[mashedfinger67]

Okay, where's George at?............

I have just finished wiring all of the new stuff into my '67. I didn't want to end up hacking all of the factory wiring up so I simply added a "secondary" stand-alone system with all of the new stuff being run off of either bosch-style relays or a new 6 circuit fuse box. I have used the combined run/start signal from the existing coil + wire to switch the relays and have added a master disconnect switch that disconnects the entire electrical system from the positive battery terminal.........which leads me to ask the following question;

Since I have wired the charge circuit from the alternator, which is 3-wire, to the 175A junction (see quicky schematic below) instead of directly to the positive battery terminal, when the car is running will power be disconnected from the alternator shutting the motor off when I open the master disconnect switch?

...................Or will I need to run the charge circuit directly to the postive battery terminal to accomplish that?




Thanks in advance for any input!!!

["QUICK-SILVER"]

??
Do you still have original battery cable to starter?
If so, you have (2) two battery supplies going to your new setup. The disconnect will not do anything.

If the disconnect is in the starter cable, I see another problem.
Your schematic would have the starter cable going through a 175 amp junction.
Starters can pull way more than 175 amps.

[george kujanski]

Hi there...here I am.......as QS says, unless you have an addiditonal heavy cable from the battery to the starter, running the starter current thru the 175A junction is not good because the starter can draw 400 A or so. Secondly, turning off the master switch as you show is not a good idea for the following reason: the alternator is intended to run in a system with a bettry connected because the battery acts as a kind of filter. Disconnecting the battery while running may cause the alt output voltage to spike, damaging electronics, and yes, the car will continue to run (if the ignition system , HEI or other) doesn't get killed in the process.

Forget the disconnect switch (while running), and provide a separate heavy cable to the starter, and your circuit will be ok.

Master Disconnects for NHRA rules in this application have a separate set of terminals to shut down the alternator circuit if that's why you need the Master Disconnect.

George

[mashedfinger67]

Quick Silver and George, I appreciate both of your input alot. The intent of the disconnect is to be able to take power off the car (hidden, keyed type disco) to make sure that is remains mine and not some crooks. I thought I could kill two birds with one stone and, if at all possible, make it an emergency disconnect as well


Some clarifications below:

1. I do not have the original battery cable to the starter.
2. I have the new cable to the starter from the line/input side of the 175A disconnect even though my quicky schematic incorrectly shows it feed from the load side (across the fuse). Both the battery cable and starter cable are #2 CU battery cables from NAPA

So, I think what I am getting is this: As shown, my HEI will lose battery power when the disconnect is opened, but with the alternator charging circuit run to the 175A junction as shown, it will still get alterator power and continue to run, correct?

So all is good and fine as long as I only use the disconnect for an anti theft device.

OR

I re-route my alternator charging circuit (see new quicky schem. below) from the 175A junction to a direct connection to the battery, and then my disconnect should then properly function as a master disconnect as well by removing battery and alternator power, effectively (and safely) shutting of the car while running?

Thanks again gentlemen.

[george kujanski]

The new schematic looks good. On the existing system there should be a fusible link or fuses also. Power to the car will be cut off when using the disconnect.

George

[mashedfinger67]

George

I haven't touched the existing wiring loom, so it has whatever the General intended it to have as originally equipped. I have run the alternator charging circuit to the battery with a 10 ga. wire, and will splice a fusible link into it as well.

Thanks for the input as usual, you are a credit to PY and I always appreciate your effort!

["QUICK-SILVER"]

Better!

Would still use disconnect for anti theft device only.

I cannot recommend using the disconnect as a kill switch. Not without seeing voltage regulator wiring.

[mashedfinger67]

Originally Posted by QUICK-SILVER

I cannot recommend using the disconnect as a kill switch. Not without seeing voltage regulator wiring.

It is the wired per the factory harness if that makes any difference.

Thanks Quick!

["QUICK-SILVER"]

New system looks good.
Common links were my only concern, possible feedback issues.
Lets hope not, but if you should have an electrical problem, in the future, old and new circuits may be connected in many places and also share one ground.
Keep a ledger on everything you do, it will be of great help if you ever have a problem.
Note where all old and new circuits meet, not just the obvious like regulator and trigger wires but also guage lighting, sending wires, etc.

You can definitely call this baby yours.

[mashedfinger67]

Originally Posted by QUICK-SILVER

You can definitely call this baby yours.

