FlamingGoatBalls Posted June 27, 2005 Report Share Posted June 27, 2005 I have been told that a high output alternator will not put out very much voltae at idle but this seems a bit low. Am I looking at a new alternator? I havent seen it above 13.2. even on the highway but at idle it quickly drops way down. If its bad where is the best place to get a delco? Link to comment Share on other sites More sharing options...
WarrenJ Posted June 27, 2005 Report Share Posted June 27, 2005 12.2 volts is about what you'd expect to measure with the battery on your garage floor when it is not being charged by an alternator or other source. Anything above that voltage indicates that it IS being charged. The question is whether it is being charged adequately. A range of about 13.1 to 13.8 is normal. Anything above 13.8 or so is likely cause for concern. You don't want to "cook" the battery with an excessive charge. That said, why are you concerned? Are you having difficulty starting for example? Lights dimming at idle? Or what? Regards, Warren There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
Ranger Posted June 27, 2005 Report Share Posted June 27, 2005 Interseting. Mine always runs low-mid 14's except when the A/C is on, then it drops to high 13's. Link to comment Share on other sites More sharing options...
navion Posted June 27, 2005 Report Share Posted June 27, 2005 FGB, If you are not having any starting or other issues, then I would suspect that the DIC voltage display is not very accurate. If you have access to a quality DVM such as a Fluke, Triplett or a Simpson, I would check them against your DIC. I would suspect that Ranger's DIC is reading high. If the car's system is actually charging in the low 14's, his battery life will be pretty short. Britt Britt Link to comment Share on other sites More sharing options...
WarrenJ Posted June 27, 2005 Report Share Posted June 27, 2005 Interseting. Mine always runs low-mid 14's except when the A/C is on, then it drops to high 13's. Low 14s on short trips around town wouldn't worry me. After all, your charging system is recovering from a brutal discharge after having just started the engine @ hundreds of amps. I should have been more specific: extended periods of charging voltage above 14 volts WOULD concern me, but you know your car better than I do. Let's also not forget that charging VOLTAGE is only a half assed way of measuring charging CURRENT intuitively. It's the current you want to be concerned about. And your conclusions regarding charging current that you derive from charging voltage assume the battery to be in good condition. NOT necessarilly so! You must measure the current to be certain. A good automotive electrical technician has the tools to properly evaluate your charging system. Of course, whether or not he has the acumen is another matter. How many times have we all heard the story about the tech who first changed the battery, then the alternator, then the regulator . . . . ? Back in the days when I was involved with charging systems on buses (1970s) , it was the rule to set the charging voltage on over-the-road coaches at 13.6 to 13.8 volts. Urban buses had their charging volts set at 13.9-14.0 volts. Regards, Warren EDIT: navion's fast typing post arrived while I was still hunting and pecking. Yep, I'd first double check your DIC with a known good instrument. Uh, maybe that didn't come out quite right. There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises Link to comment Share on other sites More sharing options...
adallak Posted June 27, 2005 Report Share Posted June 27, 2005 ....Ranger's DIC is reading high. Sounds like a compliment. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Matt Posted June 27, 2005 Report Share Posted June 27, 2005 A few weeks back I had a bad ground problem, being that they were left off by a mechanic who swaped an engine for me. I had voltages of 12.1 to 12.8, my PCM was getting very stupid with the low volts and the engine was doing all sorts of bad things. I then found the grounds were missing and after instaling some rather hefty grounds the volts came right up to around 13.5 but because of the strain of a poor groud system the alternator went bad. The charging amps were only up to 14 amps with a weekend battery. I put on a new alternator and it was week, very low volts and low amps. I then got a delco for more money and I now see 13.6 to 14.2 volts and I have seen it pump out up to 75 amps with test equipment we have at work. With the head lights on and AC I see an even 13.7 most of the time. During day time with AC on I see 14.00 volts. I checked my display against my fluke multi meter and they are with in 10ths of each other, It was nice to see that. I did not expect them to be that close. Matt / W2NIW Link to comment Share on other sites More sharing options...
