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Battery Life

diver110diver110 Posts: 67
edited March 2014 in BMW
I very recentlyl bought a 2000 540i (the car was placed in service in 10/99). It appears to have the orginal battery, making it almost four years old. There appears to be a coding to it. If a green dot appears in a window it is fine. A black dot means charge. A yellow dot means replace. Assumnig I am looking at the right thing, the window has a black dot. I gather BMW puts the battery in the back to keep it away from engine heat and give it longer life. Should I replace the battery? What kind of life do people generally get from their batteries? Thanks.


  • bretfrazbretfraz Posts: 2,021
    There's no sense in tempting fate here. Have a new one installed ASAP.

    4 yrs isn't bad for a battery but everyone's experience is different so there's no real accurate gauge of battery life.
  • kinleykinley Posts: 854
    94 Towncar, 106,000 original battery

     95 T Bird, 66,000 original battery
  • swschradswschrad Posts: 2,171
    there is apparently enough anti-theft in the radio, and enough computer interlock elsewhere, that just pulling a battery out, taking it to the store, bringing back a new one and installing it leads to nasty results... mostly the radio asks for a security code you don't have, I seem to remember some have claimed other issues, like starting trouble.

    this is one thing you should be able to avoid if you have the dealer change it out, they should be cognizant of the issues.

    but you should figure out what your security codes are on radios, etc. and write them down now, while you can. see the dealer if you can't find the instructions.


    although it appears I don't have similar issues in my detroilet iron at first research, I am going to whip up a standby voltage regardless before I hook up my trailer brake controller direct to the battery. this will consist of a 12v gel cell hooked through a lighter plug to keep the radio, etc. memories alive while I fool around with the post connectors.

    there are "radio save" kits of a lighter plug and a 9-volt battery clip in auto parts stores. but if you have a hood, trunk, or door light on while you are changing that battery out, the 9v job will be dead in seconds. your general 1.5 CP bulb draws something just over an amp, so I figure a 6 AH battery from one of my computer UPS systems will do just fine.
  • jc1973jc1973 Posts: 63
  • alcanalcan Posts: 2,550
    96 Riviera, 66,000 miles, original battery.
  • nippononlynippononly SF Bay AreaPosts: 12,726
    last year (owned since new) 6 years old, 115K miles, original battery.

    2014 Mini Cooper (stick shift of course), 2016 Camry hybrid, 2009 Outback Sport 5-spd (keeping the stick alive)

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,604
    Depends on the car, battery placement and what the car's accessories need, too. A big car with lots of accessories in a very hot or very cold climate might tax a battery a lot more than the "average" car. Also, cars like Saab that put the battery next to the turbo (duh!), well, every two years was more than enough. Mayby a GEL battery in the trunk could go 8 years.

    Case in point---my Benz battery is over 5 years old, works fine day in and day out, but when I took it up to snow country it could not crank beyond 30 seconds (in 10 second bursts). So for 95% of my use it was good but for that 5% is was useless.

    I think 4+ years is a good time to switch out the battery if you MUST have absolute reliability under all conditions.

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  • fleetwoodsimcafleetwoodsimca Posts: 1,518
    Glad you said that, Shifty! I was fixin' to say something to the effect that here in Colorado, I can't hardly keep batteries for "extended" lengths of time. I suspect it has to do with the temperature extremes, and other factors as well. What I hate is my own tendency to push my (battery) luck, and pay for it royally in hardship!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,604
    It's interesting to note that extreme HEAT also hurts battery life. I've read that battery life sayh in Phoenix would be less than say in San Francisco (unless of course they STEAL your battery in SF, but that's another thread.)

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  • cutehumorcutehumor Posts: 137
    my autozone battery lasted 4 yrs and 3 months and 47k miles. Here in Memphis, the summer temps get up to 95+ heat index of 110 F
  • swschradswschrad Posts: 2,171
    the arizona dealers take out and ship back the OEM batteries, and put in ones with good old filler caps, so the extra evaporation can be dealt with.

    I've got a couple phoenix-area transfers in the office, but have not asked them to raise their hoods yet to verify this... ;)
  • fleetwoodsimcafleetwoodsimca Posts: 1,518
    And it DO sound a little far fetched, even if Consumer Reports said it. »:o]
  • kinleykinley Posts: 854
    One is 9 years old and the other 8. When thirsty, give em a drink.
  • armtdmarmtdm Posts: 2,057
    For under $75 99% of the time it is not worth the hassle to leave it in and be stranded somewhere and have to buy one under duress. Just replace it every 4 or so years.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,604
    It's one of those items on a car that isn't worth "stretching". Unlike some components, a battery is so critical to a car's function that without one you are basically sitting in a huge flower box. (unless of course you drive a diesel, then you don't need a battery as long as you never shut the engine off).

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  • swschradswschrad Posts: 2,171
    somebody posted a few weeks ago that today's electronic regulators will die right now if the battery is disconnected. which could take the alternator down, depending on the type of failure.

    sure a far cry from chrysler's introduction of the alternator, in which they took the battery out of a test car, and drove it coast to coast to coast to show the alternator provided more power than anything before.
  • fleetwoodsimcafleetwoodsimca Posts: 1,518
    So just exactly how do all of us experts rate the batteries? Which brand or brands is/are best? Given the chance to buy the brand of your choice, what is it and why?
  • armtdmarmtdm Posts: 2,057
    The Optima gel batteries are the best, can be placed upside down if necessary but way overpriced and the waranty is no better then the top of the line of the same brand, non gel.

