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Discussion Starter · #1 ·
I just finished a frame off resto on my 71 convertible. I replaced the voltage regulator and alternator with new ones. When I run the car for any legnth of time acid leaks from the battery, wherever it can get out from, and there goes the new paint and battery tray. Is there a way to tell if the battery is being OVERcharged and is this is why the acid keeps coming out? If I have an alternator with an internal voltage regulator do I still need the one that mounts on the radiator support? Could this be the problem?
Help! Thanks guys.
 

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Discussion Starter · #3 ·
I just discovered that I didn't have any ground running from the back of the alternator post to a ground on the car. Only have the red wire and the plug with the other 2 wires going into the back of the alternator, would not having a ground to the alternator make the battery overcharge? I took the alternator off and had it checked, it looks like it's putting out the correct voltage, so the alternator is fine.
 

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Discussion Starter · #4 ·
I forgot to mention earlier that I also read a post on the headlights dimmimg slightly when the car is at idle. Today I replaced the original stock voltage regulator with a Wells (part number VR715 ) voltage regulator. I did this to help with the dimming light problem, would this be linked to the battery overcharging problem or is that a different problem in itself. Will put the battery back in the car tomorrow so wish me luck, and if you've got any more ideas or suggestions for me please make a posting. Thanks! John
 

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Ragtop. Two words of warning.

If your battery is sealed (maintenance free), be careful. Overcharging such a battery may cause it to explode.

Apart from the acid you are troubled with,
overcharging an 'old' type of battery will produce an explosive gas. Do not smoke when handling it.

How did you wire an alternator with an internal AND an external regulator ? Could be there is no regulation at all anymore, thus overcharging the battery if by chance the field is supplied full current.

Rob
 

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Discussion Starter · #6 ·
Hey Rob,
The alternator does not have an internal voltage regulator, so I assume it's doing it's job from the external vr. The battery has caps that come off to check the levels inside, thats where I saw the acid dripping from, I guess like it's "boiling out". Any ideas if the missing ground was making it overcharge? What else could there be I could check?
 

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If you did not have a good ground connection, it would not charge anything. Do you perhaps have a reproduction Delco battery, I have been told that they are bad on leaking, but I am not certain in the way yours is doing.

Jim

A.C.E.S. 4996


Frame off red 71 Chevelle SS454 + .040 / 560hp Convertible with white stripes, top & interior loaded with factory options: TH400, cowl induction, power windows, locks, cruise, tilt, top, trunk, 12 bolt 373 posi, A/C, AM-FM 8 track, power drivers bucket seat, mirror map light, trunk, hood, glove box lights, on the wheel GM air pressure gauges, Delco Jac Pac 175 (under hood vacuum powered air compressor) with under dash Delco air pressure controller/regulator, complete with Jac Pac 175 air shocks.

http://chevelle.ogleonline.com/jim.htm

1952 Chevrolet 4 door Deluxe Sedan with a 216.5ci in line 6 with the last RAJO (RAcing JOe) Power Cylinder Head designed by grandfather in the 1940's. Joe designed, built & sold all over the world performance heads during the 20's, 30's & 40's starting with the model T Ford. Joe drove in the FIRST INDY 500 in 1911 as car # 8.

Watch for my SS454 Chevelle as a pace car at Indy in 2011 (100 years after Joe) IF THEY WILL LET ME !
 

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If you have the old alternator & regulator, try putting them back on the car & see if it makes a difference. The only way to boil out a battery is by too high a charging voltage, if your alternator is tested good, then process of elimination, the regulator.

Jim
 

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Discussion Starter · #10 ·
I just replaced the voltage regulator today before I went to work, so wish me luck, I'll give it another shot tonight when I get home. I don't know what else I can check. Alternator checks out fine. I checked out your site and nice 71! Mine is Mulsanne blue,white stripes,buckets,console,black top and interior,350/350/12 bolt posi 3.73:1. Just if I can figure out this battery thing.
 