JimD Posted June 28, 2005 Report Share Posted June 28, 2005 I have been told that a high output alternator will not put out very much voltae at idle but this seems a bit low. Am I looking at a new alternator? I havent seen it above 13.2. even on the highway but at idle it quickly drops way down. If its bad where is the best place to get a delco? You test your charging system and battery condition every time you start the engine. If the battery can spin the starter motor fast enough for the engine to fire up, your battery and alternator are doing what they were designed / intended to do. Voltmeters are great tools. But voltage does not tell the complete story. When it comes to splitting hairs on a voltage reading, I would want to know what a Fluke meter tells me as opposed to a DIC voltage reading. If it happens one day that you need a replacement alternator, go with a new or rebuilt Delco from a GM dealer parts counter. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
Ranger Posted June 28, 2005 Report Share Posted June 28, 2005 I would suspect that Ranger's DIC is reading high. If the car's system is actually charging in the low 14's, his battery life will be pretty short. Britt As well as I can recall my voltage reading has been consistant since I've had the car (May 2000). I think I replaced the battery in the 1st year I had it (I'd have to check to be sure). It's lasted 4 or 5 years so far like that. Link to comment Share on other sites More sharing options...
FlamingGoatBalls Posted June 29, 2005 Author Report Share Posted June 29, 2005 Im not having starting problems but my concerin is that the battery is only able to carge while the vehicle is moving down the road and also that my alternator may be failing. If it is I would like to know well in advance. I have everything ill need to run some tests at school fluke 88's and vat 40 etc...i just dont know how to se them. Link to comment Share on other sites More sharing options...
johnnydone Posted June 29, 2005 Report Share Posted June 29, 2005 my car just started the same problem at idle it drops to 11.8-10.8 when i start to drive it quickly builds up to 12.8 and then to 13.2 but no more i like u am starting to think the altenator is on its way out but not sure it used to be 12.8 at idle 13.2-13.7 when driving and 14.2 after a cold start Link to comment Share on other sites More sharing options...
FlamingGoatBalls Posted June 30, 2005 Author Report Share Posted June 30, 2005 Interesting...13.7 was exactly the voltage that I used too see while driving as well. Im not looking foreward to an alternator replacement at this point. But im thinking it is in the cards. Matt can you describe how you hooked up the fluke? Thnx KC8LWG Link to comment Share on other sites More sharing options...
Matt Posted June 30, 2005 Report Share Posted June 30, 2005 Hey Tyler Hows it going? I hope you get your ride taken care of. The fluke is nothing special. We have a few pieces of test equipment at work. I never even pay attention to the names on the things. One unit for testing batteries, it puts a specific load on them to watch the volts and amp load to see how they hold up. It has cooling fans on it and you can cary it around from shop to shop. The other unit hooks up to the back of the alternator and to the battery ground and it has a clamp that goes over the battery plus wire. It watches the engine cranking amp draw and it will show the alternator Amp output. I through the fluke on the battery before I grabed the other equipment just to see what the volts were, I had noticed that the reading on the dash was the same as on the fluke. That is no big deal, I'm sure it would have been the same with any multimeter. I can only do basic things, enough to find if there is alternator output and to check if my battery has any guts left in it. Your school must have some nice test equipment, at work they let us buy what we need to do the job but they do not buy super grade equipment for us. By the way, study for your general ticket and get on 40 meters. I have spoken to people in your area in the past with signals of 40 over at times. Take care / 73 Link to comment Share on other sites More sharing options...
johnnydone Posted June 30, 2005 Report Share Posted June 30, 2005 had my alternator checked out the rebuilders are saying it looks like it blew a rectifier hence low charging rate i started calling around and ran into a supplier to the parts and rebuilder trade he sold me a new unit not delco at their price which was $89 said they have no complaints from caddy owners at that price i had to give it a shot i have to install it but no core charge so i can have mine rebuilt if this one doesnt work to my satisfation 1 yr warranty or money back Link to comment Share on other sites More sharing options...
JoeM Posted June 30, 2005 Report Share Posted June 30, 2005 Once again... 12.6 volts is a fully charged battery, 12.4 is half charged. If you remove your battery from your car and you get a reading much below 12.6 there is something wrong. Link to comment Share on other sites More sharing options...
