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Alternator charging too much.

Started by Racer57, March 30, 2020, 07:41:10 PM

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Racer57

Alternator shows 14.9 at idle and goes up too 15.8v  No headlights or anything on.   Bought new regulator and it shows the exact same.   I've never had a reason to check the alternator in past because I had no reason to suspect anything wrong until I had the amp gauge changed to volts and thats when I noticed something wasn't right.  This is the alternator I have if that tells you guys anything.  Would the wrong size pulley cause it ?   Is it overcharging enough to cause problems ?

dodj

If you are wired in stock configuration, high resistance connections at the B/H connector can cause that. It's like this. The alt puts out, for example 14.2 volts. A high resistance connection at the B/H can drop, lets say, 1.2 volts. Now the VR sees 14.2 - 1.2 = 13.0 volts. So the VR ups the output of the alt to 15.4 because it wants to see about 14.2. (15.4-1.2 = 14.2)
Clean your connections and you will likely find your charging goes back to normal. If not corrected soon enough, it is this situation that melts the B/H connector. Poor connections (voltage drops) cause heat.

"There is nothing your government can give you that it hasn't already taken from you in the first place" -Winston Churchill

Racer57

If it makes any difference, I do have a bypass wire from alt to starter relay and theres no change whether its hooked up or not.


JS29

Confirm your voltage regulator is grounded.  :alan2cents: 

Racer57

Quote from: JS29 on March 31, 2020, 07:56:23 AM
Confirm your voltage regulator is grounded.  :alan2cents:
braided strap from it to intake bolt.

Chryco Psycho

Pulley size makes no difference as the regulator should keep it in the right zone , do you have a volt meter to double check the voltage at the battery ?