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On my 71, I have four 12 point bolts on the top of the radiator support from left to right, but on my latch mechanism & horn brakckets, I have more traditional 6 point bolts, what do you have?

Jim

I remember a real sharp new 71 or 72 mulsanne blue Chevelle SS coupe in the town I grew up in when I cruised 30+ years ago, blue was my 2nd choice!
 

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Discussion Starter · #12 ·
On mine I also have a few 12 point bolts holding the hood latching assembly to the top of the radiator support also. I believe it's 2 or so bolts. I'm not sure of their purpose either. The other bolts are standard. Kinda strange huh?
 

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Discussion Starter · #14 ·
I'm not sure if I'm going or not yet. I'd like to, it looks like a blast. I was looking at the ACES website of some pics taken at Chevelleabration last year and there was a guy there who had alot of pics posted from several car shows. If you can find them there is a pic somebody took of my car at a car show in Union S.C. If you want to take a look at it go to the ACES site, then go to:
info and photos from 2002/chevelleabration results/james devennys photo album/union show and I'm on the third page of photos. I was messing around one day and found it there, I guess somebody else likes Chevelles as much as we do.
 

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How about the Pigeon Forge Tennessee rod run that is the middle of next month. Last year there was 25,000 people lined up along several miles of 6 lane business highway watching 100's of cars cruise from early in the morning to midnight. It was the BIGGEST cruise I had ever experienced. Every kind of car from 1920 thru present was there. My wife & I even saw a fella driving a 20' long boat up 8' on a car chassis driving it down the street.

Jim
 

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Discussion Starter · #16 ·
Can't go to that one, other commitments already. I would like to go to Chevelleabration this year though, I've got alot of local things going at the moment, who knows I might just roll up there in Tennessee. We'll see.
 

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Discussion Starter · #17 ·
Not sure about that one, other commitments already. That sounds like alot of fun too. Man, a boat huh? That had to be something to see. I just started showing my car locally last year, so I haven't ventured off too far yet, but it's about time too soon. Took me about 4 years to finish the car so I'm pretty protective of it so far. Just been going to the local shows and cruise ins, thats alot of fun in itself. I'm just easing into it.
 

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Ragtop.

The charging circuit contains 3 objects: battery, alternator and regulator. All of them should have a good ground. The alternator is grounded by the mounting, but only when the engine itself is grounded properly.

Battery. If by chance the battery is not as good as you think, it may boil even when the rest is in order. When the battery is fully charged. Remove the connections from the battery. Measure the voltage. Should be some 12.8 V. Connect 2 high beam bulbs (55W each) to the battery and measure the voltage on the posts again. If the voltage drops a lot below 12V suspect the battery. Do the same thing with 4 bulbs.

Alternator. Like John said, measure the voltage on the B+ . Maximum should be some 14.7 V If above 15 V something is wrong.

Regulator. I must see the drawings, don't know by head. In theory: it has 3 functions.
1) Close a switch when voltage is high enough to charge the battery. This is why your headlights may dim at idle. The switch is still open when idling.
2) A voltage controller keeping the output at 14.7 V max.
3) A current controller keeping the current within limits. Again in theory, this control could cause too high a current flow to the battery, even when the voltage is at 14.7 V. But : this can only happen when the battery will allow that flow (bad battery).

I hope John will chime in again. He is much better in describing test measurements on the wiring and he knows all the colors (I am rather color blind).

Hope this helps.

Rob
 

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John,
I had similar problems, been there/done that
do a search, and you'll find my posts, (electrical gremlins)
to give you a heads -up though,
my problem was finally traced to a bad diode in the alternator. :mad:
 

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Discussion Starter · #20 ·
Thanks for all your help and suggestions guys! I pretty much eliminated everything except the voltage regulator. As I read in many of the other posts, I replaced it with the Wells VR715 solid state voltage regulator. Looks like it took care of the battery overcharging problem AND the lights dimming slightly when the car is idling. You guys are the best, thanks again for all your help! Keep on turning those wrenches!
 
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