I have been getting the normal voltage #'s of 14.-14.5 when the car is first started for the first 5 mins but after that the voltage drops to 13.5 when driving around. It makes no difference if I turn off the heat, sterep, lights etc voltage stays the same.

I replaced the alternator with brand new one. no difference same thing happens fine for the first 2 mins that voltage drops.

Any suggestions?

 

its not "supposed" to do that, but it happens in just about every car on the roads today.

 

mine fluctuates from 13.6- 14.7volts. could your belt be slipping at all, cause I know mine does every once and a while.

 

makes perfect sense.. you used the battery to start the car.. the voltage regulator in the alt can sense the voltage in the battery and makes the alternator work harder to recharge it quickly. After the battery has been "topped off" it kicks back down to around 13.5 volts or so.. normal running condition.

 

I've been told you don't have to worry unless you drop below 13.2 or so. 12.4 is where I'm at when the car is on, but not started. I usually run consistent with 14.2 but sometimes I'll drop to 13.7-13.9 with radiator fan on and normal driving. No big deal, no reason to change alternator.

 

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Mine runs at about those same numbers too.

I wouldn't worry about it.

 

The voltage regulator I installed definately helped my #'s out in that field. Check out the before and after #'s in my DIY.

 

^^ Are you talking about the voltage stablizer box with a bunch of caps? That removes voltage changes by keeping current steady and providing enough energy for the next spark by storing quickly released energy in the caps. It should make your battery voltage stay constant, not up it any.



Or did you actually replace the voltage regulator on your alternator?

 

The reason your voltage is high when you first start the car is becuase your alternator is cold. The diodes that convert the AC voltage to DC need to be cool to operate efficiently. The hotter they get, the less efficient they are, so your alternator produces a lower voltage or charge rate.

I would not worry about your alternator unless your while running voltage drops below 12.8 volts or so. When you test a cold battery, the voltage should be 12.6 or higher (without the car running). Remember to remove all residual voltage by turning on the high beams for a minute or two before testing the battery. smile.gif

Your alternator is fine gary. Nothing to worry about.