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06-01-2014, 12:02 AM | #23 |
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ezmaass:
link read content little:http://www.greencarcongress.com/2008...has-alrea.html and my mistake its 8 times not 10 times compared to conventional starter it was tested that using ASS lowers fuel consumption by 11% in city compared to not using it. you know i heard and read of quite a few malfunctions on BMWs, but it was very rare too find starter problems. |
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06-01-2014, 09:03 PM | #24 | |
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And again, that's the STARTER. While the starter is the component responsible for starting the engine, and it's obviously the control unit behind this technology, where's the study detailing the "toll" on the engine? As I said in my last post, each time you take a bunch of moving parts and stop them, only to start them in motion again, friction has a way of wreaking havoc - hence wear and tear. Even if the starter became a non-issue (and perhaps it is given the attention to it's longevity for this technology), what about the rest of the engine and its conventional parts that get stressed when spun-up, including belts, pumps, etc? The article also seemed to insinuate that there was a savings of only "up to 5%" when tested in the New European Driving Cycle. And we all know that "up to" usually means something considerably less in the real world. So, let's say it's more like 3% on average. And now let's say that you spend $2,500/year in fuel. So, saving 3% in economy would mean a savings of $75/year. Not bad. After 5 years you've saved $375. Sounds nice so far. But again, the question is... have you taxed the engine and/or accelerated repairs by more than $375 worth after 5 years of this constant starting/stopping? I don't know the answer. I think time will tell. It's innovative, and I appreciate BMW thinking of our economy and CO2 emission... but it still feels a bit gimmicky to me at the moment. I'll need to see how it holds up over time and what's learned about the stress it places on the engine. I suspect that if you're leasing a new car for 3 years, this is a non-issue. It'll be gone well before you're likely to have any problems... probably more of a concern for owner #2 or the guy buying with the intent to hold onto the car for 5+ years.
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06-02-2014, 02:55 AM | #25 |
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Just to add to the discussion...
ASS has been prevalent in Europe/UK for many years now; the technology is about 10 years old. One would expect that if ASS had any major/serious issues related to component wear; it would have been well known, documented and in the media circles by now. Not advocating for or against it; but I think the component wear issue is not really a problem. I have not yet heard of a single complaint about ASS failure in the UK. (not saying there isn't, just that it is not that big a problem). Perhaps fuel saving is not such a big issue in the US, due to the cheaper (comparative) price, but in UK; any saving is huge. UK fuel prices are about £1.40/ litre (it was £1.50 just 6 months back); so any savings (howsoever small) is welcome. Having said that, I have coded mine to be permanent off all the time - I just do not like the concept; and nothing to do with component wear or fuel saving.
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06-02-2014, 09:17 PM | #26 |
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So, for the hell of it, I read a bit more into the technology. One interesting article I came across explained the wear on the battery as one of the biggest detractors, which also impacts the overall effectiveness of the system over time (in fact, over just 2 weeks from "new").
Because these cars need to continue to run major electrical systems (air conditioner, radio, wipers, lights, etc) when at a light with the engine shut off, they no longer rely upon alternator-driven engine power... but rather the battery. AGM batteries, the kind used in our cars, apparently do very poorly over time with heavy load - the kind caused by excessive starts and running heavy loads on battery power. One study (from Pacific Crest) showed that the effectiveness, when factoring in the battery wear, reduced the amount of benefit of the auto start/stop system in as little as two weeks of use and by as much as a 50% reduction in benefit. I don't claim to understand all of the math (nor did I try very hard to follow it all), but that's a pretty eye-popping claim. The article I read, which referenced the Pacific Crest study, seems to assume that these manufacturers will, despite knowing AGM batteries deteriorate in this fashion (and thereby reduce the benefit of these systems dramatically), continue to use AGM batteries due to their much lower cost than more suitable/advanced ultra-capacitor batteries. So it would be curious to know the average longevity stats for an F10 battery, for instance, among those who use ASS often versus those who turn it off. And is the battery, for instance, one of those parts that BMW outlines in the manual that may experience excessive wear as a result of ASS use?
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06-03-2014, 02:55 AM | #27 | |
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As I had written before, ASS has been around in Europe/UK for many years; and we have not heard any horror stories.
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06-03-2014, 02:51 PM | #28 | |
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This is a $500.00 repair that is paid for in about 12 months of driving if you drive 20,000 city kms a year and save 11% in the city and fuel is $1.50/liter. It might take longer if you drive more on the highway, of course the starter will last longer. What it comes down to is who do you want to give your money to? If you shut ASS off, you'll burn more fuel and pay more the the Arab countries. If you use ASS, you'll burn 11% less fuel in the city and when you starter packs it in, you can pay BMW instead.
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06-03-2014, 05:30 PM | #29 | |
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I think your last statement is probably the heart of the matter.
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06-04-2014, 07:04 AM | #30 | |
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My BMW dealer told me the reason we need trickle chargers in the colder areas of Canada is that the battery manufacturers don't make a high enough capacity AGM in a package size that will fit in our cars. So I trickle my battery once very two weeks in the winter and I've yet to see a low battery warning. I use ASS to save fuel unless traffic conditions (creeping bumper to bumper) means that it will keep switching on off every few seconds. What can I say, even though my car was close to $80,000, I enjoy saving fuel. Driven moderately in the city, I consumer 12.5 l/100 km, which is about 2 L/100 km more than my wife's last car - a 2003 Honda Accord 4 Cyl. Now that is what I call having my cake and eating it too.
