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Why Tesla Cars Aren't Bricked By Failing Batteries 362

Posted by samzenpus
from the not-do-fast-now dept.
itwbennett writes "Don't believe recent claims made by a blogger that non-functioning batteries in the Tesla Roadster cause the electric cars to be bricked, says IDC analyst Sam Jaffe. 'Here's the primary fact that the blogger in question doesn't understand: the Tesla battery pack is not a battery,' says Jaffe. 'It's a collection of more than 8,000 individual batteries. Each of those cells is independently managed. So there's only two ways for the entire battery pack to fail. The first is if all 8,000 cells individually fail (highly unlikely except in the case of something catastrophic like a fire). The second failure mechanism is if the battery management system tells the pack to shut down because it has detected a dangerous situation, such as an extremely low depth of discharge. If that's the case, all that needs to be done is to tow the vehicle to a charger, recharge the batteries and then reboot the battery management system. This is the most likely explanation for the five 'bricks' that the blogger claims to have heard about.'"
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Why Tesla Cars Aren't Bricked By Failing Batteries

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  • battery vs cell (Score:5, Insightful)

    by Anonymous Coward on Thursday February 23, 2012 @06:36AM (#39134907)

    There seems to be a fundamental misunderstanding of the terms 'battery' and 'cell'. A battery is the collection of cells. So a Tesla could be bricked by a failed battery but it is tolerant to a failure of individual cells. This is not surprising.

  • Re:battery vs cell (Score:2, Insightful)

    by Tsingi (870990) <graham DOT rick AT gmail DOT com> on Thursday February 23, 2012 @08:03AM (#39135265)

    There seems to be a fundamental misunderstanding of the terms 'battery' and 'cell'. A battery is the collection of cells. So a Tesla could be bricked by a failed battery but it is tolerant to a failure of individual cells. This is not surprising.

    Semantics.

    Statements like that one are what this piece is about. AC either hasn't read the article or is a troll. This is exactly what it explains can't happen, and statements like the one the AC made are the kind of propaganda that the misinformation campaign spreads.

  • Re:battery vs cell (Score:5, Insightful)

    by geekmux (1040042) on Thursday February 23, 2012 @08:14AM (#39135319)

    There seems to be a fundamental misunderstanding of the terms 'battery' and 'cell'. A battery is the collection of cells. So a Tesla could be bricked by a failed battery but it is tolerant to a failure of individual cells. This is not surprising.

    There seems to be a fundamental misunderstanding of the terms 'brick' and 'won't start'. I know it's clearly far too late as I stare at a page of comments that look like "this" or 'this', but let's at least try and keep the IT geek terms out of the automotive industry, no matter how many "Intel Inside" bumper stickers you may run across.

    Might I remind all of what has happened to the term "hacker" in mainstream media. I don't need or want to be labeled as a criminal for simply trying to get my damn car to start in the future, which is likely the more accurate terminology no matter what is under the hood. Mechanics probably have no idea why people keep talking about a "brick" either, for the automotive shop doesn't stock "mortar" for repairs.

  • Re:battery vs cell (Score:4, Insightful)

    by EasyTarget (43516) on Thursday February 23, 2012 @08:30AM (#39135397) Journal

    So a Tesla could be bricked by a failed battery but it is tolerant to a failure of individual cells.

    No.. A Tesla cannot be bricked by a failed battery. It is merely a Tesla with a flat battery.. nothing more.

    Terminology here is quite important, the negative word 'bricked' is being used to try and transfer a operator failure (running out of battery) into a criticism of the product itself.

  • Re:battery vs cell (Score:5, Insightful)

    by BasilBrush (643681) on Thursday February 23, 2012 @08:41AM (#39135445)

    which is why Tesla requires owners to shell out $40,000 to REPLACE a completely discharged battery.

    It's bunk. If the battery pack is completely discharges, tow it to a charger, plug it in and wait. Then reset the battery management system, and you;re good to go.

    What kind of cretin believes that a discharged rechargeable battery requires replacement?

  • by robbak (775424) on Thursday February 23, 2012 @08:53AM (#39135487) Homepage

    How about this: the $40K has been made up from whole cloth by a blogger we already know is ignorant of the facts surrounding electric cars.

