Ammeter/Charging Issue and Question

Samplingman

Samplingman

Old Man with a Hat
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So I've had the TX9 '70 300 running for a few years now and never realized alternator was not charging the battery. For some reason I only had the green wire plugged in thinking it was a single field system. Apparently I was looking at the '69 alternator I have in the 'vert thinking it was the same and had the wrong alternator restored for the 'vert, but of course they went to a two wire system in '70, so that's all screwed up.

Anyway, back to the TX9, I replaced the brushes, installed a new adjustable VR, connected the blue and green wires and magically the alternator started charging!

Questions:

1 - although it's charging I'm seeing some strange things. With the car not running, the battery is at 12.54 volts; car running and I'm at 13.5 volts (good, right?) but the ammeter is a hash mark above center; car off after a minute or two and the battery now ready 12.77 volts. Is this OK, or am I over charging the battery? I thought the VR is supposed to cut the alrernator off after charging the battery?

2 - can a '69 single field alternator be converted to use both fields, or am I looking at getting the correct 1970 alternator for the 'vert?

Thanks in advance for any commentary.
 
The regulator does not cut off charging to the battery, it maintains a set voltage as referenced on the ignition 1 (blue) wire at the regulator while running. The state of charge of battery determines rate of battery charge current. If the battery is healthy and at a full state of charge, there should be little to no indicated charging current registered on the ammeter. A failing or other issue with the battery can show an abnormal charging rate, hence the reason and purpose of the ammeter. Misplaced loading at the battery will also show a false charging indication on the ammeter as well. Any added running loads connected at the battery/starter relay that shouldn’t be? I would start by having the battery load tested. Yes, it can take a few minutes for a health battery to return to 12.6 volts after shutdown.

’69 and earlier alternator cases have one field brush grounded, ’70 and up require both brushes to be insolated from the case, would be more work than its worth to try to covert an older case.
 
72RoadRunnerGTX said:
The regulator does not cut off charging to the battery, it maintains a set voltage as referenced on the ignition 1 (blue) wire at the regulator while running. The state of charge of battery determines rate of battery charge current. If the battery is healthy and at a full state of charge, there should be little to no indicated charging current registered on the ammeter. A failing or other issue with the battery can show an abnormal charging rate, hence the reason and purpose of the ammeter. Misplaced loading at the battery will also show a false charging indication on the ammeter as well. Any added running loads connected at the battery that shouldn’t be? I would start by having the battery load tested. Yes, it can take a few minutes for a health battery to return to 12.6 volts after shutdown.

’69 and earlier alternator cases have one field brush grounded, ’70 and up require both brushes to be insolated from the case, would be more work than its worth to try to covert an older case.
Click to expand...
Ok, thanks. It is a new battery 8/25 date, but of course it was run down a bit. Does it matter which ignition wire is attached? There are three blue wires in the harness, two come from the ballast, and one looks like it was on the electric choke, I might have the wrong wire on there.

I kind of figured I'd need another alternator with the insolated fields, thanks for confirming before I really mess things up.,
 
Definitely, a healthy battery in a low state of charge will draw some current for some time until it reaches a full state of charge. No factory electric chokes in ’70 but there are several other items on the ignition 1 circuit in the engine harness, blue or dark blue is the common color code for that circuit. Assuming a stock harness, there is no reason to think the wire is misplaced at the regulator plug. At the alternator, one of the field wires is on ignition 1 as well. Functionally, it doesn’t matter which field wire is connected to the two field terminals.
 
Thank you you for that explanation, wiring is my downfall with these cars. The carb was replaced with an Edelbrock with an electric choke. The wire was not hooked up and long enough to reach the alternator so that's what I used. I'll let the car run for awhile and see if the ammeter settles down. The wiring in this car is kind of hacked and burned in places, that's one of the reasons it was originally going to be a parts car. My son is intent on running new wires and getting it going.
 
Another question, this time about my convertible. I replaced the single filed alternator with a two field, replaced the brushes and connected the correct wires. Before starting, the battery was at 13.5 volts, I thought that was high. It was on a battery tender, but that was disconnected a couple of days ago. It started strong, charging at 15.7, ammeter was just above center. Got the car to idle and charging settled at 15.4 ammeter was steady. After shutdown, the battery was once again at 13.5. I don't want to cook anything, but the car seemed to run better and smoother than ever.

Shouldn't the charging while running voltage be lower? Should I adjust the VR to a lower setting? Why would the battery retain 13.5 volts? Should I just not worry about this?

Thanks.
 
Well I did another test, charging at idle at the battery is 15.4, charging at the ignition wire and ground at the ballast is 14.4. So, still overcharging at the battery. I remember reading the difference should only be .5 volt. Also saw somewhere that swapping out the old ignition switch will solve the problem of overcharging at the battery. Can I simply adjust the VR to lower the voltage at the battery? My battery is staying at 13.1 overnight.
 
Thanks, that video is extremely helpful. I totally agree with resolving the core issue. Temporarily I adjusted the VR to
its lowest setting, 14.1 at idle, a lot better than 15+. It’s been a few years, but when I put the column together I was very meticulous about cleaning connections, I will run through them again. The relay is an interesting solution I’ll be looking at that closer as well.
 
First generation Chrysler alternators grounded one brush and mechanically, regulated the voltage to the other brush. Being that they were mechanical, these regulators were adjustable. It's pretty much the same technology used in generator voltage regulators. Bend a tab to increase or decrease the voltage, adjust the contact gap, etc..

