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Car Forum / BMW Cars / December 20071991 BMW 850i Electrical Problems
When I first start the car in the morning I have multiple failures in a number of electrical systems ( windows, sunroof, windshield wipers, interior lights, door locks). However, after about 30 minutes of driving, everything usually works. The windows work sporadically at first but eventually works fine. Everything is fine until the car sits for ~8 hours or longer. Any ideas on how I should approach solving this problem will be greatly appreciated. > When I first start the car in the morning I have multiple failures in a > number of electrical systems ( windows, sunroof, windshield wipers, interior [quoted text clipped - 3 lines] > ideas on how I should approach solving this problem will be greatly > appreciated. I had a similar problem when I changed my stereo - I must have incorrectly wired something...dunno. But after I had the stereo professionally replaced the problems disappeared (power door locks randomly locked, power windows sometimes refused to work, trunk light not lighting up...). > > When I first start the car in the morning I have multiple failures in a > > number of electrical systems ( windows, sunroof, windshield wipers, [quoted text clipped - 5 lines] > > ideas on how I should approach solving this problem will be greatly > > appreciated. Your battery is probably the problem. It's not recharging properly. The reason why the car runs OK after 30 minutes of driving is because the alternator is supplying the current and is partially recharging the battery - the voltage increase is enough to make things run again. But it does not seem your battery is recharging enough to prevent problems at startup - there is a slight drain on the battery even when you are not running it (e.g. alarm system). Your car either has a bad battery or the wrong (non-OEM) battery. Check this out before you go after expensive electriconic parts or service. My advice is to use the proper BMW battery and avoid non-OEM batteries especially if they are "maintenance-free" unless you really know what you are doing. The new battery must be matched to the charging system. Don't just take the word of the battery vendor for granted. You need to match the specs. Read the posts under the thread titled "E39 540i symptoms". I already explained this common problem there extensively. http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&threadm=o9g1qvocj1bit7fgv 4uid13hgmkk9898b5%404ax.com&prev=/groups%3Fdq%3D%26num%3D25%26hl%3Den%26lr%3D%26 ie%3DUTF-8%26group%3Dalt.autos.bmw%26start%3D25 Good luck! > I had a similar problem when I changed my stereo - I must have incorrectly > wired something...dunno. But after I had the stereo professionally replaced > the problems disappeared (power door locks randomly locked, power windows > sometimes refused to work, trunk light not lighting up...). When you wire in additional electronic hardware or replace something with another electronic gadget that draws more power you may prevent the battery from properly recharging because the charging system no longer has any reserve to sufficiently recharge the battery. While it may have been a wiring problem in your case you should also note that to install electronics properly you should calculate what any change in power requirements may be and take proper measures before you install. Once the battery no longer carries enough charge its voltage will drop and then problems with a multitude of electrical components can occur. If you leave the car in this "brown-out" situation long enough you may do permanent damage to some of the gadgets. Michael > Read the posts under the thread titled "E39 540i symptoms". I already > explained this common problem there extensively. It's so 'common' no-one on the E39 forum has heard of it. Because it's nonsense. No-one in their right mind would fit a maintence free battery to an E39 - even if you could find one to fit, which I doubt.  Signature*Lottery: A tax on people who are bad at math. Dave Plowman dave.sound@argonet.co.uk London SW 12 RIP Acorn > > Read the posts under the thread titled "E39 540i symptoms". I already > > explained this common problem there extensively. [quoted text clipped - 4 lines] > No-one in their right mind would fit a maintence free battery to an E39 - > even if you could find one to fit, which I doubt. After-market batteries are often marketed as easy drop-in replacements and people are tempted to just take a naive approach. Mantenance-free auto batteries have been sold here for many years in this manner. Many people who buy BMWs like the E39 are not mechanics or electricians. In situations when the original OEM battery has died the car is often about 3-4 years or or older and chances are high the car was recently resold off-lease to a second-hand buyer. Second-hand buyers are often not used to the expensive maintenance regimen of BMWs like the E39. Some of them are also just kids who are lured to buying a "hot car" despite high insurance premiums. They have limited budgets and are tempted to believe the often broad claims of battery advertisements. There are many possible reasons why people try maintenance-free batteries on BMWs like the E39. Michael > After-market batteries are often marketed as easy drop-in replacements > and people are tempted to just take a naive approach. Mantenance-free > auto batteries have been sold here for many years in this manner. Maintenance free batteries have a gel electrolyte. And need special charging arrangements. If anyone sold you one of these for a car, find a new supplier, as they're *not* suitable. What you probably mean is low maintenance types which condense the vapours which are emitted from the acid back into the battery, with little or no loss. These require pretty well the same charging arrangements as the older type where you had to check the electrolyte level regularly - certainly all reasonably recent charging systems will be ok. They might well be advertised as maintenance free, but this isn't correct. They should still have the electrolyte level checked once in a while. Some makers did sort of 'seal' these batteries since they'd last a year or so with no attention, but most these days have normal removable plugs. Signature*i souport publik edekashun. Dave Plowman dave.sound@argonet.co.uk London SW 12 RIP Acorn >> After-market batteries are often marketed as easy drop-in replacements >> and people are tempted to just take a naive approach. Mantenance-free [quoted text clipped - 14 lines] >makers did sort of 'seal' these batteries since they'd last a year or so >with no attention, but most these days have normal removable plugs. I don't know about special charging arrangements Dave as I used this type on my boat - deep cycling (long periods of discharge followed by long periods of charge. There was only standard 90A 12V alternators fitted with built in regulators - Ok there were 2 (one on each engine) and there were 4 batteries! The only thing that evaporates from a lead-acid battery is the water (distilled) content. Gas can sometimes escape when charging heavily but as this is usually for a short period there isn't much alarm. Problems can occur when using something like a 200A charger on an 85Amp/Hr car battery in an enclosed space without it being vented (cell caps removed or tilted to stop the bubbles splashing everywhere). This will certainly KILL a good battery if done too often. Hugh Intelligence is not knowing the answer but knowing where and how to find it! Hugh Gundersen hsg@h-gee.co.uk hsg@bognor-bill.co.uk http://www.bognor-bill.co.uk Bognor Regis, W.Sussex, England, UK ------------------------------------------------- Vyisder Asmeni Orsisarsis Asderisorsis. B.Cozderiz Vunarz PERORZ ------------------------------------------------- > Your battery is probably the problem. It's not recharging properly. > [quoted text clipped - 19 lines] > > Michael Mike, Thanks for all this previous info on batteries. I, for one, did not know the difference in requirements between wet-cell and gel-type batteries.. Frank I HAVE A VEHICLE THAT IS DOING THE SAME EXACT THING. WERE YOU ABLE TO FIX THIS PROBLEM OR HAS ANY ONE ELSE. HAD THIS PROBLEM. (IT IS NOT A BATTERY PROBLEM) >When I first start the car in the morning I have multiple failures in a >number of electrical systems ( windows, sunroof, windshield wipers, interior [quoted text clipped - 3 lines] >ideas on how I should approach solving this problem will be greatly >appreciated. |
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