back to article BMW recalls 1.3m motors over fire risk

BMW has recalled more than a million cars across the globe because a battery cable they contain might malfunction. It it did, it could cause a fire, the company said. Some 109,000 vehicles in Britain could be affected by the wire flaw. The issue relates to the covering of a battery cable in the boot of 5 and 6 Series BMWs …

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  1. min

    aah..

    ..when i heard about this yesterday, i was hoping that it was some brilliantly insidious plot by Japanese manufacturers to cripple the german car industry (wel, BMW anyways) at some as-yet-undisclosed time in the future. all it turns out to be is a darn wire.

    boo.

  2. Ogi

    Could someone explain to me...

    Why modern cars seem to like sticking the battery at the back? In all the older cars I've known/used the battery was as near to the engine as possible. This is due to the huge starting current required when cranking.

    At 12V the wires are really thick and short. Surely sticking the battery at the back results in even thicker wires needed? (to stem the resistive losses through the increased length).

    What advantage did putting the battery in the back achieve?

    1. Geoff May

      Re: Could someone explain to me...

      More space in the front of the car for various plastic mounts to make it even harder to get to the light bulbs to change them.

    2. Piro Silver badge

      Re: Could someone explain to me...

      Perfect weight distribution! Probably.

      Actually, the guy talking about the plastic covers was likely closer to the real answer. Just make the thing obtuse and awkward, and you'll end up taking it to the deal every time.

    3. Anonymous Coward
      Anonymous Coward

      Re: Could someone explain to me...

      Weight distribution. BMW have been doing this for a long time. My 325i SE had the battery in the boot 20-odd years ago.

      1. 20legend
        Happy

        Re: Could someone explain to me...

        But that is a pretty pointless exercise considering the small difference that moving the battery from front to back makes to weight distribution, versus the unevenly distributed weight of driver, passengers and luggage.

    4. Evil Auditor Silver badge

      Re: Could someone explain to me...

      @Ogi: no, longer wires do not need to be thicker, just the same a short wires.

      My, equally subjective, view: classic car, front engine, battery in the boot; almost new car with rear midengine and battery in the front. Reason for both of them is weight distribution.

      1. Ogi

        Re: Could someone explain to me...

        They would have to be thicker, if you want the same overall resistance when you stick all that current down them.

        Keeping all things the same, longer wires will have more resistance (is it a linear relation? I'm not sure), so if you want to keep the same overall resistance you'd need thicker wires (or better conducting metal in them).

        I guess I was wrong about it being a new thing then. The oldest car I know that had the battery at the back was the BMW 8 series in the 90's (Along with the 90's Porsche 944 Turbo, but I believed that was in order to make more space in the engine bay for the turbo piping).

        Out of curiosity, which classic car do you have? It would be interesting to see where the idea of sticking the battery in the back came from...

        1. Evil Auditor Silver badge

          Re: Could someone explain to me...

          Yes, but the same overall resistance is not the issue, the heat is the problem since the insulation or the copper itself could melt. And therefore just the wire cross section needs to be of certain size to accomodate the high current during cranking.

          Lotus Elite - but I doubt that this is where the idea came from.

          1. Ogi

            Re: Could someone explain to me...

            Surely though P = I^2 * R.

            Assuming the motor's power requirements are the same, then having a longer wire will result in higher resistance, which will increase the heat output of the wire for a given current, no?

            And a Lotus? Nice! I've always been partial to the Esprit myself, but they are expensive to get a hold of! (Plus there is an issue of space living in London, otherwise I'd love to have a little classic car collection going!)

            1. Evil Auditor Silver badge

              Re: Could someone explain to me...

              Yes (again), the total heat output of the wire will increase. However, since it is also longer the increased power dissipation is distributed over an equally increased surface leaving the longer wire with the same surface temperature as the short one. Obviously, you will lose more energy over the longer wire but the termal stress on the wire will be the same for any length with a given diameter.

              Ah, the Esprit looks nicer! But the Elite's (type 75) handling is slightly better. Well, they are not necessarily expensive to get hold of but to keep running... Mine isn't ;-)

        2. TeeCee Gold badge

          Re: Could someone explain to me...

          Obvious example is the original Mini (1959). No space under the bonnet for it.