  • Re:battery vs cell (Score:5, Insightful)

    by fuzzyfuzzyfungus (1223518) on Thursday February 23, 2012 @08:59AM (#39135535) Journal
    It depends on what you mean by 'discharged'. Some battery chemistries do, indeed, die(or at least suffer severe capacity damage) if 'discharged' in the sense of 'take a bare cell, connect to a resistor of suitable value until current drops to zero'. The high performance lithium cell chemistries certainly are rather touchy, and even humbled old lead-acid will start to sulfate if left discharged like that for any length of time... However, because that is a trivially bad thing, such batteries are hidden behind a management circuit that will delclare the battery 'discharged' and refuse to provide any further output well before the physically destructive discharge level is hit.

    If Tesla actually built multi-kilodollar battery packs that allow their cells to run below safe discharge levels, somebody at Tesla needs a beating. If, however, this story is 'rechargable battery pack must be recharged and possibly recalibrated after running 'flat' as defined by the management circuit!', then the writer needs a beating.
  • Re:battery vs cell (Score:4, Insightful)

    by masternerdguy (2468142) on Thursday February 23, 2012 @09:12AM (#39135577)
    I suppose all electronics can be bricked by removing batteries then.
  • by Golden_Rider (137548) on Thursday February 23, 2012 @09:47AM (#39135743)

    Yes, the claim seems to be actually true: http://jalopnik.com/5887265/tesla-motors-devastating-design-problem [jalopnik.com]

    When not plugged in or when plugged in with an unsuitable extension cord, the battery can run completely dry within a few days (one claim say that the battery can go from full to 50% within a week, another claim on that website says that according to Tesla, one car went from 4% to dead in a week).

    I guess most people who buy an electric car will say "well duh, I know that when I have my car not plugged in, eventually the battery will be empty. I'll just have to recharge then". But I guess also most people will not know that the battery will be DEAD, as in "you have to get a new one, this one's DESTROYED" when it goes to zero charge.

    Having a battery which can be destroyed in a matter of days if the car is not plugged in is a pretty big issue. An issue people really need to be made more aware of. Go on holiday and leave your Tesla at home? You better ask a friend to check every couple days if the car is still charging. Or what if you park your Tesla at an airport, plan to leave it plugged in there for a week, but on the first day you're gone, some kid unplugs the car "for the lulz"?

  • Re:Tow? (Score:3, Insightful)

    by d3ac0n (715594) on Thursday February 23, 2012 @10:25AM (#39136059)

    This entire article is stupid. Essentially they are making the technical claim that the car isn't REALLY "bricked" because "Only one or two cells are really bad, and they can be fixed."

    Here's the problem with that argument: If a handful of bad cells in a battery pack cause the pack to be unusable, AND the car to be un-tow-able AND require the ENTIRE PACK to be replaced at a very high cost, then for all intents and purposes the car IS "bricked".

    Techno-sementic arguments about the precise definition of "bricked" don't matter AT ALL. The damn thing won't work anymore without paying an arm and a leg to have it shipped back to a tesla service center and have the ultra-expensive pack replaced. It's Bricked.

    Ultimately this points to two issues:

    1) Tesla's battery management system is woefully inadequate and hasn't gone through proper real-world testing. As the darling of EV lovers and large portions of the government they were given a pass (and large amounts of taxpayer money) and QC wasn't done properly.

    2) ANY vehicle power system the requires a complete core unit replacement part by simply leaving the vehicle sitting unused for a "normal" amount of time in "normal" environmental conditions is NOT ready for prime-time. If this is the state of EV's across the market, and not just a tesla-specific issue, then EV's are in no way ready for the mass market. Niche market, yes, mass market, NO.

    Hopefully this will turn out to be just a Tesla problem and they can get it fixed quickly.

  • Re:You know... (Score:2, Insightful)

    by Methuseus (468642) <methuseus@yahoo.com> on Thursday February 23, 2012 @10:40AM (#39136227)

    Some injection systems required multiple thousands of dollars of repair after being run dry. I know that's not quite the same amount, but those cars I know about cost less than $30k new...