Regis Posted July 1, 2005 Report Share Posted July 1, 2005 FGB, How old is your battery? My old battery started doing the samething when it was dying. It did, however, make it to the 7 year mark. A new battery cured the problem for me. It's been 2 years now and no problems. I'd check that out before unloading for a new alternator. "Burns" rubber " I've never considered myself to be all that conservative, but it seems the more liberal some people get the more conservative I become. " Link to comment Share on other sites More sharing options...
johnnydone Posted July 1, 2005 Report Share Posted July 1, 2005 battery is 12.6 volts out of car alternator is charging but weak 11volts at idle 13.2 highway should be 12.8-13.2 at idle 13.7-14.2 highway thanks for your quick battery diagnostics after i get it in i will keep everyone posted on how my non delco new alternator is doing if this alternator doesnt work or doesnt last i will then agree with everyone that it has to be a delco most delcos right are rebuilt this is a new unit i also talked to the delco authorized dealer here delco is starting a new line of alternators as product for different cars becomes available they will have a lifetime warranty unfortunately my alternator does not qualify yet i was going to let them install it till i found out mine was not lifetime the total would have been $466 if im able to job here $89 sounds a lot better Link to comment Share on other sites More sharing options...
pos2nat Posted July 1, 2005 Report Share Posted July 1, 2005 My DIC shows volts climbing to 14.2 when I first start up, then it goes down to 13.2 when the car is warmed up. But if I put on my lights, a/c and wipers, volts drop to 12.9, sometimes 12.8 at a stop light. When I drive off it hovers between 13.0 and 13.1. Over 2,000 rpm it drop to 12.8 with accessories on, with no accessories on it drops to 13.0 when over 2,000 RPM. I replaced my alternator last year with a reman from NAPA. I think it's not charging at full output. I can exchange it but the labor involved is a #$%^%^&**. Link to comment Share on other sites More sharing options...
johnnydone Posted July 2, 2005 Report Share Posted July 2, 2005 installed new alternator not too bad of job now i get 14.5 at staRT UP 13.5-13.7 ON NORMAL DRIVING LOWEST I seen so far is 13.2 at idle all equipt on i guess i shall see how long this new $89 alternator will last its not a delco but i still have my old one to have rebuilt if needed the prices i get to rebuild mine is $125 if anyone else is trying to do this job here is acouple of tips remove right wheel and lower coverpanel loosen and reposition right radiator fan out of way buy a 15 and a 17mm racheting open end i wrenched mine with open end wrenches it was a long and tedious job these are the 2 bracket bolts on back of the alternator to start putting the rear bracket bolt back in i used sticky dualsided tape so that i could attach the bolt to my index finger to position it in the hole believe me there is no room dont forget to have cardboard ready to cover inside of radiator to save your hands Link to comment Share on other sites More sharing options...
bobnsue2 Posted July 2, 2005 Report Share Posted July 2, 2005 Hi, During troubleshooting a rough running problem, I saw the voltage was around 12.8 to 13.3 After a lot of testing parts replacing and swearing about the rough running, I wondered if the low voltage could be confusing the computer, So I had the system tested at an autoparts (Kragens). I thought the gut wasn't very competant so I talked to the guy I trust at NAPA. He couldn't come out to the car to test fully, so I took my battery and alternator to the counter. The battery (one year old) was fine and the alternator tested at 14.6 volts at 138 amps with no ripple. This is for a 140 amp alt. So they were perfect. What finally fixed the rough running was adding a better ground jumper from the engine to the body ground bolt. This also brought the volts up to 13.9 plus. Bob B Link to comment Share on other sites More sharing options...
johnnydone Posted July 2, 2005 Report Share Posted July 2, 2005 hi i did not have a rough running problem good suggestion though thanks so far my new $89 is running correctly no idle issues 13.2-13.4 14.5 startup 13.5-13.7 warm well we will see how long this no name new alt will last Link to comment Share on other sites More sharing options...
Matt Posted July 4, 2005 Report Share Posted July 4, 2005 I thought it was very interesting to see yet another rough idleing problem caused by a bad ground. I'm glad bobnsue2 got that one fixed. I went through that one too. But boy how a couple of those big wide ground straps fixed that problem was great.. My charging system has been great, I see 14.4 max when I start the car for first time in the morning, it drops to 14.0 with in 5 miniuts then down to 13.8 on ride to work. (Short ride) It holds 13.6 to 13.8 with AC on weather day or at night with the Headlights on. I'm also very happy with cooling syatem. We had a few 90+ days with very hi humidity and I was every ware with it, with AC on and in traffic and on the hiway and it ran from 200 to 213 or 215 I forget. The car is being kind to me for all the work I put in it. I'm very happy with it. I feel bad for being so mad at it when it was at its worst. Link to comment Share on other sites More sharing options...
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