Bob - a charging system question??
 

Bob - my car still hasn't produced a charge in the times I've run it. But, I haven't had it out on the road yet. In a previous thread from last spring you suggested wiring in parallel to the red light, a ~20 ohm resister.

What capacity do I need for that resister? The best I could do at Radio Shack was a 22 ohm/.5 watt resister. Anything at 1 watt or bigger and I was getting into a ceramic housed resister like a ballast resister. I'm not sure how much current I should consider this parallel circuit to run. A 1/2 watt resister could only carry mili-amps - I haven't figured it out (volt x amps = watts)

As an edit I will come back and post the earlier thread on this.

http://www.clubcobra.com/forums/era-...ng-system.html

Bob - I'm referring to post #39 in the above.


Thanks in advance

Dan

If you just turn your key on, but don't start the car, the 12.6v in your system, running through a 20 ohm resistor, will result in just a hair under 8 watts by drawing .6 amps. As soon as the car starts, and the VR starts operating properly, there will no longer be a path to ground and thus no wattage at all.

I guess my first post was lost in the other zeros and ones of the net...

Even if the current draw is temporary, I recommend at least a 5 watt resistor. I don't want anyone to make smoke if they inadvertently leave the ignition on too long. I have some ceramic (10W or 20W) resistors in stock if you can't find one locally.

Thanks Bob and Patrick - at least 5 watts then. I suspected I wouild need something a lot heavier than Radio Shack stocks. I'll give John a call this week and order one of your 20 ohm resisters. Can't remember if I cecked continuity on the fuse last Spring either - plan to do that today first.

You know, with electronic voltage regulators Ford used a 500 ohm resistor in parallel around the warning light. It was only on the older style stuff that they used a 15 ohm resistor in parallel. A lot of our OEM looking voltage regulators are really the newer style on the inside, but look old on the outside. I don't know whether you are new or old on the inside.:p But, if you surf the Ford forums, you'll see some people saying 500 or 560 ohms and some saying 15 ohms, and they have their Ford/Autolite documentation in front of them as they write it, and that's the reason. Plus, a lot of people don't use any resistor at all, or don't know whether they have anything in there to begin with. I suppose, in theory, you would want to use the highest ohm parallel circuit around the light that resulted in proper excitation of the VR.

EDIT: An authoritative cite: http://workshop-manuals.com/ford/exp...nd_inspection/

500 ohms - I figured that must be the size of can of soup. But according to this apparently not.

500 Ohm 10W Resistor Wire Wound 5% Tolerance | 016-500

I originally started with an all electronic VR that I believe came from ERA. When my charging issue popped up - and not exactly being a fan of solid state regulators, ignition systems, etc in old cars - I bought a mechanical VR and installed it. Neither one ever worked - so far. Alternator bench tested OK and puts out good voltage in testing. I still have the mechanical VR in it since I like being able to look at something mechanical like points and understand what is going on.

As resistance goes up, wattage goes down. So, at the same 12.6v, a 500 ohm resistor will create less than half a watt and draw virtually no current (less than .03 amps). I think we need to send you back to school.;)

If I haven't said lately that I hate electricity - let me address that omission. Electrical stuff equals :( All I know about electricity is don't stick a hairpin in an electrical outlet - light bulbs are right hand threaded - and volts x amps = watts (which actually does address the above to some extent). I much more prefer working with levers, cams, gears, points, bearings, seals, latches, etc. :p

Patrick - here you go. Talked with John at ERA and he said they have had a couple recent occurances of "failure to charge" in the shop. I think he said they thought it might be due to the supplier using an LED bulb for the charging light now. He had Doug take one of Bob's resisters and rig up a little wiring harness with it - plug and play. Even I can't screw this up. Hope to try it this weekend if the weather warms up a little.

http://i125.photobucket.com/albums/p...ps7144aff2.jpg

That's going to take less than a minute to install. I think you should trot out to the garage and try it right now.

