Battery fried and more

-
Batesy

Batesy

Well-Known Member
Joined
Aug 7, 2013
Messages
85
Reaction score
1
Location
Fairfield, Ohio
Car: 75 Dart Swinger
Initial problem: Battery was hot, boiling, etc. after driving for an hour or so.
Initial fix: Changed out voltage regulator and ballast resistor. Checked battery while running and it was at about 14v and seemed ok.
Drove it the next day to work and the battery began overheating again. Took it to Sears (where I had bought the battery just 2 months ago). They gave me a new battery but told me that when they disconnected the voltage regulator the battery (while the car was running) was at 17-18v.
Tomorrow my friend and I are going to check grounds. There was one wire coming off the alternator that had a connector that was severely burnt looking. I should mention that, whether it has anything to do with it or not, right before this started happening my friend and I had bypassed the bulkhead connector. We are going to go back and look at our work. I don't think that it should be creating this problem somehow but I don't know for sure. Any thoughts on where to start or check would be greatly appreciated.
 
I'm sure it's a charging system problem as opposed to a battery problem

ARE you SURE your voltmeter is ACCURATE? I just ran into a cheap digi multimeter a friend "down the alley" has which is WAY off

Check your meter on your line voltage. It varies, but should be around 117--125V AC Measure a few flashlight batteries. Measure another one of your cars. With engine warm and battery "normalized" voltage should run right at 13.8--14.2

In fact, what, exactly and how, exactly, are you measuring this voltage? You no longer have a working ammeter, I assume? What modifications have been done to the wiring?

===========================================

Common problems:

1....Voltage regulator not grounded. VR MUST MUST be grounded. This means a SOLID ground path between battery neg. terminal and the VR mounting flange.

With engine running, warm, and (you hope) battery normal, make this test first with all accessories off, and again with heater, lights, etc on

Clip one probe of your meter to battery NEG terminal. Stab the other probe into the regulator mounting flange. Make sure to stab through paint, chrome, rust. With the meter set to read low DC volts, you hope for a very low reading, zero is perfect. Anything over .3V (three tenths of one volt) is too much, and it SHOULD be lower.

If any QUESTION, remove and clean the regulator flange, scrape around the bolt holes on the firewall, and re-mount using star lock washers. You can also add a jumper ground wire from the block to the firewall. On a V8 there are unused holes on the back of the driver side head. Look at the front of the pass. side head!!
=============================================

2....Voltage drop in the electrical harness. This is the supply voltage to the regulator which is also SENSING voltage. On a "stock" harness, the circuit path is...........

Battery.........starter relay stud.........fuse link........through the bulkhead.......through ammeter..........to ignition switch connector.......through the switch........back out the switch connector.........back out the bulkhead connector.........to underhood loads. This is "ignition run", the switched 12V which supplies ignition, regulator, etc

To check this, turn key on to "run" but engine off. Clip one lead of your meter to battery positive, the starter relay stud. Hook the other probe to either the blue alternator field wire, or to the "key" side of the ballast.

You are again looking for a very low voltage. Over .3V means you have problems. This voltage, whatever it reads, is ADDED to the regulator voltage.
===========================================

3.....Check CAREFULLY the VR connector, which is related to 2 above. Inspect the pins and connector for corrosion, and work it in/out several times to scrub it clean, and to "feel" for tightness.
===========================================

4..... A bad / defective VR.

===========================================

5.....Very rare but can / does happen, is some wiring fault which causes the field terminal of the regulator hooked to the green wire going to the VR to ground. This could be a bare wire in the harness, but more common is a BROKEN or damaged brush holder at the alternator. Pull it apart and inspect, or if you can "catch" it when overcharging, shut off the engine, and check for continuity...............

With the two field wires pulled off the alternator, there should be continuity between the two field connections. NEITHER field connection should show continuity to ground.
 
Had the same problem when I changed my regulator. I didn't have it grounded good enough and it boiled the battery from overcharging and even blew some of my lights. The regulator screws didn't fit tight to the sheet metal. I put in the next bigger sized screws and some star washers to fix the problem. I also went back to a points style regulator instead of the new electronic style which use the ground side of the circuit to complete the electrical path.
 
The old "points" type is no improvement. There might be LESS current in the ground path, but the thing is ANY (even old generator) regulators must be grounded, as that is part of the voltage sensing circuit.

On a V8 a simple way to add a better ground between engine and body is to buy a short "starter" cable (eye to eye ends). Bolt to the rear of the driver side head, "U" the slack down, and bolt to one of the master cylinder bolts.
 
could be a shorted diode in the alternator
wont show up on a voltage meter but will kill a battery

take the care to autozone and have them check your charging system.
 
trapster said:
could be a shorted diode in the alternator
wont show up on a voltage meter but will kill a battery

take the care to autozone and have them check your charging system.
Click to expand...

Nope sorry. Not this time
 
67Dart273 said:
The old "points" type is no improvement. There might be LESS current in the ground path, but the thing is ANY (even old generator) regulators must be grounded, as that is part of the voltage sensing circuit.
Click to expand...

I agree. The electronic reg's are more precise in controlling the output. I just put my old regulator back on because I knew it worked and the poor ground I had with the electronic one didn't. I could put a electronic one on now with a good ground and it would be ok. tmm
 
Had same problem it was the alternator. Got rid of the rebuilt POS and put an original from the JY on it and has been good for 2 years now. Some thing shorts in the alternator and the regulator no longer "regulates".
 