          The MGB (1962) has the battery behind the seats, forward of the boot. Originally two six volt ones, then a single twelve volt. The reason here is that when it came out, they couldn't get a single 12v unit that provided sufficient cranking amps to turn over the engine reliably and two 6v units wouldn't fit in the front. The fact that the "B" series V8 engine that required that cranking power never got made is beside the point. The resulting unnecessary pig's ear, of a car having a bonnet mostly full of fresh air and a battery in the back, is just typical of the british car industry....

          1. Evil Auditor Silver badge

            Re: Could someone explain to me...

            @TeeCee: from time to time MG built some really nice cars (which usually looked like they originated one or two decades ago). Unfortunately, they deserve the price for the worst overall range of models and can happily share it with Rover. Love my MG, just the same.

    5. Joe Montana

      Re: Could someone explain to me...

      Can't speak for BMW, but Jaguar first started putting the battery in the rear with the V12 models, because there was no space in the engine bay...

      Having the battery in the rear can improve (very slightly) weight distribution...

      But is also helps keep the battery dry, there is often a lot of moisture flying around the engine bay as its fairly open to the elements.

      1. Cupboard

        Re: Could someone explain to me...

        Didn't the original mini have the battery in the boot to save space?

        1. some vaguely opinionated bloke
          Thumb Up

          Re: Could someone explain to me...

          Yes indeed, except the Traveller/Countryman/Clubman Estate, that had them MGB-style under the back seat.

          Still confuses people as you reverse up to them to jump-start their car...

          1. Anonymous Coward
            Anonymous Coward

            Re: Could someone explain to me...

            The Xsara Picasso has the battery in a compartment under the front passenger seat. This actually has quite a few benefits. Nothing to do with weight mind. The battery is protected from extremes of weather it's dry and kept at cabin temperatures.

            So the upshot of this is they last and last and last. I got EIGHT years from one - thats pretty average for an Xpic. Incidentally Citroen specify a sealed gel type so that if you turn it over it doesn't drip sulphuric acid over you. Nice touch!

      2. RAMChYLD
        Boffin

        Re: Could someone explain to me...

        > But is also helps keep the battery dry, there is often a lot of moisture flying around the engine bay

        > as its fairly open to the elements.

        And the point of keeping the battery dry? Since I had to regularly add battery water to the one in my car. Before it died and I had it swapped out for a maintenance-free one.

    6. Kernel

      Re: Could someone explain to me...

      The wire doesn't necessarily have to be thicker - the same overall diameter of high strand count cable could achieve the same lowering of resistance as a thicker wire with fewer strands.

      It's a 1/R(total) = 1/R1+1/R2+ ......... +1/Rn thing.

  3. paulf
    Joke

    Indicators

    I saw this recall and I wondered if it was to rectify a problem with broken indicators on all the BMWs I see on the roads....

    1. Phil O'Sophical Silver badge
      Thumb Up

      Re: Indicators

      I had the same thought, but no BMW driver would ever have noticed that the indicators weren't working.

      1. Anonymous Coward
        Anonymous Coward

        Re: Indicators

        Little know fault that if any attempt is made to use the indicators on a BMW it will immediately explode into a million bits.

        Whilst this fault has been present in all BMW models since 2001 there have been no reported incidents of any explosions to date.

        Bulletin ends.

    2. My Alter Ego

      Re: Indicators

      When I first got my Z4, I used to tell people that "I gave up trying to not use the indicators", but it was normally met with a blank look.

      Then again, my last 2 seater convertible was a Westfield and when you're driving 425kg of fibreglass & box metal, you damn well make sure that people know what your intentions are.

      1. Anonymous Coward
        Anonymous Coward

        Re: Indicators

        Surely a Westfield is the exact opposite of a Victorian child. They used to be seen but not heard whereas your Lotus 7isn't usually seen (first) but heard.

        Certainly the one on the A12 this morning was. I thought I can hear something rorty but can't see anything there! Then looking closer in the RV mirror there it was all low and whoosh...past me in a swirl of exhaust. Glorious!

  4. fifi
    Flame

    "The glitch has been known to prevent the vehicle starting."

    Yes.. I think turning a car into a raging inferno might well prevent it from starting...

  5. Whitter
    IT Angle

    What is it with the car stories?

    While I normally dislike the multiple domains for El Reg (multiple logins et al.), can we get a regcarstuff.com domain that I can just block? It would help if the content therein never got anywhere near the front page. In fact, perhaps some form of seperate car website might be the thing: who'd have thought?

