Become a fan of Slashdot on Facebook


Forgot your password?

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

Power Transportation

Tesla Model S Battery Drain Issue Fixed 239

Posted by Soulskill
from the acquitted-on-all-charges dept.
cartechboy writes "Does the Tesla Model S suck down power even when the car is switched off? Recently, a tweet to Elon Musk with an article saying so sparked the Tesla CEO's attention. He tweeted that it wasn't right and that he'd look into the situation. Then a few hours later, he tweeted that the issue had to do with a bad 12-volt battery. Turns out Tesla had already called the owner of the affected car and sent a service tech to his house to replace that battery — and also install a newer build of the car's software. Now it appears the 'Vampire Draw' has been slain. The car went from using 4.5 kWh per day while turned off to a mere 1.1 kWh. So, it seems to be solved, but Tesla may either need to fix some software, or start sending a few new 12-volt batteries out to the folks still experiencing the issue."
This discussion has been archived. No new comments can be posted.

Tesla Model S Battery Drain Issue Fixed

Comments Filter:
  • by von_rick (944421) on Friday December 06, 2013 @02:50PM (#45621163) Homepage

    " to a mere 1.1 kWh per day, while doing nothing.."

    - sorry, I am actually a Tesla fan (or would be, given the chance..) - but 1100w (per day) for doing sweet fuck all, presented as progress?

    it's stuff like this that makes me say, thanks, call me when you have the finished article.

    1.1kWh is equivalent to having a ~40W light bulb on. If you have a couple of circuits powered on, given it is a fully electric car with all kinds of gizmos built into it, this discharge rate is actually quite nominal.

  • by Anonymous Coward on Friday December 06, 2013 @02:55PM (#45621225)

    "1100w (per day)" ... whatever that means, it is wrong.

    1.1 kWh = 45 watts for a day

  • by silas_moeckel (234313) <(silas) (at) (> on Friday December 06, 2013 @02:57PM (#45621259) Homepage

    You do realize the thing does not have a key. Hell you can not even open the doors without the fob they are literally retracted into the car.

  • Re:4.5 kWh per day (Score:4, Informative)

    by Trepidity (597) <.delirium-slashdot. .at.> on Friday December 06, 2013 @03:07PM (#45621367)

    That's 4.5 kilowatt-hours per day. I.e. in a day, it draws 4.5 kWh of energy.

    A watt is a unit of power. A watt-hour is a unit of energy. 1 Wh = 1 W x 1 h. Similarly, 1 kWh = 1 kW x 1h. A 200-watt motor left on for an hour will draw 200 Wh of energy. A 200-watt motor left on all thetime will draw 200 W x 24 h = 4.8 kWh of energy per day.

  • Aux battery (Score:4, Informative)

    by Animats (122034) on Friday December 06, 2013 @03:10PM (#45621393) Homepage

    There's a 12-volt lead-acid battery in the thing to power the auxiliary systems. It's the same size as a regular automotive battery, but apparently is a sealed type, intended to last the life of the vehicle. Since it doesn't need to provide cranking power, a high-current battery isn't necessary.

    Tesla owners have been reporting 12 volt battery failures for months. Usually the charging system reports "12 volt battery failure", but apparently a partial failure is possible, where the aux battery is an energy drain but still functional.

  • by von_rick (944421) on Friday December 06, 2013 @03:17PM (#45621443) Homepage
    Wan't to completely turn the battery off? You sure can, but that clicker to open/lock the door won't work, nor would the security alarm. These are the first two things that come to mind. There might be many other essential things that you might have to do without.
  • by SternisheFan (2529412) on Friday December 06, 2013 @03:35PM (#45621617)
    Found this article from November 25, 2013. Three excerpts below...

    "According to Tesla, the car needs a constant flow of power to keep its computers and systems switched on 24/7, ready to boot up instantly when the driver gets into the car. (It's a popular myth among Model S owners that much of the vampire power goes to keep the battery warm during cold nights. This is simply not true.) According to Tesla, there is no thermal management of the Model S battery when the car is turned off and not charging--no matter how cold it gets."

    "Ironically, the Model S had very little vampire drain when it was first introduced. My owner's manual is based on the original software in the car. "When you're not driving Model S, the Battery discharges very slowly to power the onboard electronics," it purrs reassuringly. "On average the battery discharges at a rate of 1 percent per day. Unfortunately, the "sleep mode" software in those early cars triggered all sorts of glitches in the car's other systems. Eventually, the problems became so persistent that Tesla simply disabled the sleep mode. With sleep taken away, the vampires came out to play. And instead of draining 1 percent every 24 hours, the Model S battery suddenly began losing 5 or 6 percent of its charge every day. (In the case of 60-kWh cars like mine, it's closer to 7 or 8 percent.)"