I never rely on a (rusty) sheet-metal screw to provide the ground. I know the factory did, but they were just concerned with moving cars off the showroom floor, not 40 yrs later.
 
I remember see my accelerator cable glowing red hot at the connection to the carburetor once when I forgot to ground the engine.

At the time I was wondering why my radio sounded funny.
 
Update: First of all, sincere thanks to everyone who responded.
Ok, so we thoroughly scrapped and cleaned all ground connections down to bare metal -Voltage regulator, alternator, etc.
When the car starts up the voltage meter would show the voltage climbing quickly up to 17-18v. Shut car off quickly.
We disconnected the field wires on the alternator and the battery would be steady at just over 12v. We discovered that this would also happen when you would hook up the positive field wire BUT NOT the negative field wire. When the neg field wire was disconnected, the battery would be stable around 12.3v.
To answer 67DART273: today we used a quality tester and the only wiring mods we have performed is bypassing the bulkhead by running a heavy gauge wire with appropriate sized fusible link from the alternator output stud directly to Bat (+) stud on starter relay.
So we are at a standstill right now.
 
Vreg controls the voltage it senses, which is not the battery voltage, but rather a point after the key switch (usually IGN1 wire). If there is a drop to that point, it will try to make that point the desired 14.3 V (rel. to its case), which could jam the alternator at full output, trying to make Vreg happy, which could be 18 V at the alt out stud. Use a multimeter and wiring diagram to measure the voltage (from BATT-) at these critical points. Excessive drops thru corroded firewall terminals are very common, and there are many, many posts on this so search if what I detailed is confusing.
 
Batesy said:
We disconnected the field wires on the alternator and the battery would be steady at just over 12v. We discovered that this would also happen when you would hook up the positive field wire BUT NOT the negative field wire. When the neg field wire was disconnected, the battery would be stable around 12.3v.
Click to expand...

Let us make this clear:

Are you saying that with only the blue field wire hooked up the voltage overcharges?

IF THIS is the case, you have a problem in the brush holder / insulator, or a short in the actual field winding in the rotor.

TO make sure:

Unhook both field wires, motor off. Check continuity from each alternator field terminal to ground. It should be infinite, that is "no" continuity

If there is continuity, the alternator has a problem
 
No, the charge was steady when the BLUE field wire was NOT connected. The green wire was still connected.
 
Batesy said:
No, the charge was steady when the BLUE field wire was NOT connected. The green wire was still connected.
Click to expand...

OK still not making clear. "Steady" doesn't tell me what you mean..................... The voltage "surface charge" on the battery may be fooling you

(Did you run the continuity checks?)

Try this:

1...With everything hooked up normal, confirm what it is doing voltage wise, running fast, so I'll assume "high" but post the battery running voltage

2...If the voltage is high, above 15V, pull the blue wire off and turn on the headlights, continue to run and post battery voltage for at least 1 minute. Battery voltage should drop to 12 .....something.

3...Then, Unhook the green and hook the blue back up, and continue to run long enough to see if the voltage climbs high again.
 
Alright, it turns out that it was in fact the alternator. There was an internal short to ground. Replaced and everything is a-ok.
 
trapster said:
could be a shorted diode in the alternator
wont show up on a voltage meter but will kill a battery

take the care to autozone and have them check your charging system.
Click to expand...


AGREE, run it down to your local parts store and have them hook up the tester and check the charging system. Usually free and it will tell you immediately if the alternator output is high.
 
trapster said:
sounds like it could have been a shorted Diode
Click to expand...

No this would have been a shorted brush. This is EXTREMELY important to understand because if you are unlucky enough to get the blue field wire (switched 12V) hooked to the shorted brush, you can burn up the harness

I've seen at least a couple of so called "rebuilts" come this way right out of the box. Part of the problem comes from garbage rebuilders. They take the older grounded brush "roundback" (69 / earlier) and "convert" them to isolated brush by drilling a second hole and installing a C.S. brush holder. That in itself is bad enough, along with the brush holders can break, be incorrectly installed or have insulating washers missing, but in addition, these so called "converted" early units can inadvertantly have the grounded brush installed

On the left appears to be a fairly rare piece. This is a roundback that appears to have a factory grounded brush (9 o'clock) and a place for an insulated brush at 3 o'clock which is not installed

squareroundcomp.jpg



Below, is a P.O.S., C.S, smelly, garbage, so called "rebuilders special." This is an early alternator which some off breed, 3rd world rebuilder has drilled the case at 12 o'clock so they could mount an insulated brush and sell this for a 70 / later application. This would be OK except for a whole crapload of good reasons

1....The 69 / earlier units are inferior, outputting less power at lower RPM

2....These modified, drilled brush holders are shakey at best and really shakey at worst

3....These brushholders allow someone to inadvertantly install a grounded brush holder (as this one has at 6 o'clock) ALONG WITH an insulated holder, WHICH WILL CAUSE the problem the OP had in this thread unless the field wires are swapped, in which case you have smokage, burnage, and failage

128306-500-0.jpg
 
You must log in or register to reply here.
-

Back
Top