charging problem

[cwater02]

i have a 1993 festiva 5 speed man i cant figure this out ive replace the battery 3 times and the alternator twice and by the way my alternator is a 100amp one prong chevy alt i check the volts on the alt when its running and its putting out 13.76 volts when i take one side of the battery cable off the car dies when the battery is fully charged i can drive it until the battery goes dead i cannot figure out y the alt wont keep the battery charged :?: very frustrating

[kzbill]

how many wires are on the festiva alternator? and are your grounds any good? I'd say check the diagrams and make sure the alternator works on the system. I know a lot of conversions are made with the chevy alt, cause they are cheap but that doesn't mean it will work by only hooking up one wire and no others. I don't have the diagram here right now so I can't say for sure.
Check out the diagrams and make sure everything is correctly wired.

[quaddawg]

NEVER NEVER NEVER NEVER NEVER take a battery cable off on a car that is running.. (modern car with an alternator)d That is something you used to be able to do with a generator or a mechanical voltage regulator, , but modern alternators are electronically (usually internally) regulated and without a voltage present (negative AND positive to battery) it will not work, there has to be a complete circuit. If you take one of the battery cables off an internally regulated alternator, it can produce over 600 volts, unregulated and can blow out ANY electrical device that is switched on at the time. headlights, ANY light, motors, sensors, relays, you name it. One of the FIRST things this ruins is the VOLTAGE REGULATOR, no matter where it is located.. internal, OR external.

I am guessing that your test has blown every regulator in every alternator you have tried it on, A GM10 or 12si alternator is internally regulated, and you will blow the diode trio almost as soon as you remove the battery cable, especially if you try to rev up the engine while doing so. I have personally seen a plain old GM alternator produce over 600 volts while running a test, on a bench, with no battery voltage (or load) to the internal regulator.

I am not sure what your charging problem is, but NEVER take a battery cable off a moderne running engine. I have seen entire electrical systems ruined.. I have seen headlights go poof, computers go poof.. Yeah, sometimes you can get away with it if EVERYTHING is turned off, but it proves nothing, and is unsafe and quite dangerous to your car.

Are the batteries and alternators you are swapping out new? I am quessing it is a connection/ground problem, but you probably have something else by now too.

One more thing, check the bulb in the alternator idiot light on the dash.. sounds silly, but some cars use that circuit as the "exciter" voltage to the regulator, and when they don't complete a circuit, like with a burned out bulb, the regulator isn't going to work. I have no idea if Festys work like that or not...


My father ran a starter and alternator shop for many years of my young adult life, and now, at 46, I can truly say we made a KILLING off of people that pulled a battery cable to "test" their alternator, it almost always kills a electronic regulator, and MANY MANY times has killed more, including ECU's... you can take this advice to a bank, I know we did.


If you don't believe me, just do a search..

Here, check this for an explanation

http://free-auto-repair-advice.blogspot.com/2007/11/testing-alternator-without-blowing-it.html

[kzbill]

Cool, what a way to diagnose a charging problem, by creating one.

[FestYboy]

^^^
Also, you can't run a car off the alternator by itself without somehow compleating the circuit (i.e. the battery). The battery acts as a giant buffer for current spikes (like when you remove the cable to test the alternator). And one last thing, you need a battery or some external power source to opperate an alternator, it won't make power by itself (it's not a generator).

PS: cwater02, please use punctuation so that others reading your post can see where your ideas begin and end.

[worfdog]

when i have changed my old jeeps over to the gm type internally regulated alternators, i have to rev the engines up to 1500 to 2000 rpms to make them start charging. after they cut in they will charge no matter what the rpms are.

[quaddawg]

when i have changed my old jeeps over to the gm type internally regulated alternators, i have to rev the engines up to 1500 to 2000 rpms to make them start charging. after they cut in they will charge no matter what the rpms are.

That is probably because you didn't provide an "exciter" circuit, through a BAT or ALT light. GM si like the 10 or 12si will not charge at lower rpms without the "exciter" circuit, but they do have a "cut in" at the higher RPM's to get them to override the exciter circuit.

That sounds exactly correct for that type of installation without an exciter circuit to get them to start charging.

[FB71]

^^^
Also, you can't run a car off the alternator by itself without somehow compleating the circuit (i.e. the battery). The battery acts as a giant buffer for current spikes (like when you remove the cable to test the alternator). And one last thing, you need a battery or some external power source to opperate an alternator, it won't make power by itself (it's not a generator).

PS: cwater02, please use punctuation so that others reading your post can see where your ideas begin and end.

huh? That's exactly what an alternator is, a generator! If everything is connected correctly, the can run on just the alt, but its's not recommended, due to the AC ripple and lack of surge suppression (as you described). The battery is not required to complete the circuit, since it's wired in parallel with the alternator.

sounds like someone has a UTI or Lincoln Tech education... :twisted: Sorry, I'm just bustin' your stones a bit...

[quaddawg]

^^^
Also, you can't run a car off the alternator by itself without somehow compleating the circuit (i.e. the battery). The battery acts as a giant buffer for current spikes (like when you remove the cable to test the alternator). And one last thing, you need a battery or some external power source to opperate an alternator, it won't make power by itself (it's not a generator).

