Welcome to the Corvette Forums at the Corvette Action Center!

Help with charging system

sriat

Well-known member
Joined
Feb 12, 2006
Messages
82
Location
Kansas
Corvette
1984 Bright Red Coupe
Bought my Vette 2 years ago. It is an 84 with 47k

When I got it, the alternator (Regulator) was bad. It was charging up to 16-19 volts. So I replaced it.

Recently when I drive the vette, after driving around town it will not start. Let me explain. All the power accessories work. Cooling fan runs, Dash lights up, etc. Voltage shows 11. something volts. When I put a jump start to it or a battery charger, it starts right up. So I think it is not the starter. (Starter does not kick in, not even a click, the dash lights dim a bit)

When running down interstate, it shows 13.4 volts (Maximum)

So my question is, what do other owners of around this year vette show on their volt indicator? ( I may have a weak alternator)

When you go to start your vette after warm and the fans are running, what volt do you show (Without engine running)?

FYI I put a Optima Red top in 6 months ago, Should not be a battery.

Any input would be appreciated!
 

c4cruiser

Well-known member
Joined
Feb 22, 2002
Messages
971
Location
Lacey, WA USA
Corvette
87 Gold Z52 Coupe 02 EB Z51 Supercharged Coupe
Have a load test done on the battery. It sounds like it may be on its way out. A couple of years ago, there were problems with some Optima Red Tops. A friend of mine put a Red Top in his 90 ZR1 last year and it died within two months. He got it replaced and that one lasted 4 months. He went back to an AC Delco and it's still in the car working fine.

Another thing you should check is for good contact between the cable ends and the battery terminals. You could have corrosion at the ring in the ground cable where it contacts the battery terminal. The ring may also be not contacting fully.

13.4v at cruise is pretty low. I would expect 13.9 to 14.1 with or without headlamps on. With the ignition off, a good fully-charged battery should show 12 to 12.5v measured at the terminals. With the ignition on but the engine not running, I would expect anywhere from 11v to 12v.
 

Notorious

Well-known member
Joined
Oct 9, 2005
Messages
53
Location
Confederate States of America
Corvette
Highly modified '95 A4 coupe
It sounds as if you have a dead cell. Your battery should show at least a true 12.6 volts~ after it's been sitting awhile. If you've just shut it off, turn the lights on for about a minute to remove the surface charge. It should then show in the neighborhood of around 12.6 v. I've not seen or heard anything about the Optima that comes close to impressing me. Even after a hundred plus years and many efforts, nobody has come up with anything as reliable as the conventional lead-acid automotive type battery for that purpose. It's been refined but really little has changed. I consider the Optima to be just one more in a long line of gimmick batteries that eventually will fade into oblivion when folks realize that they are just pi**ing away their money.
 

douglas foster

Well-known member
Joined
Aug 18, 2005
Messages
226
Location
minnesota usa
Corvette
1984 C4 Gold coupe, Z51, 4+3 manual, BBS rims,
father & son

I also installed the Optima battery, and cut down the positive terminal on top so it wouldn't short out on support. I found out the hard way, that this will cause the battery to short out. this terminal is a two part system,I put a small screw in it and its worked ok since. But as above i should have bought a Delco, Optimas, i know now, are over rated for what you get. I going back to Delco.
vett4-12.jpg
 

sriat

Well-known member
Joined
Feb 12, 2006
Messages
82
Location
Kansas
Corvette
1984 Bright Red Coupe
Update on where I am at

May have left out key detail. I have replaced the factory radio with a pioneer head unit and 2 kenwood excellon (SP) amps. While I do not run the system hard, it does draw power. I disconnected this setup for trial. No incidents so far (However only driven once)

I did check the posts for corrosion. Nothing. I even cleaned just to absolutely make sure.

I put my volt meter on the battery when car was off. It reads 12. 17 volts. (after sitting for a day) This seems fine.

I also checked the voltage when the car is running. It reads about .5 volts higher than the dash. So I may be getting the correct charge level.

Which leads me to believe the battery is fine. (I have another if I have an issue to test with)

So I think when I run the radio, it is drawing more than the charging system can provide. I believe the alternator is 80 amps. (May be 89) So assuming that the radio is drawing 40 amps or so (At full play) Maybe more, this would then drain the battery. I am used to newer cars where they put out more amps due to increased use of CLA and such.

Anyone have thoughts about my theory?

Thanks for your input
 
Joined
Aug 30, 2002
Messages
1,533
Location
Colorado Springs, CO USA
Corvette
84 Z51 auto R.I.P. 89 black roadster SOLD
Your charging voltage sounds fine. Based on your symptoms I would get it up in the air and get down there at the starter terminals and check those out...as well as the ground wire going to the block on the driver's side.

I run a pretty beefy Pioneer amp with a pair of Rockford Fosgate subs...and I DO run it hard (going deaf from all the 80's head-banging I s'pose...), with a stock alternator and a Delco battery...no problems.

Also keep in mind..."new" (or "rebuilt") does not always mean good...

Bill
 

c4cruiser

Well-known member
Joined
Feb 22, 2002
Messages
971
Location
Lacey, WA USA
Corvette
87 Gold Z52 Coupe 02 EB Z51 Supercharged Coupe
Where are you getting power for the amps? One pic shows two wires that appear to be just wedged into the side terminals. Are these the power loeads for the amps? This may not allow full contact between the cable ends and the battery terminals.

The head unit should not be an power issue as most HU's do not take much more power than the factory unit. The amps do draw current but the power connections should be such that they get the amperage they need.

The 84 should have an 105 amp alternator, so unless the current draw from your audio system is high, it should not be a big problem. How the power and ground leads from the amps are connected may be a concern. Was the install done at a car audio shop?

Check all of the grounds, especially the battery cable ground. It should be clean and tight.

A reputable auto repair shop can test your electrical system including the battery and alternator. You may even have something as simple as a slipping belt. Check the tensioner to make sure it's not weakened to where the serp belt is slipping on the alternator. Replace the tensioner and belt if needed.
 

sriat

Well-known member
Joined
Feb 12, 2006
Messages
82
Location
Kansas
Corvette
1984 Bright Red Coupe
The picture is not mine... I have connected the audio (Amps) to the top posts so should not be an issue.
 

sriat

Well-known member
Joined
Feb 12, 2006
Messages
82
Location
Kansas
Corvette
1984 Bright Red Coupe
Fixed the problem

It was the starter. After spending some time on the forum, lots of people referred to similar problems as "Heat Soak" on the starter.

Like others, the symptoms were worse the warmer outside it got.

I have only driven a couple of days, and it has been cooler. However after replacing the starter, "Vette" has performed flawlessly.

I will update if things change. Thanks for all the reply's
 
Joined
Aug 30, 2002
Messages
1,533
Location
Colorado Springs, CO USA
Corvette
84 Z51 auto R.I.P. 89 black roadster SOLD
It was the starter. After spending some time on the forum, lots of people referred to similar problems as "Heat Soak" on the starter.

Like others, the symptoms were worse the warmer outside it got.

I have only driven a couple of days, and it has been cooler. However after replacing the starter, "Vette" has performed flawlessly.

I will update if things change. Thanks for all the reply's

Been there done that!

Glad to hear you "got-r-done"! :beer

Bill
 

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors

Dealers:

MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Parts/Accessories:

Vetteskins

Advertise with the Corvette Action Center!

Double Your Chances!

Partners

Top Bottom