High Voltage Output

[thilmes]

Hello all.

I need a little sleuthing here. 1970 T. Car was not running when I purchased. Following much work car ran well. Only remaining problem was system was not charging. I purchased a Hella regulator from Pelican. other posts here show others using same regulator with success. All worked fine then the battery boiled dry! so, cleaned it up and checked voltage. about 18 V. replaced regulator with identical unit. back to about 14V. after 100 miles or so problem has re-occurred. running about 18 V.

So, vehicle is parked so as not to do damage. I could use a little help. What is causing the regulator failure? I do not know any details about the alternator...

I searched the forum and did not see this particular issue addressed.

Possible issues??:
alternator diode failed ? would this cause what I am seeing?
two faulty regulators? i doubt this...
bad alternator?
mismatched alternator/regulator? Im not feeling this
Highoutput alternator to much for regulator?

I look forward to your thoughts!

[M_deJong]

I think you need to examine the alternator and the wiring. Something is overloading the voltage regulator. My guess is a partial short in the wiring or the wiring is connected wrong at the alternator (like +12V at DF), or a bad ground.

The VR only works on the field coil side of the alternator so bad diodes etc which affect the output (usually by lowering it) should not harm the VR.

[304065]

You are sending full field somehow. Intermittent nature suggests either a problem with the wires, like you somehow have the B+ and DF wires touching in the back of the alternator, or defective VR. Try a Bosch instead-- although these days they are all probably the same solid state chip potted in epoxy.

[thilmes]

update: i pulled the alternator to ensure that the wiring was correct. it was. i inspected all the wires for shorts/grounds. there werent any. I then inspected and cleaned all the pin terminal connections. I also made my best guess again at the proper connection to the regulator. it is the new solid state type and the pin configuration is not very clear to me. i do not think i modified the connections. i then put it all back together. i think the only thing i really did was ensure the pins connectors were clean. started it up and voltage was back into the acceptable range. weird. i am guessing it was a poor connection in the multi-pin connector... thanks for the comments!