    "So far I've run three overnight tests with the kWh meter. For each test, I charged the car up in the evening to its usual selected level (In my case, about 80 percent). Then I removed the charge plug. I allowed the car to sit unplugged overnight and on into the next day, until I needed to drive it. (Typically a span of 12 to 24 hours.) Before driving it, I plugged it back in to top off the vampire-depleted battery back to its original level. Then I checked the kWh-meter. Test results: The three tests showed vampire losses of 2.3 kWh in 17 hours, 1.9 kWh in 23 hours, and 4.2 kWh in 18 hours. Total vampire power lost was 8.4 kWh in 58 hours. That's an average of 3.5 kWh per day--roughly 25 percent lower than the losses I measured previously. I can't explain the wide variation in the vampire draw over the three tests. Clearly, more than three tests will be required to come up with an accurate figure. But it's clear to me that the new vampire-slayer software is pretty weak stuff. It's better than nothing, I suppose. 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. And it means that Musk's anti-vampire prediction has turned out to be one-quarter true in twice the time. Update 6.0, anyone?" []

  • by SternisheFan (2529412) on Friday December 06, 2013 @03:49PM (#45621711)
    Doh! I should have fully RTFA completely through :( Turns out it was the car's defective 12volt battery

    And so it looks like my vampire was indeed my car's defective 12-Volt battery

    But does the 12-Volt hypothesis explain why so many Model S owners reported similar problems on the various owner forums? Do they all have bad 12-Volt batteries?

    And what about the odd fact that most of the reported problems seem to be in 60-kWh cars? The Tesla spokesman told me that the 60- and 85-kWh batteries are identical, vampire-wise.

  • by AmiMoJo (196126) * < minus punct> on Friday December 06, 2013 @04:41PM (#45622127) Homepage

    Yes, but a mobile phone can't drive dual large displays with Nvidia GPUs

    My phone drives a full HD (1920x1080) screen with desktop class graphics, more than enough for what Tesla does. They should be able to power down their GPU and screen when not in use.

  • by bledri (1283728) on Friday December 06, 2013 @10:16PM (#45624325)

    Take SpaceX for example - where the fanbois refuse to acknowledge the problems the Falcon 9 has experienced and who also treat the Falcon Heavy as if it were a proven craft rather than vaporware.

    So you hate Elon Musk because you imagine that people (who are not Elon Musk) are not adequately upset by all the "problems" that Falcon 9 has experienced? Are you sure fanbois (nice ad hominem by the way) refuse to acknowledge the "problems," it seems to me you are blowing them out of proportion. What Falcon 9 problems are out of line for developing a completely new rocket, including engines? I'm not saying there haven't been problems and I know it took longer than they thought, but I don't see anything out of the ordinary in the course of developing a new rocket. Also, kindly list any comparable rockets that had fewer problems during their development and shakedown phases. Most currently flying rockets have had catastrophic failures during their development and service. The "worst" incident so far for the Falcon 9 was an engine failure, and it still reached orbit and deployed it's cargo - albeit in a lower than optimal orbit. Here is a sampling of some respectable rockets, from respectable companies having real problems:

    1. First launch of the Ariane 5 []
    2. Ariane 5 Mission Failure []
    3. Proton-M launch failure []
    4. Soyez launch failure []
    5. Progress fails to reach orbit []
    6. Taurus XL fails to reach orbit []
    7. Delta II launch failure []
    8. Zenit-3SL/ NSS-8 Sea Launch rocket vehicle failure []

    No rocket technology has ever been perfect right off the drawing board and most rockets flying today are using engines originally designed in the 60s and 70s. Those engines failed a lot during their early flights.

    The only currently inservice rocket (that I am aware of) that has not had an outright failure is the Atlas V. That thing is amazing, but it costs 4x as much to launch as a Falcon 9 even though ULA gets launch subsidies. Orbital Services' Antares also looks like a solid platform. Its first flight was originally planned to be in December 2010 (when it was called the Taurus II). Its first launch was actually late April 2013. Two and a quarter years behind schedule (which is about the same delay as the Falcon 9.) Yet it's a much less capable rocket than the Falcon 9, using "off the shelf" engines and therefore should have been easier to design and build. But it turns out that building rockets is hard, even for companies that have been doing it for decades.

    I want to be clear, I'm not bagging on any of the existing manufacturers nor their rockets. I just don't understand your animosity towards SpaceX, Elon Musk, and those of us excited that space flight is becoming less expensive.

    And I feel the same way about Tesla. I don't expect a car to be perfect. It seems like a damn cool car and most the people that own one seem more than pleased with it. As for this problem existing for quite a while, it sounds like Tesla addressed it once they where made aware of it.

    Facts aren't hate - except to the fanbois.

    If this has to be explained to you... well, then you're either among the fanbois or terminally clueless as to the world around you.

    You didn't list any actual facts and calling people fanbois and terminally clueless is pretty rude.

Q: How many IBM CPU's does it take to execute a job? A: Four; three to hold it down, and one to rip its head off.