    For me an AC Delco maint free (no caps/plugs to check level etc) and if no Delco available for engine then the best top of the line (non gel) highest CCA one I can find that fits the case at Advance Auto or Auto Zone . Go for the warranty (by that I mean the replacement free part of the warranty) the prorated portion is worthless. So a 2 year replacement free 4 year prorated is better then a 1 year replacement free with 5 year prorated.
  • fleetwoodsimcafleetwoodsimca Posts: 1,518
    I too have had very good results with AC Delco batteries, and they seem to be available for most everything. I understand that Interstate may be pretty durable. Most anything made by Exide is a good, quality grade of battery as well.
  • cutehumorcutehumor Posts: 137
    It was a good price only 29.99 plus tax. It's the standard with 1 year free replacement. My car is 11 years old so i don't know if a 5 year battery is worth the investment. lol
    otoh, the battery is made by Johnson controls which also makes the interstate batteries. I was thinking that maybe it might be a good deal.
  • fleetwoodsimcafleetwoodsimca Posts: 1,518
    Are all the Walmart Everstart batteries made by Johnson Control? Thanks for this tip. I agree that this is a big plus for the Walmart line.
  • haspelbeinhaspelbein Posts: 227
    ...took the 7.5-year-old battery out of my E-Class. (Yes, take out the rear bench, disconnect the venting hose, give yourself a hernia...)

    Amazingly enough, Sears sells a replacement battery that matches the CCAs and dimensions of the OEM battery for $99. It also has a pro-rated warranty up to 7 years. It makes me wonder if they really expect it to last that long.

    My original battery surely did. It still started the car reliably, but the voltage would sometimes dip during starts, resetting the clock.

    Anyhow, the new battery worked out great, and resetting the radio anti-theft is something that most owners of German cars are used to.
  • swschradswschrad Posts: 2,171
    the lifetime they really expect the thing to have is around the non-pro-rated free replacement period. you should see something over a 5 to 10 percent failure rate shortly after that. most non-trash batteries should go 2 to 3 years in a car with a good charger and regulator that isn't crashing across obstacle courses.
  • fleetwoodsimcafleetwoodsimca Posts: 1,518
    I would agree, swschrad , to the degree that the manufacturers seem to be getting rather optimistic/deceptive with their longevity designations on automotive batteries. I think your running a bit to the pessimistic side to imply or state that a battery is only good for the non-prorated period.
  • swschradswschrad Posts: 2,171
    except the infant mortality for batteries dropped in shipment and the like. when that free period is over, they are starting to see claims. but the distribution is probably the (in)famous bell curve of statistics, and there should be few claims for an additional year or two, and then they start rolling in at increasing rates.

    my personal uninformed opinion, based on no particular access to industry data at all, is that any battery that doesn't last at least 3 years without abuse (bad alternator or regulator, off-road racing, jumping across the cornrow furrows, running it dry, etc.) is one that I will never buy again.
  • fleetwoodsimcafleetwoodsimca Posts: 1,518
    ...of that attitude. I have had a new car battery go out on me right after the 3rd year. On the other hand, I've run a few way past the end point set by the warranty. I hope to just once buy a battery before the death of its predecessor!
  • haspelbeinhaspelbein Posts: 227
    Now I should really read up on my warranty. So far, my batteries have lasted far longer than 3 years. (Not that the last three years in California have been very hard on them.)
    Both the ones in my truck and my convertible are slowly approaching their 7th year of service.
  • 528iben528iben Posts: 1
    Not sure where other people bought there batteries, but I just bought one for my 1998 528i from the dealer for $218.00. Checked Sears and other stores first but none carried the battery that’s in the car (840 volts). The largest I could find was 805 volts.

    See my post “528i Starting Problems”. The new battery, so far seems to have resolved my 6 month random no start problem which several BMW dealers could not and did not even thing of the battery. The battery was the original that came with the car.
  • andre1969andre1969 Posts: 23,040
    I've actually done that a few times with my Mopars...pull the battery out while the car's running, and then drive it. Don't ask me why, exactly, I did it...looking back I can't remember! I never tried it with my DeSoto though. That car uses a generator. Would it not make it without the battery?

    Were Chrysler alternators better than GM alternators, back in the day? I know that Mopar went to alternators before GM, but what about when GM finally switched to them?
  • swschradswschrad Posts: 2,171
    that's cold cranking amps, not volts, on the batteries. not even the hybrids use 800-volt stacks.

    a generator car would stop dead because you have to turn the armature (basically the same thing as an alternator rotor) within a magnetic field to generate electricity. both alternators and generators use a field coil to set up that magnetic field instead of pounds of permanent magnets; cheaper, lighter, smaller, and lasts longer.

    generator fields were always energized from the battery, thus, take the battery off, no magnetism, no voltage... nothing to commutate for spark coil primaries, so no spark... you walk.

    old-style alternators, like the original Motorola ones that Chrysler introduced, had a mechanical relay voltage regulator that allowed the battery to energize the fields through a resistor, or allowed the rotor's wye-coil to energize the fields through a diode module... with the higher output to the battery going through larger diodes. so the original Motorola alternators could indeed self-excite just enough at idle to keep operating once started.

    doesn't work that way today, the battery is at minimum a reference voltage for solid-state regulators that control output by adjusting the current in the field coil. my big Ford alternator even has a lead from the engine computer to cut alternator output if you whack the accelerator hard and the engine needs to shed some auxiliary power beyond the a/c compressor to try and deliver. you pull the battery cable on a modern charging system and you will get an ugly and dangerous spark along with hundreds of dollars of charging system damage.
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