Re: 1992 Sentra SE electrical problem

Well I don't know, but here's a few thoughts

If it's Summer where you are, and the whole engine was hot right through, then I wouldn't be surprised if putting one's hand on the alternator, it was very hot

But cars with alternators, should recharge a flat but good battery very quickly, although a long slow is needed for a proper full charge. When you have time, recharge your battery overnight (assuming a common home type 2.5 to 6 amps maximum charger)

As 1992 your alternator is probably about 80 amps capacity (I drove old cars with 18 amp dc generators ! )

Perhaps your battery is dying and your alternator's working it's guts out trying to cope. I guess you've already checked battery leads, and the earthing strap (motor to chassis) are good connections.

If not, unscrew and sandpaper/wire wool them clean, then a tiny squirt of CRC/WD 40/ thin smear Vaseline-petroleum jelly whatever, bolt up again etc

Battery voltage when "hot off the charger/ or alternator, should be

13.2 volts

Sometimes older cars get slightly dudd connections and wiggling a wiring loom, or unplugging and re-plugging connectors can fix dodgy connections for a long while afterwards

Obviously you don't wanna car to konk out on you, last time you's just down the road in a parking lot, is no real worries, but next time it could be the middle of the night, some dark alleyway, and there you are in a miniskirt and highheels and Mr Serial Killer's out lookin' for ya !

Someone else with extra knowledge please post too, let's try to help this dude out, eh.

HTH

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Catherine Jemma.......(Keeper of The Gem of Amara) Outback Western Australia .... snipped-for-privacy@agn.net.au.knickers

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Catherine Jemma
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If said lady had her friends with her -- Mr. Samuel Colt, Mr. Smith & Mr. Wesson, or Mr. O.F. Mossberg & Sons (or just a good military surplus .303 Enfield) -- the serial killer(s) would not be any problem...except that "the authorities" in Australia won't let people defend themselves...but they DO protect vermin roos and crocs. Go figure.

But that's another topic.

If the REGULATOR (if it has one) is applying the alternator's output to the battery properly, then it sounds like the battery is defective...not holding a charge, one bad cell or more than one bad cell.

That's a basic test done at any auto shop (at least here in the USA)...seeing if a battery keeps a certain voltage under a load. If it doesn't hold x-number of volts for x-number of seconds under a known load, it's bad.

I suspect your battery.

When you have charging system problems, the three main components of the system ALL need to be checked: Alternator/generator, regulator and battery.

Good luck,

John D.

Reply to
John D.

` Greetings and Salutations... Thanks for the input folks! After struggling with the ride a bit longer, and, poking about with VOM and other tools, I have swapped out the alternator. So far, it has run for 20 minutes or so on the road with NO problems. Apparently the alternator, although pumping SOME voltage out, was not pushing enough voltage or current to both satisfy the electrical needs of the car, AND get the battery recharged. Once I put a more sensitive meter on the circuit, I saw the lower than normal voltages coming off the alternator, and, finally understood the root of the problem. With the new alternator, I am seeing higher voltages in the system, closer to what I would expect to see. We shall see what tomorrow brings, as we have quite a bit of running around to do and the Nissan is going to be the ride for it. One other thing that will be interesting will be to see how long the alternator lasts. It is NOT an OEM unit, but, got a fairly good review from the local parts guy I deal with (Ron's Imports on Cherry Street in Knoxville) I read here and there that aftermarket parts die more quickly. Since the alternator that got put on there three years ago was an OEM part, and it did not last that long, I look upon this as an experiment. Regards Dave Mundt

Reply to
Dave Mundt

You said earlier that the you thought the alternator was putting out

14 volts...so I didn't think it was the problem.

Yes, you'll need to keep an eye on the charging system for a while...

John D.

Reply to
John D.

That was the puzzling thing for me, too... but apparently it was heat related, as it pumped out the 14V when cold, but, as soon as it started to heat up, the voltage would drop off to low levels. Spent most of yesterday morning and afternoon running around town, and, all worked just fine, so, I am hoping that it is taken care of for a few more years. Thanks again for the help... Dave Mundt

Reply to
Dave Mundt

Okay...good luck,

JOhn D.

Reply to
John D.

I am not familiar with your car but I am sure there is a large guage wire running from the alternator to the battery. What is the condition of this cable? Does it have green oxidation forming on it? Does it sound crunchy when you wiggle it around? Let me explain why I ask you this.

I am a not an auto mechanic, but I am a mechanic on electric forklifts ( like the kind you see in home depot). I cannot tell you how many times I see main battery cables (on forklifts)which look OK be the cause of electrical problems. The funny thing is these cable test OK with an ohm meter. The minute you try to pump larger current thru them they fail dramatically. Im gonna tell you right now...if I showed one of these cables to any college grad who took some electrical engineering course they would swear up and down that the cable was fine because they tested it with an ohm meter and I will leave them with their jaw hanging down when I put that same cable in one of my trucks. Now my trucks work in the 400-800 ampere range but I suppose that this could be applied to the average car in principle. I know some cars get their dash power ect. directly off of the stud on the starter motor. If this is the case with your car you may want to check these cables. Also I see BAD batteries that can display 12 volts with a meter all the time. The current capacity is what get comprimised. A BAD battery that will not accept a charge will make the charging device work harder(alternator). Charge your battery and then start the car with the spark disabled and the meter connected. You should not have a dramatic voltage drop. If you do you may have a bad cell in your battery. I am no expert in automobiles but maybe, just maybe I could have offered some useful info.

DAN

Dave Mundt wrote:

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generatorlabs

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