The later, electronic, regulators operate by supplying 12 volts (the same blue wire circuit that powers the regulator) to one brush and the voltage regulator varies the ground potential of the other brush to regulate the voltage. There isn't any adjustment possible aside from modifying the harness between the regulator and the alternatorn to fake out the sensing circuitry.
 
ynst said:
First generation Chrysler alternators grounded one brush and mechanically, regulated the voltage to the other brush. Being that they were mechanical, these regulators were adjustable. It's pretty much the same technology used in generator voltage regulators. Bend a tab to increase or decrease the voltage, adjust the contact gap, etc..

The later, electronic, regulators operate by supplying 12 volts (the same blue wire circuit that powers the regulator) to one brush and the voltage regulator varies the ground potential of the other brush to regulate the voltage. There isn't any adjustment possible aside from modifying the harness between the regulator and the alternatorn to fake out the sensing circuitry.
Click to expand...

I installed a Transpo C8313 adjustable solid state VR that I am able to adjust the voltage to the battery, but it would only adjust down to 14.1. I’ll clean the contacts and re-test.
 
Ok I think I’m satisfied. I cleaned and used de-oxit on the bulkhead and Molex connection under the column. I now have 13.9 at the battery and 13.3 at the ignition wire on the ballast resistor. I also checked with the headlights on and I get a steady 13.5 at the battery. No time now to rip into the column for the ignition switch, but I think I’m safe to drive it right now. Thanks again for all your help!
 
stupid suggestion...have you tried a different voltmeter? the fact that both resting and charging voltage are a volt too high could be an inaccurate meter
 
im not very much savvy for online things, so i dont even know how to begin a thread...but this thread is very similar to my current dilema. If i may impose, i will. recently got my 65 383 back together, turned on key & hit the momentary switch...VROOM, for 1 second,
then nothing. i have no spark, with this set-up:
stock voltage regulator, GM 100amp Alt, MSD StreetFire & MSD Blaster2 coil. HOW TO CORRECTLY WIRE THIS STUFF BACK TOGETHER ? As i drove it like this for 2 years, i know the set up is viable. Finding wiring diagrams for such a mix is next to impossible.
 
hell I don't know how to wire an MSD either but I'm sure you can contact them for wiring diagrams...in the meanwhile start simple, get a test light and look for 12 v from battery to starter relay to key to ballast resistor to + coil...bulkhead connectors are notorious for bad connections and moving stuff around installing the engine could cause no power getting inside the car or back out to engine compartment...if you have power at + coil terminal , then the issue is in the "points" part of the circuit that triggers the coil to fire...in your case the MSD system or how its hooked up
 
shaun65Polara said:
im not very much savvy for online things, so i dont even know how to begin a thread...but this thread is very similar to my current dilema. If i may impose, i will. recently got my 65 383 back together, turned on key & hit the momentary switch...VROOM, for 1 second,
then nothing. i have no spark, with this set-up:
stock voltage regulator, GM 100amp Alt, MSD StreetFire & MSD Blaster2 coil. HOW TO CORRECTLY WIRE THIS STUFF BACK TOGETHER ? As i drove it like this for 2 years, i know the set up is viable. Finding wiring diagrams for such a mix is next to impossible.
Click to expand...

Given the 1 second of "VROOM" I suspect the Streetfire unit failed. Did you look to see if something like the coil came loose? A wire coming loose would act like this, or, an ignition switch. Try hotwiring it, then turn it over, IFF no loose wires show up.
 
shaun65Polara said:
im not very much savvy for online things, so i dont even know how to begin a thread...but this thread is very similar to my current dilema. If i may impose, i will. recently got my 65 383 back together, turned on key & hit the momentary switch...VROOM, for 1 second,
then nothing. i have no spark, with this set-up:
stock voltage regulator, GM 100amp Alt, MSD StreetFire & MSD Blaster2 coil. HOW TO CORRECTLY WIRE THIS STUFF BACK TOGETHER ? As i drove it like this for 2 years, i know the set up is viable. Finding wiring diagrams for such a mix is next to impossible.
Click to expand...
Here's the instructions off the MSD site for the Streetfire ignition. https://documents.msdignition.com/5a4a0872264ea7873ff3abc3ca44cc925cba2d5e.pdf

Regarding the GM alternator, those are usually one wire units where the voltage regulator is built in. Is that what you have? The stock voltage regulator isn't needed and probably not helping if that is the case.

All that said, MSD doesn't have the greatest reputation any more. Their stuff used to be the best, but then they were sold once or twice and now Holley owns them. So it would not surprise me at all if the MSD unit failed, but that's just speculation on my part.
 
Big_John said:
Here's the instructions off the MSD site for the Streetfire ignition. https://documents.msdignition.com/5a4a0872264ea7873ff3abc3ca44cc925cba2d5e.pdf

Regarding the GM alternator, those are usually one wire units where the voltage regulator is built in. Is that what you have? The stock voltage regulator isn't needed and probably not helping if that is the case.

All that said, MSD doesn't have the greatest reputation any more. Their stuff used to be the best, but then they were sold once or twice and now Holley owns them. So it would not surprise me at all if the MSD unit failed, but that's just speculation on my part.
Click to expand...
thanks guys, i will follow up on all suggestions
 
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