High Voltage
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Joined: Mar 2005
Posts: 97
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From: Nashville TN
High Voltage
The car: 1992 Corvette 383
So i'm driving around the vette and i see the battery light come on. I look at the needle and it's buried in the hash marks and the top of the guage on the high side. It wasn't like this the whole time, it just kind of spikes up there for a second.
My digital thing goes...
14.6, 14.8, 14.6, 15.5, 14.7, 15.9, 15.1, 16.5, 16.0, 15.5, etc.....
It's in the hashmarks when it hits the 16 range.
I figure something with the alt is ****ed. I take it to autozone to have them test it and they first test the battery and the machine says the battery is bad.
Because the battery was bad they didn't test the alt.
Now, is it spiking because the battery is bad? Or am i spiking and the battery is bad because the Alt is overcharging?
So i'm driving around the vette and i see the battery light come on. I look at the needle and it's buried in the hash marks and the top of the guage on the high side. It wasn't like this the whole time, it just kind of spikes up there for a second.
My digital thing goes...
14.6, 14.8, 14.6, 15.5, 14.7, 15.9, 15.1, 16.5, 16.0, 15.5, etc.....
It's in the hashmarks when it hits the 16 range.
I figure something with the alt is ****ed. I take it to autozone to have them test it and they first test the battery and the machine says the battery is bad.
Because the battery was bad they didn't test the alt.
Now, is it spiking because the battery is bad? Or am i spiking and the battery is bad because the Alt is overcharging?
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
[QUOTE=CaptainCaveMan]The car: 1992 Corvette 383
So i'm driving around the vette and i see the battery light come on. I look at the needle and it's buried in the hash marks and the top of the guage on the high side. It wasn't like this the whole time, it just kind of spikes up there for a second.
My digital thing goes...
14.6, 14.8, 14.6, 15.5, 14.7, 15.9, 15.1, 16.5, 16.0, 15.5, etc.....
It's in the hashmarks when it hits the 16 range.
I figure something with the alt is ****ed. I take it to autozone to have them test it and they first test the battery and the machine says the battery is bad.
Because the battery was bad they didn't test the alt.
Now, is it spiking because the battery is bad? Or am i spiking and the battery is bad because the Alt is overcharging?
I would bet on bad regulator in the alternator.
So i'm driving around the vette and i see the battery light come on. I look at the needle and it's buried in the hash marks and the top of the guage on the high side. It wasn't like this the whole time, it just kind of spikes up there for a second.
My digital thing goes...
14.6, 14.8, 14.6, 15.5, 14.7, 15.9, 15.1, 16.5, 16.0, 15.5, etc.....
It's in the hashmarks when it hits the 16 range.
I figure something with the alt is ****ed. I take it to autozone to have them test it and they first test the battery and the machine says the battery is bad.
Because the battery was bad they didn't test the alt.
Now, is it spiking because the battery is bad? Or am i spiking and the battery is bad because the Alt is overcharging?
I would bet on bad regulator in the alternator.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
What's the battery voltage with the ignotion on and the engine NOT running? If it's 11.5 volts or less, chances are the battery is either bad or it needs a charge.
I would go to a reputable auto repair facility and have the system checked. They will do a load test on the battery and check the alternator output and let you know where the problem lies.
If the battery is bad, get a good quality battery like an AC Delco "Professional" battery, a Sears DieHard Gold or Interstate battery. The Optima Red Top is also a good choice but you do need to modify the battery tray holddown to get it to stay in place. Also the positive top post is very close to the angled frame support bar so be careful there.
If the alternator is bad, stay away from the Bosch units or any cheapie remans. Specifiy an AC Delco or Nippondenso alternator as a replacement.
I would go to a reputable auto repair facility and have the system checked. They will do a load test on the battery and check the alternator output and let you know where the problem lies.
If the battery is bad, get a good quality battery like an AC Delco "Professional" battery, a Sears DieHard Gold or Interstate battery. The Optima Red Top is also a good choice but you do need to modify the battery tray holddown to get it to stay in place. Also the positive top post is very close to the angled frame support bar so be careful there.
If the alternator is bad, stay away from the Bosch units or any cheapie remans. Specifiy an AC Delco or Nippondenso alternator as a replacement.
Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Originally Posted by aminnich
I would bet on bad regulator in the alternator.
blown diodes in you voltage regulator. Diodes are used to clamp the high voltage output of alternator to 14.8V(or somehere close to this). Dead battery or not, your regulator should clamp the voltage.
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Joined: Mar 2005
Posts: 97
Likes: 0
From: Nashville TN
I'll have someone look at it monday, it has a yellow optimum battery in it right now.
One thing my car was doing (well before this) is the lights flicker non-stop. Not an on/off flicker but like a very faint flicker like it would if you had a big sound system turned up. My car does have a sound system in it, but it does it even when everything is turned off.
Would this be a sign of the alt taking a ****?
One thing my car was doing (well before this) is the lights flicker non-stop. Not an on/off flicker but like a very faint flicker like it would if you had a big sound system turned up. My car does have a sound system in it, but it does it even when everything is turned off.
Would this be a sign of the alt taking a ****?
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Originally Posted by CaptainCaveMan
I'll have someone look at it monday, it has a yellow optimum battery in it right now.
One thing my car was doing (well before this) is the lights flicker non-stop. Not an on/off flicker but like a very faint flicker like it would if you had a big sound system turned up. My car does have a sound system in it, but it does it even when everything is turned off.
Would this be a sign of the alt taking a ****?
One thing my car was doing (well before this) is the lights flicker non-stop. Not an on/off flicker but like a very faint flicker like it would if you had a big sound system turned up. My car does have a sound system in it, but it does it even when everything is turned off.
Would this be a sign of the alt taking a ****?
With good battery, good clean and tight cable connections and bew alternator there is fair chance the 'flickering' will go away as well.
Sned me PM to let me know how it all turns out.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Flickering lights are caused by a voltage regulator in the alternator oscillating and could also be the cause of your dash voltmeter jumping around all over the place. You can prove its the alternator by unplugging the connector on the alternator with the engine running and observing that the flickering stops. Parts store alternator checkers don't check for oscillating voltage regulators. You can replace the alternator or take it to an auto electrical repair shop and have the voltage regulator replaced.
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Melting Slicks
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Originally Posted by jfb
Flickering lights are caused by a voltage regulator in the alternator oscillating and could also be the cause of your dash voltmeter jumping around all over the place. You can prove its the alternator by unplugging the connector on the alternator with the engine running and observing that the flickering stops. Parts store alternator checkers don't check for oscillating voltage regulators. You can replace the alternator or take it to an auto electrical repair shop and have the voltage regulator replaced.
excellent point. The jumping around around of your voltage and flickering lights can be thought of like a household light dimmer. The higher the voltage, the more current flow- brighter lightsThe lower the voltage, less current flow- dimmer lights
