what is acceptable voltage output of alternator

rayford · #1 12-27-2002, 12:31 PM

I have the notorious 5 warning lights coming on when I rev my car over 1000 rpms. and I have read several posts on here about exactly the same thing,, it seems that it comes down to a charging problem of some kind... I just went to a parts store where they checked my battery, and alternator,, he said the battery was fine.. the diode ripple was fine (what ever that is ) but the alternator is apparently charging too much... at one speed it is charging at 13.45 and at another speed it is 15.70.. he seemed to think that was too high... Does anyone know if this is really too high and if so what could be causing it? I know in older cars I used to work on,, the regulator was usually the reason but on these, I don't know and I doubt if a person can just buy a regulator as I suppose it is built into the alternator. So, if anyone has any suggestions it would be appreciated, I really don't want to spend 150.00 if the alternator isn't the problem.. Thanks , Vernon
P.S. it seems to me that the alternator feels very hot but maybe they do get hot in normal opperation.

benebob · #2 12-27-2002, 12:36 PM

DON'T DRIVE YOUR CAR! You'll fry your battery and maybe a few other things. Your volt regulator is bad. I doubt its seperate from the alternator but in some early subies it was. You'll pay the same to get that replaced as you would to get it rebuilt. If you don't want to shell out the cash to have it rebuilt check out www.car-part.com for a used one. I have a spare that I'd be willing to send ya until yours is done (just so long as you pay shipping to and from) but for that price you could probably pick up a working one from a yard.

rayford · #3 12-27-2002, 12:50 PM

benebob... thanks for the site.. I looked, there are two places here in Missouri that has them..... do you feel fairly confident that is what is making my warning lights act as they are.... I was rather surprised that the test showed too much voltage, and I know what you mean about blowing something out with too much voltage, that happened to me on an old Ford but none of the things blown were expensive on it.. Thanks Vernon.

mohrds · #4 12-27-2002, 01:18 PM

Quote:

Originally posted by rayford
I don't know and I doubt if a person can just buy a regulator as I suppose it is built into the alternator. So, if anyone has any suggestions it would be appreciated

The regulator alone is about $65.00 It is cross compatible with many other Mitsubishi cars. It is inside the alternator, so a replacement requires heavy duty soldering and disassembly.

Good Luck.

Doug

rayford · #5 12-27-2002, 01:25 PM

I just ordered a used alternator with a 6 month warrentee, from a place in St. Louis from the website benebob gave me,, it is going to be 68.xx dollars all included,,,,, I hope that cures the problem... but I am still open to any suggestions in case that doesn't fix the problem.. Thanks.
Vernon

kuoh · #6 12-27-2002, 01:40 PM

I just replaced my alternator with a rebuilt from OReilly's for around $140. The voltages, according to the built in voltmeter on my stereo, were around 11-13 with the old one and around 11-15 with the new one. At idle though, it can dip as low as 10 with the headlights, stereo, and heater blowing.

KuoH

rayford · #7 12-27-2002, 01:45 PM

the lowest this one ever got was 13.45 but I am still wondering if this could cause the warning lights to come on... I can see how low voltage might cause it... lol. with my luck it is probably somethng else doing it...

Beav · #8 12-27-2002, 02:03 PM

14.2 is optimum maximum, with a tenth or two either way being tolerable. Excess voltage will start popping light bulbs and if high enough, your electronics. Excess voltage will also boil the electrolyte in your battery and cause its premature demise.

Seeing how there's nothing else in the car that generates electricity it's a pretty safe bet the alternator is the cause. The dash lights coming on is a result of a bad diode in the alternator. It's also an indicator that the device used to determine that the ripple was good wasn't totally accurate.

The regulator is replaceable, but by the time it goes bad the rest of the goodies inside probably need attention also.

I'm glad to be out of the OReilly's area. I'd have to shoot myself if I had to continue doing biz with 'Third Time's a Charm Auto Parts'. It always seemed that the first part was wrong and the second one broken or otherwise defective.

rayford · #9 12-27-2002, 02:19 PM

Thanks Beav for answering on this,,I feel you have been around when it comes to cars and so I feel better about buying the other alternator even though it is used. what the heck, the rest of the car is used.. well. the gadget he used to check the alternator seemed kind of simple to be able to check all that stuff he just hooked it to the battery,, maybe they all work that way, I don't know.. and I kind of feel the same as you do about ORillies the only ones worse for getting it right the first time is AutoZone.. Ok,,, thanks again.. Vernon.

benebob · #10 12-27-2002, 03:52 PM

Yes. If I were a betting man, which I am I'd take nearly any positive odds that its your volt regulator. I forgot to tell you be sure to call these places and act like you never heard of them before and ask for the part. If they quote you higher than the website tell them about it. If they go lower. You just made out! Most of the stuff was put on when the cars were new so now they're more apt to deal with ya. You did good though. I paid $56 with shipping and a 60 day warranty. Besides, this will give ya plenty of time to get yours rebuilt. Figure about $120-150 for that! Good luck and again I don't suggest driving. If you must put on all your accesories to lower the volts going back to the battery!

Earthworm · #11 12-27-2002, 03:58 PM

When my voltage regulator went on my car the voltage stayed near 12.0-12.5. It just didn't charge (especially under a load).

kuoh · #12 12-27-2002, 04:48 PM

Well, maybe I should break out the real multimeter and see exactly what the voltages are. And I've also run into the first part was wrong syndrome.

KuoH

Quote:

Originally posted by Beav
I'm glad to be out of the OReilly's area. I'd have to shoot myself if I had to continue doing biz with 'Third Time's a Charm Auto Parts'. It always seemed that the first part was wrong and the second one broken or otherwise defective.

Landshark · #13 12-28-2002, 08:25 AM

i usually get around 14.2-14.4V with a few accessories, and it will dip below 12V with heater, headlights, rear defroster (really sucks up the juice!) and braking. my voltage gauge display blinks when it goes below 12V. cool!

oab_au · #14 12-28-2002, 03:55 PM

The max voltage from the reg should be 14.7v. If the reg goes out, there is a 16volt 'fail safe' zener protection to stop cooking the electronics.

If the voltage gets to 16v then the reg has gone. If it is over 14.7 but does not reach 16v then it could be the voltage sense wire,. plugged into the side of the alternator.
Harvey.

rayford · #15 12-30-2002, 03:55 PM

I got my replacement alternator today and put it on,, the cured the 5 warning light problem,, I took someones idea on here and put a volt/ohm meter on the battery to check the voltage,,, it was way high.. this is with the old one before I changed it out, it was running in excess of 17 volts...much more and I could have powered my house with it.......... and when I got that reading, I then went over to my LeBaron and it was like 14.25 , I did that to make sure my tester wasn't lying..... now with this other one reading in the 14's , it started raining so I didn't dilly dally long out there.. So far all the damage I can find is it blew my low beam head lights,, hope that is all, I already has some spares for that,,,, So thanks to all who helped me get this thing back to normal , for as long as it lasts until something else goes wrong.. Thanks again. Vernon