    1. Rob Beard
      FAIL

      Re: What is it with the car stories?

      Erm... didn't you see the clue in the article title?

      "BMW recalls 1.3m motors over fire risk". They're hardly talking about laptops or cheese graters are they!

      How about blocking stupid users from the internet? Nah, it'll never catch on.

      Rob

  6. messele
    FAIL

    Perfect weight distribution?

    That's a bit of a joke. No car has perfect weight distribution, except when it's motionless, driverless and has a certain fuel load in it.

    Even F1 cars have a weight bias that is different on every circuit they race on - there is no such thing as 'perfect' weight distribution and it's never 50/50.

    Pretentious twaddle.

  7. robert_raw

    You have to applaud companies like this who risk damaging their brand to fix a fault.

    I would be more inclined to buy one than if they denied a problem

    1. Anonymous Coward
      Anonymous Coward

      Then you don't want a BMW

      BMW has had issues with their X35i high pressure fuel pumps since 2006 and they have not been able to fix them yet. New cars rolling off the assembly line still malfunction. Cars stall, refuse to start, loose all power, any time or place under any condition including at highway speeds. BMW's solution is to replace fuel pumps every few thousand miles and let owners take a chance on an accident - as some have experienced.

      The battery in the boot is for better weight distribution which BMW uses for marketing purposes. The longer the battery cable the higher the resistance so you do need to up the cable diameter to prevent a drop in power to the starter up front.

  8. ducatis'r us
    FAIL

    reliable BMWs (sic)

    and don't get me started on the swirl flaps ...............................

    1. squizzar
      IT Angle

      Re: reliable BMWs (sic)

      As I read from someone on a forum somewhere: "It's the ultimate driving machine, not the ultimate reliability machine". On my old 318is the battery is at the front, but I think the 6 cylinder ones had it at the back - countering the extra weight of those two cylinders as I understand it. My girlfriends significantly newer one has no battery to be seen - apparently it will never need replacing... we'll see. It's had the swirl flaps removed though.

      For a 20 year old car, my E36 is still one of the best things I've driven and just a really nice car to be in. Much more fun to drive than my much newer and significantly faster A4 - it just doesn't have as much feel as the BMW.

      Just for reference: My indicators work, and the mirrors and windows do a perfectly adequate job of allowing me to look before I change lanes. As a cyclist and motorcyclist I'm quite aware of the problem of people who can't be bothered to look where they are going, or so much as flick a switch to let other people see their intentions. It's not BMW driving c**ts that are the problem, or Audi driving c**ts that are the problem, it's just c**ts that are the problem.

      1. messele
        WTF?

        Re: reliable BMWs (sic)

        It's just curious how all those c*nts seem to want to drive BMWs or Audis. Come to think of it the Mercedes driver who thought it was clever to drive right down the middle of two lanes on a duel carriageway in front of me today qualifies too.

        To quote a friend's ex "See that badge on the bonnet? The blue propellor? That qualifies me to drive how the f*ck I want.

        Oh, like that is it.

        1. Anonymous Coward
          Anonymous Coward

          Re: reliable BMWs (sic)

          To quote a friend's ex "See that badge on the bonnet? The blue propellor? That qualifies me to drive how the f*ck I want.

          Your mate is a moron. Unfortunately he's part of a growing community of morons in this country.

  9. Anonymous Coward
    Anonymous Coward

    BMW is anything but the ultimate driving machine

    Don't get me wrong newer BMW's are decent driving cars they are far from the ultimate driving machine. As documented by all auto industry sources BMW has average to unacceptable reliability. Claiming they are more advanced and thus less reliable because of this is absurd and incorrect. Reliability has nothing to do with the driving abilities of the vehicle or how advanced it is. BMW has failed miserably on QC and reliability and is sliding South to meet up with VW. NHTSA just fined them $300 Million for failing to report safety defects in a timely manner.

    BTW, the battery in the boot is a good 25 kilos where it helps handling.

  10. Matt Bryant Silver badge
    Mushroom

    So.....

    ....any of those thousands of "Buy My Wares" repmobiles clogging up the middle lane each morning have a chance of turning into a "Burning My WHOOOOMPH"! Suddenly, traffic jams have become more interesting.

  11. Anonymous Coward
    Anonymous Coward

    Have fire extinguisher - will travel

    Keep your insurance paid up.

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