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06-04-2014, 05:23 PM | #31 | |
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"Gen1 AGM and enhanced flood batteries perform poorly, leaving future market share in doubt. The start-stop battery cranks the engine 10x more than a traditional battery, and the lead-acid chemistry is simply unsuited for this workload. Current AGM and EFBs degrade rapidly, with AGM batteries losing half of the charge acceptance within two weeks after first use (i.e., it loses half of its fuel-efficiency gains). They are not good at holding steady voltage during a stopping event (e.g., car stereos/windshield wipers may not work when the car engine turns off)." They acknowledge that ASS technology is made possible due to AGM batteries and their advantages over standard lead-acid, but clearly the test results show the batteries aren't holding up well under use with these systems. Half of the charge acceptance being lost within TWO WEEKS of initial use is scary, to be honest. The article regarding the study went on to contemplate whether ASS was really just useful in helping manufacturers post better emissions results for European countries, since those tests have no requirement that would expose the degradation - only the initial results. And if you're selling your product in a country that heavily taxes the consumer based upon emissions, it's obviously a competitive advantage... so is it really about fuel savings for the consumer? Quote: "Ultracapacitor prices need to decline by approximately 50% to gain significant Gen2 share. Overwhelmingly, OEMs are interested in satisfying the European legislation at the lowest cost. With few exceptions, cost is the first, second and only consideration. The poor performance of the AGM battery is something these OEMs are willing to live with as they assume consumers (and regulators) will not notice or care about the fuel-efficiency losses soon after purchase. Representatives from Ford, BMW and Porsche all dismissed ultracapacitors solely on cost, even while recognizing the greater performance. The good news for ultracapacitors is that a few OEMs are interested in offering consumers the better performance. But in order to gain real market share, the module price needs to fall significantly." I'm certainly not an expert - I've only done some high level reading. But I'm likely to remain skeptical until there's a much broader adoption, longer-term maintenance history, and more independent third-party tests. The fact that BMW felt obliged to point out additional/accelerated wear-and-tear (which they wouldn't otherwise do unless they thought non-disclosure would be a liability), and some of the information like the Pacific Crest study I quoted above, leaves me less than convinced for the moment.
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06-16-2014, 05:18 AM | #32 |
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I wonder why BMW does not put this disclaimer UK or Europe.
Is it mainly because the US has higher litigation risk and BMW are just covering themselves?
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06-16-2014, 10:08 AM | #33 | |
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The US is certainly more litigious than other places. But I think the fact remains that there was a disclosure to protect against a liability (e.g. a class action lawsuit - such as the one surrounding the N54). If there existed no such liability, there would be no disclosure. Therefore, we can only conclude that the auto start/stop system must, with some amount of evidence in BMW's possession, produce excessive wear-and-tear on the engine and/or other "components."
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06-16-2014, 11:37 AM | #34 | |
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I don't doubt your reading, but I wonder about the source. No doubt , Pacific Crest who is bullish on capacitor tech and pushing the stock to investors would be talking down AGM battery technology, but is their research accurate? Further to the above, I've located the "The Truth About Cars" article you are referring to: http://www.thetruthaboutcars.com/201...-stop-systems/ One of the quotes from TTAC (quoting Pacific Crest) as follows - relating to batteries in 2013: "The Gen2 battery not only will do start-stops, but also basic regenerative braking, start-stop during deceleration and electric boost during acceleration. The battery will, therefore, need to be able to handle more cranking events, and more charge. Also, the battery will need to operate a partial state of charge (i.e., normally hold 70% to 80% charge) in order to absorb energy from braking events." But, 2013 is already here and the batteries are already performing better (as I noted above). As I wrote above, Pacific is pushing a new technology company (Maxwell), so I'd like to see some independent performance data on current AGM batteries before adopting the Pacific piece as the gospel on the subject. Your comments quoting Pacific seem to relate to the pre Gen 2 batteries. As I wrote earlier, AGM batteries are known for their performance under deep discharge conditions in the marine environment. Bosch is a major manufacturer of these batteries for automotive use and tout their abilities as well. The proof is how the battery performs in real life. I don't see anything yet to dissuade me from using ASS. Will my battery wear out more quickly? Yes. Will my starter wear out more quickly - probably. Will I save fuel? the consensus seems to be around 11%. So, if I save fuel and spend that obey buying a battery and/or a starter, I'm happy to so so. I'd rather give my money to the auto maker than foreign oil suppliers. And the payback on using ASS might be shorter as the middle east falls apart and gas prices start climbing.
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06-16-2014, 11:57 AM | #35 | |
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06-16-2014, 12:52 PM | #36 | |
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06-16-2014, 05:27 PM | #37 |
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With the LCI being so new, I doubt there will be any significant changes to the MY15, the 16 and 17 will probably see a "end of life" boost in equipment.
As for ASS, I always switch it off, simply because I have on several occasions it has stopped the engine when I don't want it to. Like in traffic circles, something we have a lot of in Norway, it's a pain to have the engine stop and have to restart when you need to quickly need to squeeze into an opening. Last edited by Noggie; 06-16-2014 at 05:43 PM.. |
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