drain in 24 hours is 1 to 2 miles, I live in Washington DC., with underground parking garage with temperature varies from 30F to 42F.

How can it be a vampire drain if it isn’t plugged in?


Apparently the Model S behaves far nicer with the later software than it did initially. Now, it will be interesting to see the daily drain in very cold weather such as 0-10 degrees fahrenheit (-14 to -18 deg C).

I’m under the impression that the drain suddenly greatly increases once a certain very low temperature is broken, but until someone actually does a test sorta like this video did (although we dont know the temperature), at least by me it is still to become known.


Does your Roadster lose any range at all? I am curious. You have a Volt too, right? Does it lose any range?

Uh, The roadster typically loses very little but its hard to say today, which is going down below zero fahrenheit, so I’m plugging it in, not to charge it, but to heat the battery. I’m fearful of a $50,000 battery freezing so I’m going to warm it up for a few hours. The heater is ‘around’ 900-1000 watts, i’m not sure since the touch screen lies and I’ve only measured it at 110 volts at home and from what the charge point thing says in public, which is a very scotch reading usually. The volt seems to lose nothing, impossible as that may seem, even in cold weather. As you’re aware, the Volt doesn’t tell you what its doing. All I know is that it uses 3 kwh more to charge in the deep cold of winter than in the springtime. (12 vs 9.5 kwh) So I’d imagine its heating the battery for those extra 2.5. I’m also guessing that when you start driving, the first thing it does is use its own juice to heat the battery, unless the engine is running and then it will use engine heat to warm the battery. kwh. No change in charging efficiency… Read more »

er, I mean 110 volts is 30% more kwh , than 220 volts ( less efficient).

Actually I should say 26 degree weather. At 10 degrees it isn’t an issue because the engine will start, but if I deliberately keep it off, by either running out of gas, or it being in a sweet spot of 26 degrees (hot enough to keep the engine off but cold and moist enough to HAVE to run the defroster 100%), then I get 6 miles worth of travel. I think someone somewhere said the heater is over 6 kw, which warms water either for the cabin or the battery itself. . Add the big blower on high and other accessories and youve got 7 kw. So it takes only a bit over an hour for the heater to drain the big battey all by itself.

Interesting info. Thanks!

Czar, some electronics is connected to the battery in the car. No need to connect to mains for waste to occur.

I don’t know what all the fuss is about. For about fours years I worked on all types of battery and electrical systems – automobile, truck, boats, RV, huge trucks, and tractor, electical systems, alternators, generators, troubleshooting battery drain, shorts all kinds of electrical systems – it’s what put me through college. (I took one year of intense automotive technician engineering knowing I would need a job to pay for my regular BA degree) Anyway, any automotive or battery technician will tell you that “Most vehicles draw some battery current when the key is off.”This is typically due to the clock and the internal memory of engine computers, body-control modules and radio presets. Altogether, they draw a very small amount of current. Fifty miliamps would be a safe upper limit for this, although many vehicles will draw less. If you’re not sure, look up the correct rating in the service manual.”

In my opinion – no biggie – Tesla will find the problems – or a sharp automotive technician – it is an easy fix with some focus.

There’s a side issue with the S that may be seen reading the Tesla Motor Club blogs. Apparently if you don’t have the UMC on, but plugged in, it will deaden the 12 volt auxilairy battery, and its a bit of a bear for service. .

Bill, Roadsters destroy the pack if left for about 5 months. Not the best design..

That’s true, but Dan, please come up with a replacement battery pack for the roadster, cheap. And while you’re at it, since the old one is “Not the Best Design”, make the new one about 220 kwh at the same weight. I’m getting sick of this 220-240 mile range in the spring time and want more like 900. It may not be the best design, according
to you, but it is superior to the model S’s performance to date.

When I purchased my roadster I had to sign an ‘agreement’ that I would plug the thing in every night there were temperature extremes, or when the battery state-of-charge got low.

Well, who’s the idiot that buys a car an doesn’t use it for 5 months?!?

Felix, the drain in Tesla cars is so high that it would flatten a normal car battery in a few hours. It’s literally like leaving the high beams on with incandescent bulbs ALL THE TIME. With the Roadster you are saddled with 100watt constant waste that can never be turned off. With model S it has an additional optional sleep mode where it’s reduced to 1/4 or so.

It’s criminally incompetent engineering.
They should have learned the lesson from the roadster at least but they made the exact same mistake with model S.

