Alternator / Voltage Regulator

Large Arbor · #1 (**permalink**) 08-17-2015, 12:19 PM

I hve a new battery and seem to be having issues keeping it charged. I am going to replace the volatge regulator and alternator to rule out sources. The OEM replacement voltage regulator is $100. The aftermarket Regitar GR341 is $10. Any reason to go OEM?

The alternator I have is a Cobra Valley 80 Amp variety and has 4 wires. See pic. I would like to go to a single wire and bump up the amperage. Any recommendation on what to use? I am trying not to replace mounting, pullies, etc. I ordered the exact replacement, but it is 4 weeks out. Has anyone had success with the single wire? If I have an external regulator do I have to stay away from the single wire versions?

Phil

ffr 1137 · #2 (**permalink**) 08-17-2015, 12:44 PM

The one-wire has an internal VR. You can either give the harness a diet or
simply unplug the VR. Make sure you don't run with it connected. It will work
UNTIL the VR decides to die but when it does it drags your 12v down too low (like about 4v) and your car dies. Ask me how I know. Noon in Phx on the stack, 106deg, 80mph in HOV lane and lost everything.

Mike F

DanEC · #3 (**permalink**) 08-17-2015, 01:10 PM

Phil - if you bump the amperage further with a 1-wire alternator, you may want to consider switching the amp gage out for a volt gage too. All that amperage goes through the gage. I think in addition to doing away with the external VR that you also lose the red light charging circuit. If you keep the 4-wire alternator, the solid state voltage regulators should work as well as the older mechanical points type.

Have you taken any voltage readings with the motor running?

jhv48 · #4 (**permalink**) 08-17-2015, 01:47 PM

Before you go replacing anything first verify with a multi meter that the battery isn't getting a charge from the alternator.

Your ammeter should also be reading in the negative.

Large Arbor · #5 (**permalink**) 08-17-2015, 07:19 PM

Ok, I will take some readings. The Ammeter has not worked since day one. Tried reversing the terminals and it made no difference.

I will take some readings and go from there.

Phil

DanEC · #6 (**permalink**) 08-18-2015, 06:06 AM

This sounds like an opening for the ERA Electrical Wizard (Patrick) to step in with some timely trouble shooting tips.

davids2toys · #7 (**permalink**) 08-18-2015, 07:22 AM

Quote:

Originally Posted by DanEC

This sounds like an opening for the ERA Electrical Wizard (Patrick) to step in with some timely trouble shooting tips.

Agreed....bring on the Guru!

Large Arbor · #8 (**permalink**) 08-18-2015, 07:33 AM

Here is my thoughts. The battery is obviously losing charge when its running. Thus it can only be the voltage regulator or alternator as other than the fan, nothing else is running. The fan draws less than 20 amps and the alternator puts out 80 amps. If the Voltage regulator is working properly then the alternator would charge the battery. I will take readings, but when I came home the battery was reading around 10.75 V. I charged it and it is now reading 12.5 V. With everything else off, except the fan, and the battery not draining when its sitting, I conclude the alternator is not sending the necessary current to the battery to charge it. The external voltage regulator controls that thus my conclusions above.

Phil

DanEC · #9 (**permalink**) 08-18-2015, 08:33 AM

If I remember correctly, when my VR was not "stimulated" to start "regulating" (maybe it needed Viagara), and I was getting just 12 volts out of my perfectly good alternator, which is not enought to charge the battery other than when it is discharged down to below somewhere around 9 or 10 volts. In other words the VR wasn't telling the alternator that it needed to step up to 14 volts output in order to charge the battery. As I recall the roughly 14 Volts charge is necessary to overcome the roughly 12.7 volts in a battery and actually begin to charge it. With the 4 wire alternator, the circuit to the VR that comes from the red light on the dash, somehow "excites" or stimulates the VR into action. So, if your red light is not glowing but you only have 12 volts out of the alternator when the motor is running - I would be looking at a new VR. If the red light is on while the motor is running then there may not be enough resistance in that circuit to the VR to turn it on. ERA provided me with a resistor to wire in on the red light "charge" circuit to get mine working.

However, if Patrick is out there he can provide a much more comprehensive trouble shooting process.

Large Arbor · #10 (**permalink**) 08-18-2015, 10:18 AM

Thanks for the info so far. My red light only has ever glowed when I turn the key on. After starting it has always gone out Its been that way since I have had the car. I tend to think the voltage regulator is the culprit.

