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Correct Voltage

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Old Nov 12, 2014 | 10:38 PM
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Default Correct Voltage

I was having an issue with my electrical system a few days ago. The Randomly the car would drop from good voltage, about 13, down to around 11 and the check gauge light would come on. No rhyme or reason to it and both the alternator (stock 102 amp) and battery (yellow top from 06) checked good. I figured it was an alternator issue and decided it was a good time to upgrade to the 145 amp truck model. When I first started it up the voltage was at 14.1 and slowly came down to 13.2 or so as I was on a 30 min drive. On the way home it was steady around 13.6.

I'm wondering what my voltage should be at with that alternator so I know if a problem starts to recur again.
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Old Nov 20, 2014 | 01:30 PM
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Originally Posted by DropTopBird
IWhen I first started it up the voltage was at 14.1 and slowly came down to 13.2 or so as I was on a 30 min drive. On the way home it was steady around 13.6.

I'm wondering what my voltage should be at with that alternator so I know if a problem starts to recur again.

those numbers are correct and what you want to see.
a car battery fully charged rests at 12.60 volts not being used, also called open circuit voltage. to properly store a battery and keep it at full charge it should be maintained at 13.2 to 13.5 volts. voltage higher than 13.5 will start to make the water in the battery boil once the battery is at full charge.
a discharged battery that needs to be recharged can accept charging voltage up to 15.0 volts no problem.

for charging the norm is 14.0-14.5 volts and is what old style non-computer controlled alternators are fixed at. for any alternator if you know your battery is good and you start getting system voltage greater than 14.5 volts after engine has been running a while then suspect a problem with the alternator... or a bad ground to the alternator which upsets the voltage regulator and causes the higher voltage.
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Old Nov 21, 2014 | 05:42 AM
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where ever you got your alt from they should give you a certificate of birth.....on it will be the load test information.....if you do not have this or it wasnt given to you than you should go back to the place you got it from and get it and FTR your alternator is just a baby your only gettting 25A more if its the original 120A and 45A if its the ones you get from advanced to replace the OEM ones. Ohio gen makes good ones if your looking for 300A+ but their pricey mine cost in the ball park of 445 with shipping to florida
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