    Lesson: If you pay over $100k for something, learn the limitations it has. Expensive things require more maintenance, usually.

  • Re:battery vs cell (Score:3, Insightful)

    by BasilBrush (643681) on Thursday February 23, 2012 @11:51AM (#39136903)

    And the original article is obviously wrong. Read the second one.

    The Tesla roadster uses laptop batteries. Are laptops bricked if you leave them unplugged for a few weeks? No, of course not.

    Now theoretically, if you removed the battery management system, and directly drained the cells, then chemically you would damage the cells. But that's one of the fundamental purposes of the battery management system (in your laptop battery and in the Tesla.) Power drain is cut off from the cells well before they are completely drained.

    Tesla themselves point out the mistakes in the blogs claims. And there are no such "bricks". From the description given they just need recharging, and the battery management system resetting. Of course it's possible that they are faulty cars, and need servicing. Cars do get faults. But there is no design flaw, whereby a Tesla Roadster left without power for a few weeks needs a complete replacement of it's batteries. It's just bollocks.

  • Re:battery vs cell (Score:5, Insightful)

    by BasilBrush (643681) on Thursday February 23, 2012 @11:59AM (#39136995)

    No they don't. I've recharged and powered up laptops which have not been used for years. They still work fine. And the Tesla Roadster uses laptop batteries.

    Litium-ion CELLS, if they had a resistance put across them so they completely drained would be damaged. But batteries have power management systems that that cut off supply long before they are drained. Of course cells have internal drain, but it's so low that you're talking years and probably a couple of decades before that completely drains a cell.

    Tesla themselves have pointed out the story is false. The blogger got his facts wrong. A blogger being wrong - why is anyone surprised by that?

  • Re:battery vs cell (Score:5, Insightful)

    by bws111 (1216812) on Thursday February 23, 2012 @12:47PM (#39137567)

    That 'can not be towed' statement is really dumb. Lots of illegally parked cars have wheels that won't turn (transmission in park, parking brake on). Yet they still manage to tow them quite successfully. Jack up the car and put dollies under the wheels. What could be more 'traditional' than that? Sounds like this guys 'traditional means' involve 20ft of rope and an old pickup truck.

  • by yurtinus (1590157) on Thursday February 23, 2012 @02:00PM (#39138559)
    Having RTFA'd, it is a negative opinion piece full of half truths and misinformation. That article is a horribly blatant attempt to discredit the vehicles from somebody who does not understand the underlying technologies. It needs to be taken as an opinion piece - there are zero references on his five examples (it's simply a chat with a service manager), and he is stating things as fact which simply aren't.

    First: yes, there are cases with batteries where they can be discharged to the point where the cells themselves are damaged and cannot be recharged. This is the case with *most* battery chemistries and is not going away any time soon. The blogger calls this a "Devastating design problem" when it is simply a part of the technology, like not storing your fuel cans near the furnace or leaving fuel to sit in a carburetor. There is a pretty clear warning in the car's manual not to let the battery voltage flatline for long, our intrepid blogger even provided a a PDF file with that page out of the manual. It states that the battery must be charged immediately if the charge level falls to 0% and has a great deal of information on the care and feeding of the battery.

    Even if we take the five failed battery packs as truth, that is 0.2% of vehicles with an issue - an issue that in each example was due to the owner not charging the vehicle with one possible exception. His extension cord example could present a possible issue with the Tesla chargers. A typical cheap "heavy duty" extension cord will have 16 gauge wires, which over that distance is going to have some noticeable resistance. I don't know the current draw of the battery, but if it is expecting to pull 10 or 20 amps, the charger will see a significant voltage drop and likely cut off the charging (unless it has a "trickle charge" mode, dunno...). If the vehicle didn't report that it wasn't charging (or inaccurately reported it was), then I could see this being a design issue. I'll also note that this particular example did not state whether the customer had to pay for the repair.

    What it comes down to is all electrical systems have ways they could be improved. That doesn't make this a devastating problem, it is simply an aspect of this class of vehicle that the owner needs to pay attention to. This blogger has a bone to pick or wants to stir the pot with a sensationalist report. Apparently it's working, after all, we both read his article :P

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