Well thanks Quick, that's a he!! of a nice thing to say to a guy like me.


BUTT, after relocating my alt. charging wire from the 175A juntion to the battery, my drivers tail light stays on, even with the master disconnect off. Which I do not get at all, as the master disco takes away any and all connection from the + battery terminal to the system!

I was an avionics tech on boeing E-3's in the USAF years ago, so I understand some DC theory (and, if all else failed, could R2 a box in nothin' flat ). I thought it might be backfeeding through a ground? But if so, -especially with the + terminal of the battery totally isolated from the system, how?

...........I thought I had it licked, too!

["QUICK-SILVER"]

My fears exactly.
One tail light on may be easier to fix than you think. Especially if all rear lights work correctly under normal conditions. If power is getting to the left rear brake/turn wire only, it's a single wire from the turn signal switch to the back. Should be easy to trace.
Or, have you tried moving turn signal lever to see if light would move? Just a thought.
If it does move, power is feeding back through a factory shared wire between ignition switch and bulkhead.

Alternator 2(R) or 1(F) could still allow power back into system, even with disconnect open.
Haven't seen it in all, but some SI's have a ressistor on top of the regulator. This may be your culprit.
Unplug the voltage regulator and see if the light doesn't go out.

Do some testing and let us know what you find.
Can't be as bad as replacing brushes in gear reduction motor on auto pilot servo.
Good luck keep us posted.

[mashedfinger67]

Thanks again Quick, I will dig around and see what gremlins I can chase out of my tail lights.

[v8drinker]

Originally Posted by QUICK-SILVER

Alternator 2(R) or 1(F) could still allow power back into system, even with disconnect open.
Haven't seen it in all, but some SI's have a ressistor on top of the regulator. This may be your culprit.
Unplug the voltage regulator and see if the light doesn't go out.

Preface: I don't know what I'm talking about, but read on...

I'm curious as to how you have your alternator wired since you say you have a three-wire alt, but the schematic shows external voltage regulator with only one wire coming out.

I think there should be, besides the big wire, 2 small wires coming from your (internally regulated) 3-wire alt: The red one (sensing) should follow the big wire to the power junction, and the brown one (field) is the ground wire for your charging system warning light, which also gets switched ign power.

When the car is running, the alt sends power to the field wire so the warning light has no ground and goes out.

I recently added gauges and rewired my dash...thought since I was adding a volt gauge, I could do away with the idiot light. Found out that it's actually part of the alt voltage regulating circuit.
So I tried to just bypass the idiot light by running a jumper from ign to the alt field wire. Wrong! The car started and ran but when I shut it off and removed the key from the ignition, it kept right on running...the alt field wire was providing power through my jumper to the ignition and the car wouldn't shut off!
When I replaced my jankey jumper with a regular warning light, everything works fine since the light won't pass enough power to run the car.

So in my experience yes, alt field wire can supply power to the system, with or w/o a disconnect.

[mashedfinger67]

Originally Posted by v8drinker

......you have a three-wire alt, but the schematic shows external voltage regulator with only one wire coming out.

Ah, V8drinker you have taken my schematic a little too literally! It is just a quicky schematic with a focus on how I wired power to my new accessories. The only reason I even included the voltage regulator on the schematic was just to show that I got's me one.

Sorry for any corn-fusion this may have caused you. I appreciate your input on the dummy light, I have read other such happenings in my research prior to making my decision on the design of my new wiring and that is one of issues I am hoping to avoid by leaving the existing wiring as is and installing all new stuff on a secondary system.

.............but, just in case. How did you get it to shut off? Yank the HEI wire? Unplug the alternator? show it pictures of my mother-in-law in a tube top? (that last one there would turn anything off!).
.
.
.

[george kujanski]

What v8drinker says is true, and typically presents a problem in systems using, say, a MSD box which uses an ignition wire to power up the box. The box main power is connected directly to the battery. In the above scenario, enuf current goes trhu the idiot lite with the key off, to keep the MSD box turn-on circuit alive. It also will keep a relay coil pulled in, for those folks using relays to interface to other "accessories" like HEI.

George

George

[v8drinker]

Unclipped the jumper and it shut right off. Just kinda testing things. Wired it up right after that, it looks nice works right, I'm proud. Now I'm battling my carb, this car humbles me every time I touch it.