PS: cwater02, please use punctuation so that others reading your post can see where your ideas begin and end.

huh? That's exactly what an alternator is, a generator! If everything is connected correctly, the can run on just the alt, but its's not recommended, due to the AC ripple and lack of surge suppression (as you described). The battery is not required to complete the circuit, since it's wired in parallel with the alternator.

sounds like someone has a UTI or Lincoln Tech education... :twisted: Sorry, I'm just bustin' your stones a bit...

A car WILL run on just an alternator, but it's MORE than not recommended, if you think I don't know what I am talking about, I could give you a little demonstration. I once had this argument with a "good ole boy" in a 67 camaro, that had a NEWER GM alternator, internally regulated. He thought I was full of crap. I laughed and told him to turn on his radio, and his headlights and anything else he could think of and rev that sucker up and take off the battery cable.. you should have seen the fireworks.. The headlights went POOF, the radio burned out, and it ruined his alternator (well, the internal regulator anyway) right there in the parking lot, in front of his buddies..

Folks, this is years of experience talking here, not internet chatter, or old wives tales, or Good Ole Boy advice. The battery isn't just some big buffer, or anything vague like that. This is pure electronics. The electronic regulator needs feedback voltage to tell what rate to charge. Without that regulation, a good ole 12si GM alternator can produce HUNDREDS of volts, not 20, not 40... HUNDREDS. Your electronics, not to mention it's own regulator cannot handle HUNDREDS of volts. Take that to the bank, or don't I don't really give a crap. Go out and take your battery cable off while you engine is running, and rev the crap out of it... do it all you like, just don't come here and post when you burn up your regulator, and ANYTHING else that was plugged in at the time.. including your ECU..

Sure, you can get away with it.....at an idle... maybe... sometimes.... but if you don't burn out at least ONE diode in your alternator, I would be highly surprised..

Don't you guys remember all the stories of... I replaced a battery, a regulator, an alternator, time and time again, until I finally found the problem....????!!!!!!????? uh... wonder why so many of these stories exist??


IN THE GOOD OLE DAYS OF MECHANICALLY REGULATED SYSTEMS>.. YES!!! you could do this... but those days are OVER. OVER OVER... Electronically regulated alternators will not regulate correctly without battery voltage present!!! They will also not charge correctly when the ALTERNATOR light is burnt out. FIRST THING TO CHECK


I am telling you. My father showed me YEARS ago, when I was just 30 years old, that you could take a GM 12si alternator, and connect it to his test machine, off the car, with a belt drive, and rev that sucker up, and produce 600 volts and more. I saw it many many times as he would try to show ignorant redneck customers that they blew everything in their car because they took the battery cable off to check the alternator, just like their daddy used to do.... yeah... USED TO DO..


So, beleive me or not.... I don't really care any more.

Some of you folks might want to take a short course in automotive electronics.......... you need it.

[worfdog]

i agree with you 100% quaddawg, i have also seen it happen on quiet a few occasions myself. once a battery cable came loose and blew out every thing on a friends car.

[cwater02]

i have one wire that connects to the alt (the white wire) the other 2 wires that are on the plug are taped off and has been that way for about 2yrs.all the sudden one day i was coming home from work and my tail lights went out.then 5 miles down the road my car starts cutting out,everything is going dim.stereo quits and eventually dies.so i trailered it home left it set for about 3mths. moral of story i went through some water and i think thats what caused my problems. so 4 days ago i pulled it in the garage to find the problem.i found the tail light problem it was the relay.it got wet and fried it.so hopefully that solved my problem i tested my alt while the car was running and it was putting out 14.7 "problem solved" (not) i went out last night tested it again to be on the safe side ,running and everything off it read 9.98 . so i checked all the fuses again even th fusibles under the hood i check the grounds all the ones i know of cant figure it out "any idears" glad i have 2 more stivas but i really like this one

[cwater02]

charging problem

i have one wire that connects to the alt (the white wire) the other 2 wires that are on the plug are taped off and has been that way for about 2yrs.all the sudden one day i was coming home from work and my tail lights went out.then 5 miles down the road my car starts cutting out,everything is going dim.stereo quits and eventually dies.so i trailered it home left it set for about 3mths. moral of story i went through some water and i think thats what caused my problems. so 4 days ago i pulled it in the garage to find the problem.i found the tail light problem it was the relay.it got wet and fried it.so hopefully that solved my problem i tested my alt while the car was running and it was putting out 14.7 "problem solved" (not) i went out last night tested it again to be on the safe side ,running and everything off it read 9.98 . so i checked all the fuses again even th fusibles under the hood i check the grounds all the ones i know of cant figure it out "any idears" glad i have 2 more stivas but i really like this one

[cwater02]

can u tell me where all the grounds are

[cwater02]

i was wanting to know if i get a small charger and permently attached it to the battery and plug it into my ciggarette lighter will it help my alt keep my battery charged at all times.

[quaddawg]

i was wanting to know if i get a small charger and permently attached it to the battery and plug it into my ciggarette lighter will it help my alt keep my battery charged at all times.

no, it doesn't work that way, you have to find your charging problem.

At this point, I am betting on it being the alternator, probably the internal regulator.