I've been combing throught the posts all week, and I thought that I had found the answer in one of them, but it did not coincide with my shop manuals..

The question is this; I couldn't keep a charge on the 69's battery, so I got a new one, and now it is doing the same thing. Its only a month old...

The Alternator was changed last summer, by my brother who had borrowed the truck, and its putting out 14 volts as far as we can tell. (I'm leaving work early to check that for certain) but I remember seeing a post that mentioned a Voltage Regulator somewhere in the system, and that it was an inexpensive part to change.

I looked for it in Chiltons and Haynes, but could not find any mention of it???

Was the post possibly referring to a later model with an elec ignition?

Any help and guidance is appreciated.

Unfortunately I am somewhat of a by-product of the information age. I learned to shadetree on OBD I & IIs, the 69 Ranger was a 302 that Dad swapped for the 390, It has sat pretty much all of the 4 years since he passed, and I am now ready to start on restoring it, But I want to drive it too..

The simplicity is somewhat strange, and the answer is probably right in front of my face, but at the risk of looking foolish, I wanted to ask for more opinions..

 

There are two options regarding the voltage regulator.

One, the regulator is internal to the new altenator you put in last summer. If it is, the output will be around 14.7 volts and connected to battery.

Two, the voltage regulator is external (original configuration) and there should be a couple of leads from the altenator to the regulator. (a box containing a rectifier circuit) this rectifier circuit changes the AC output of the altenator to a regulated 14.7 DC output, then this DC output goes to battery.

You mentioned you are getting 14 volts output from your altenator. Where are you measuring this from. It sounds to me that the rectifier is working, whether internal or external.

 

I'll definitely know more this afternoon, its my 20 year old brother who took the readings, and frankly, I'm not sure where he got them from.

I'm going to take multimeter readings from the posts on the alternator, and from the battery posts while running at 2000 RPM and idle to see what we're dealing with.

Thank you for your feedback! I'll let you know what I find out.

 

[updated:LAST EDITED ON 01-Mar-02 AT 12:17 PM (EST)]Perhaps this will help.

This is of a newer system but the difference is,
This VR is transisterized and your original VR isn't .

https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1730&.jpg




Dennis https://www.ford-trucks.com/user_gallery/sizeimage.php?&photoid=1733&.jpg



Please Don't Ask Me Any Tough Questions,
"I'm Saving My Memory For When I Develop Alzheimer's"


78 F-150 429CJ,Silver, Explorer Pkg.
641/2-Mustang 260,Pre-World's Fair Car.
64-Fairlane500 S/C waiting for a 390-4spd.
68-Mustang 289-Sunlit Gold 80,892Mi
78-Buick LeSabre 403 4V
84 Volvo DL Wagon

 

The charging system may be working properly. Maybe you have a discharge condition when the key is off. While you’re taking readings with the multimeter, try this. With everything off, disconnect the negative battery cable and put the meter between the cable end and the battery post. Set it for 10 Amps to be safe, you can work the scale down from there. There should be no current flowing when everything is off. If there is, unplug the voltage regulator connector and retest.

Rcbisset, I thought the rectifier circuit was built in the alternator, the six diodes. The regulator controls the field current to regulate the output voltage level which is already rectified.

Barry

 

Barry,

You are probably correct. My assumption was that the bridge rectifier and regulator was housed together within the regulator box as shown on the previous post drawing. MY BAD.

Do all altenators have the rectifier circuit built in?

rob

 

An old method of checking to see if your system's charging is to hold a screwdriver to the rear bearing cap on the alternator with the engine running. If there is a magnetic draw on the screwdriver, it should be charging okay. If not, it's a bad alt, reg or the circuit. The regulator for all these old trucks is mounted to the right of the radiator.

 

Thanks Everybody!

Here's the findings, the system is definitely charging, pushing between 14 and 16 volts if my meter was right.

I'll check the discharge next..