Alternator vs Voltage Regulator - Electrical - Classic Z Car Club Skip to content

Alternator vs Voltage Regulator

Featured Replies

I figured i'd move this convo here:

Question: i recently replaced my ALT and BATT. Measured voltage output from pos. term of ALT to NEG term off BATT: 11.36/38 this is bad right? it shoudl be about 14 or so, if im not mistaken.

Also measured teh neg to pos term of bat: 12.87

this was with the car at idle after running it for about 3-5 minutes. but had to shut car off to opne hatch, than restarted the car. does this make a differeance?

since this is a brand new alternator what is the issue?

-Bad Ground?

-Bad Positive connection?

-is it possible i somehow polorized the alternator with all those wires floating around. (i did connect/install it with no battery in the car, but after battery install i might have touched somethign as the sheilding on the neg wire is bad. (since fixed)

some help please, as this is my daily driver and i drive about 10 miles or so to work...i imagine that my batt will die very soon, if not today

Don't want you to think nobody is helping but that is a weird one... You are for sure running on just battery. I would start with ground connections being that the alt is grounded to the engine make sure the ground wire connection is good and go from there. I'm not much of a regulator guy, replaced all of that with a ZX alt and some rewiring so I'm not sure if a bad regulator would give you those readings... I would think that the alt would be puttin out more even if the reg was bad. Can't polorize an alt just generators so don't think that is the problem.

With a new batt & Alt as previously stated as installed, you are (at least for a short while) going to get at 12+ volt reading across the posts. I have pulled more than one bad or weak alt "out of the box" new. I believe that you might need to try yet another "New" (Remanufactured) alt before you get too much more concerned. If you were driving a 240, I would have recommended an internet upgrade that saved my sanity. Those little 50 AMP alts were not enough. I think that the 280s began running 70 AMP alts. Still not great, and by the way, what kind of sound system are you running? Many of the higher output systems drag low alt output, and ultimately burn-up these dime-a-dozen alts.

Hope that helps-

72 240

Make sure you have the right alternator for the wiring setup in the car (if not original) Don't remember what year they changed, but some have internal regulators, some external....

Ray

  • Author

i tried my 2nd rebuilt ALT. i ahve no stereo...got stolen, thast y all this is happening in the first place. was running fine untill last week, when it got stolen. i purchased a voltage tregulator this evening, having car towed home, as driving at night killed it. runs 8 v's with lights on. over 12 with nothign drawing on it cept for motor

S
Sponsored
Advertisement
Go Ad-Free
No ad showing? Ads help support ClassicZcars. If you use an ad blocker, please consider allowing ads on this site or Go Ad-Free.

Create an account or sign in to comment

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.