Alas - no joy in Mudville. I installed the resistor in the ignition light circuit toaay and test fired the engine. The light never went out even after reving to 2500 rpm. Back to the drawing board.

For testing, did you jump the regulator plug as described in the Troubleshooting guide?
Did you check that the G/R wire has continuity from the regulator plug to the dash light?

Bob - yes, last winter/ I did all of the tests and checks in the
electrical primer you published and probably a few others that Patrick came up with. Everything seemed good. Here's what I posted at the time on my testing:

"From orange wire terminal on back of alternator to ground for voltage regulator - 12.5 volts (battery geting a little low). No change when I reved it up. The regulator was plugged in.

Unplugging the regulator and jumping the two terminals the voltage from alternator to regulator ground was 14.5 volts and as I reved it, it was climbing to 17 to 18 volts."

Guess I'm going to have to go back to square one and do everything again. I'm also about ready to throw another alternator on it since it's about the only thing unchanged.

Dan

If you are still getting the same reaction by jumping the regulator plug, it's very likely that the alternator is good.

Check that the stator connection (W/B) is correct and the wire from the alternator to the regulator plug has continuity.

I'm going to try and re-run all the checks again this week and see if anything has changed. I did a lot of continuity checks last year but I'm going to also do them again.

Thanks Bob

Some testing results
 

Too cold and windy right now to get the car out where I can run it but I have run through all of the continuity and voltage checks with the engine off.

1. Ignition on/engine off - voltage from Y/P wire at VR harness plug to VR ground - 12.5V

2. Voltage from Y/R wire in VR plug to battery (+) terminal - 12.7V

3. Verified all wires on alternator, VR plug and on fuse box are in the correct position.

4. Continuity W/B wire at VR plug to alternator connection for stator - Yes. Continuity to ground - No.

5. Continuity U/B wire at VR plug to alternator field connection - Yes. Continuity to ground - Yes??????

6. Continuity orange wire at alternator to fuse block at VR fuse - Yes. Continuity to ground - No.

7. Continuity through VR fuse - Yes.

8. Continuity of G/R wire at VR plug to dash light - Yes. Oddly, I have the parallel resistor wired in place and when I disconnected one wire from the light I only had continuity through one of the two leads. It seems like it should have circled through the resistor to the other side with the disconnected lead. May be nothing.

9. Anyone ever toy with testing continuity through a VR. On the solid state one I got no continuity between any of the terminals which may well be because of the solid state hardware.

On the Mechanical Regulator I have continuity as follows:

I to F and S

A none

S to F

F to I and S

Probably means absolutely nothing. I see nothing amiss inside the regulator such as poor solder joints or anything.

Does it seem right that the field connection off of the VR plug shows continuity to engine ground?

Thanks in advance for any observations from this.

I'm not sure I that understand your description, but if you actually have an LED for the light, it will act like a diode.

I pulled one connection to the light and tested continuity to the connected lead and to the disconnected lead. I didn't get a signal on the disconnected lead coming (I think) from the tach. Normally I would not expect to, but I thought with the resistor in parallel to the light, that I would still get connectivity to the disconnected lead from across the resistor. I've used a multi-meter to check ballast resistors in the past to see if they are intact and not burned through.

I guess I need to check continuity across that 5W resistor and make sure it is functional.

The resistor is OK and the light is a filiment bulb. I think I just didn't stab a good connection to it while upside down under the dash. Hopefully tomorrow will be better outside and I can re-run the checks with the engine running.

It's alive!!!!
 

Well - it's finally charging anyway. :) It looks like the resistor did the trick as I ran it with both voltage regulators (solid state and mechanical) and both worked. I think my initial try failed because my optimism in post 9 above was apparently misplaced and I could and did screw up installing the resistor and harness the first time - I think I managed to plug the resistor into itself. That appears to also be why I couldn't get continuity across the light leads that Bob couldn't understand. So much for cramming yourself under a dash and trying to work on little things with bi-focals.