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over-voltage from alternator?
What could cause an alternator to put out too high a voltage? I will be
doing some checking tonight, but what has me worried is the wipers are going too fast when the engine is a road speed but are normal at idle, and the lights are showing a noticable brightening from idle to say 3000 rpm. Kind of like an old generator car which couldn't charge at idle. Probably just worrying on my part, but this is my wife's car which I rarely drive, and I am always on the lookout for problems creeping up when I do drive it. 96 Hyundai Elantra, fairly recent battery. Would charge voltage over 14.5 be a good indication of a problem? Thanks, Brian Thanks, Brian |
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#2
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14.5 Volts is fine.
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#3
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"Brian" > writes in article > dated Wed, 19 Jan 2005 09:32:11 -0500:
>What could cause an alternator to put out too high a voltage? A bad regulator. I think most regulators are built into the alternators these days. >Probably just worrying on my part, but this is my wife's car which I rarely >drive, and I am always on the lookout for problems creeping up when I do >drive it. 96 Hyundai Elantra, fairly recent battery. Would charge voltage >over 14.5 be a good indication of a problem? If it's 13.5-14.5 it's nothing to worry about. Use a digital voltmeter and have an assistant rev the engine to normal driving RPMs. -- spud_demon -at- thundermaker.net The above may not (yet) represent the opinions of my employer. |
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Spud Demon wrote:
> "Brian" > writes in article > dated Wed, 19 Jan 2005 09:32:11 -0500: > >>What could cause an alternator to put out too high a voltage? > > > A bad regulator. I think most regulators are built into the alternators > these days. > > >>Probably just worrying on my part, but this is my wife's car which I rarely >>drive, and I am always on the lookout for problems creeping up when I do >>drive it. 96 Hyundai Elantra, fairly recent battery. Would charge voltage >>over 14.5 be a good indication of a problem? > > > If it's 13.5-14.5 it's nothing to worry about. Use a digital voltmeter and > have an assistant rev the engine to normal driving RPMs. > > -- spud_demon -at- thundermaker.net > The above may not (yet) represent the opinions of my employer. If it goes above 15 volts, however, you should get it fixed. Nothing will kill a battery faster than too high of a charge voltage. BTW, most voltage regulators have a temp dependent circuit. They will charge higher voltage in cold weather. A good manual should have a spec on voltage vs temp. In meantime, if it is a battery you can check fluid level, do so very frequently. Overcharging kills battery by boiling out electrolyte. If you do not have a voltmeter in car, you can buy nice ones that plug into cigarette lighter. |
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On Wed, 19 Jan 2005 15:16:46 +0000 (UTC), Spud Demon > wrote:
>"Brian" > writes in article > dated Wed, 19 Jan 2005 09:32:11 -0500: >>What could cause an alternator to put out too high a voltage? >A bad regulator. I think most regulators are built into the alternators >these days. If it's a bad regulator, the alternator can be taken to an autoelectric repair shop and repaired for a lot less than a replacement alternator, typically $50-90. If you can't find one in the yellow pages it's because rents in your city are too high and smaller business can't stay in business. |
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Whenever my alternator acts like that, I either have a loose or polished
up fan belt or a dirty main battery connection. With the bad belt, the battery is never fully charged so the alternator is trying to 'catch up' so I see a high reading on the volt gauge and the lights get brighter. When I have a bad connection, same deal except it seems to put out higher to jump the bad connection. Or the alternator's regulator could just be worn out. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Brian wrote: > > What could cause an alternator to put out too high a voltage? I will be > doing some checking tonight, but what has me worried is the wipers are going > too fast when the engine is a road speed but are normal at idle, and the > lights are showing a noticable brightening from idle to say 3000 rpm. Kind > of like an old generator car which couldn't charge at idle. > > Probably just worrying on my part, but this is my wife's car which I rarely > drive, and I am always on the lookout for problems creeping up when I do > drive it. 96 Hyundai Elantra, fairly recent battery. Would charge voltage > over 14.5 be a good indication of a problem? > > Thanks, Brian > > Thanks, Brian |
#7
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"TCS" > wrote in message ... > On Wed, 19 Jan 2005 15:16:46 +0000 (UTC), Spud Demon > > wrote: >>"Brian" > writes in article > dated Wed, 19 Jan 2005 >>09:32:11 -0500: >>>What could cause an alternator to put out too high a voltage? > >>A bad regulator. I think most regulators are built into the alternators >>these days. > > If it's a bad regulator, the alternator can be taken to an autoelectric > repair > shop and repaired for a lot less than a replacement alternator, typically > $50-90. If you can't find one in the yellow pages it's because rents in > your > city are too high and smaller business can't stay in business. Very good advice. I recommend getting a electric shop to fix your alternator as well. The good thing is they will fix what's wrong, not just replace everything and hope that they get it. They have the ability to diagnose and repair the alternator properly. Around here (Dallas, Texas) the local shop will fix any alternator for $45, replacing only what's gone bad. Also, the shop uses better components than those that are found in the rebuilt units of the auto stores. -Bruce |
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On Wed, 19 Jan 2005, Bruce Chang wrote:
> > If it's a bad regulator, the alternator can be taken to an > > autoelectric repair shop and repaired for a lot less than a > > replacement alternator, typically $50-90. If you can't find one in > > the yellow pages it's because rents in your city are too high and > > smaller business can't stay in business. > Very good advice. I recommend getting a electric shop to fix your > alternator as well. The good thing is they will fix what's wrong, not just > replace everything and hope that they get it. They have the ability to > diagnose and repair the alternator properly. They also have the ability to swear and curse at their would-be customers who bought Korean cars and are dumb/ignorant enough to expect to be able to fix them. |
#9
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Brian wrote:
> What could cause an alternator to put out too high a voltage? Several things pop to mind. -Failed voltage regulator -Short to ground in the field circuit (if its a regulate-on-the-ground-side design like most are) - short to ground in the alternator rotor itself. - broken wire to voltage regulator reference |
#10
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On Wed, 19 Jan 2005 12:16:08 -0500, Daniel J. Stern > wrote:
>On Wed, 19 Jan 2005, Bruce Chang wrote: >> > If it's a bad regulator, the alternator can be taken to an >> > autoelectric repair shop and repaired for a lot less than a >> > replacement alternator, typically $50-90. If you can't find one in >> > the yellow pages it's because rents in your city are too high and >> > smaller business can't stay in business. >> Very good advice. I recommend getting a electric shop to fix your >> alternator as well. The good thing is they will fix what's wrong, not just >> replace everything and hope that they get it. They have the ability to >> diagnose and repair the alternator properly. >They also have the ability to swear and curse at their would-be customers >who bought Korean cars and are dumb/ignorant enough to expect to be able >to fix them. Newsflash: there are no 100% domestic cars or 100% japanese cars. Your statement was nonsensical. |
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