Phil

DanEC · #11 (**permalink**) 08-18-2015, 10:48 AM

More than likely that's correct. For the price of a solid state voltage regulator it's worth trying. As long as you ground the case to the frame you don't even have to install it in place to test it out.

Large Arbor · #12 (**permalink**) 08-18-2015, 11:33 AM

Had both alternator and VR tested together and the VR is bad. The alternator was ok, but I will replace it as well in a couple of weeks. I also picked up a 12V led flasher. You simply hook a 12 V source to it and it flashes. All one component and very bright. Patrick would be proud!

Phil

patrickt · #13 (**permalink**) 08-18-2015, 01:19 PM

Quote:

Originally Posted by Large Arbor

Patrick would be proud!

Phil

Yes, Patrick is proud.

You might consider ditching your ammeter if it does not function properly. You can bypass it safely from the engine side of the firewall if you're hesitant about crawling up behind the dashboard and yanking out the ammeter wires.

Large Arbor · #14 (**permalink**) 08-18-2015, 05:09 PM

Actually, I woud like to convert the ammeter gauge to a voltmeter gauge. What would I connect to register voltage? Battery?

Phil

patrickt · #15 (**permalink**) 08-18-2015, 06:30 PM

Quote:

Originally Posted by Large Arbor

Actually, I woud like to convert the ammeter gauge to a voltmeter gauge. What would I connect to register voltage? Battery?

Phil

A volt meter is the easiest gauge in the world to hook up. You can run it off of virtually any hot lead that is under the dash, or off the ignition switch post, or the battery, or the master circuit breaker on the firewall over by the starter solenoid -- any of those, or the cigar lighter feed, the fuse box, etc. Super easy. Bypassing the ammeter is just slightly more difficult, but not much.

patrickt · #16 (**permalink**) 08-18-2015, 06:40 PM

Really, your toughest decision is whether you want the volt meter switched or not (meaning, do you want the gauge displaying the volt level with the key off). You generally have it switched in most cars, but I've seen a couple of Cobras that have it wired hot all the time, but have a battery disconnect (which most of us have anyway). There are handy advantages to having it hot all the time but you just disconnect the battery when you're not driving the car. It's up to you.

strictlypersonl · #17 (**permalink**) 08-19-2015, 05:51 AM

A voltmeter draws very little current. My preference is simply to run a wire from the accessory terminal of the ignition switch (or from the power wire of the fuel gauge) to the voltmeter.

davids2toys · #18 (**permalink**) 08-19-2015, 06:34 AM

Quote:

Originally Posted by Large Arbor

Had both alternator and VR tested together and the VR is bad. The alternator was ok, but I will replace it as well in a couple of weeks. I also picked up a 12V led flasher. You simply hook a 12 V source to it and it flashes. All one component and very bright. Patrick would be proud!

Phil

Phil,
What else do you need to hook up this flasher? Always bothered me that the car does not have flashers. I was spoiled because my first Cobra had them. They saved me one night when the fuse on my headlights decided to blow. Drove home with a flashlight(friend was holding it shining on the shoulder so i would not go off the road). Also, when I first got the car, the fuel gage wax off and I ran out of gas. Godsend when you are stuck on the side of the road, especially in such a small car that could be hard to see!
I remember seeing/posting to a thread about how to put flashers in, I think it was Patrick's, it was involved and scared me because I hate electric in cars. Definitely not my strong point.

patrickt · #19 (**permalink**) 08-19-2015, 06:49 AM

Quote:

Originally Posted by davids2toys

I remember seeing/posting to a thread about how to put flashers in, I think it was Patrick's, it was involved and scared me because I hate electric in cars. Definitely not my strong point.

My four way flasher installation thread, with pics: Four Way Flashers -- How To with Pics

Large Arbor · #20 (**permalink**) 08-19-2015, 11:18 AM

Aside from the work with Patrick's thread, the flasher I bought simply plugs into a 12 V source and then flashes LED's very brightly. I was hoping it fit in the backup light, but it does not. I think I will put a 12V circut to the trunk with a switch on the dash and just let it hang from the trunk if it is needed.

I first have to wire the Voltmeter gauge I ordered. Like you having a flasher helps, but its just used so infrequently, my option will be very easy to do.

Phil