Martin Eberhard (the founder of Tesla Motors) actually made a public issue out of how wasteful his Roadster was in this matter. And iirc it was even much worse back then in 2008ish. There was a cooling pump that used 100watt that they just left on forever when the car was off… if the pump wasn’t just part of the 100watt waste then it would have been 200watt constant waste back then.
Yet somehow these aspects were ignored in the electronics department for Model S.

It’s funny how success and gross incompetence can go hand in hand like that.

While I sympathize with Eberhart, your information is quite out of date at this point. While my 2011 Roadster did have a continuous loss, a very quick software update shuts down the circulator pump after 5 minutes in normal, and 1 1/2 minutes in range mode. In range mode it also minimizes needless cooling fan usage, by letting the temperature rise as the thermostat in an ICE car does.

The roadster still has bugs regarding improper regeneration, and (here we go with another charging issue), a design defect caused grounding fault during EVSE negotiation, but in general it is good enough that most people would consider it a ‘completed design’ for a low-volume product. Me included.

Dan, Thank you for taking the time to reply. And thank you for the extra detailed information. Very interesting what’s going on. Long time ago, when RVs were getting more popular us battery/electrical system technicians spent an inordinate amount of time tracking down “vampire loads” and “shorts” that drained the big batteries. But the 100 watt factoid that you bring up is very large load to be un-noticed at the design stage. This tells me that the components are added piecemeal without any systems integration or commissioning. Long time ago this happened with RVs as they added different components and after market equipment to satisfy the needs of the actual vehicle. But it sure wasn’t 100 watts worth. Interesting.

If at all possible (financially and facilities-wise), my next car will be a Tesla.

However, as an engineer by education and bound by efficiency, I cannot figure out why Tesla, doing everything else so well, cannot seem to get a grip on the vampire losses (car is off, not plugged in). There does not appear to be any legitimate excuse for it, particularly since I have not heard about any other EVs having such extensive power drains when not in use and unplugged!

Has anyone ever received a straight answer on this?

Tom, I work in the energy efficiency and building systems business. There are many analogous scenarios in my industry niche whereby vampire loads and losses contribute to inefficiencies on total system performance. More and more it was due to not commissioning the final system for total tuning. We see it all the time at the edges of performance. What’s interesting it does take “software” patches and fixes to capture those anomalies in a complex system. It also takes a lot of logging and monitoring ahead of time to capture stuff – which can be very expensive man-hours. Thus many systems get to production model mode without complete commissioning. In many ways, the Tesla is a complex system. And this complex system has new and different components perhaps not totally integrated and commissioning yet for true production stage. But Ford and Chevy Volt are complex system too and I have not heard about vampire problems with those models.

Fellow EV readers – Because I worked on electrical systems and batteries for 4-5 years while in college and live next to the Tesla plant, my plan is to ask some of the actual people who design and assemble the Tesla car itself. Drains in Cars Once again, I recall encountering the “un-accounted for energy drains” or “vampire losses” on many regular cars, RVs, tractor trailer systems. Our customers would come into our “garage:” begging for help. My team and I would spend hours reading the single line circuit diagrams of cars and tracking down the so-called vampire losses; although in my day we didn’t use that term. Generally speaking, we discovered that after the car is turned off the battery is still considered a mini-storage powerplant to power up many devices – little cooling fans, small little spinning motors, radios and such. And it appeared to us that during the assembly of the car the single line was not followed exactly or rather the component was installed at the latter part of the assembly. I recall taking apart a car to locate a short or find an alternative wiring system approach in order to find the energy drain. I… Read more »
Fellow EV Readers – I research other blogs and it appears the issues are: 1. the 12 Volt batteries and accessories and drain on the 12 volt battery – Tesla needed to send a firmware update in order that the software would shutoff those accessories after a short time of normalizatioin so the 12 Volt battery wouldn’t drain down. 2. the Over the Air firmware updates 3. the extra electronics and accessories in the Tesla itself require DC electricity to keep power on 4. Similar issues emerged with Leafs for some owners. Generally speaking it appears all the new accessories in the EV cars are causing battery drain on both the existing standard 12 Volt battery (lead acid) and also on the EV Lithium battery systems that are used to power the powertrain. I recall when working on standard ICE cars and their battery/electrical systems that this was also the case. The emergence of added accessories caused battery drain on the standard 12 volt battery system. However, in the case of the ICE car the alternator constantly charge the 12 Volt battery. And there are voltage regulators, condensers, and capacitors used to regulate the high voltage output of the alternator… Read more »