[Maverick Memphis]

I have an Elantra gt 2013 that battery light came on and started dying while driving.
Battery tested good and I replaced the alternator. The alternator is dropping once the car starts.
Replaced with a second one and doing the same.

are the alternators bad or something else going on?

 

[Drunken Elvis]

More information is needed. What is meant by the "alternator is dropping"?

Is the battery light illuminated with the new alternators?

This is a smart charging system [ECM controlled]. When the battery is fully charged, the computer sometimes drops voltage to aprox 12.6 volts. In order to save energy and not overcharging the battery.

The alternator usually has a secondary voltage regulator built into the alternator itself. If you unplug the small wires from the alternator, the secondary voltage regulator takes over raising the voltage to aprox 14.5V even if the battery is fully charged. This is one test of the alternator.

 

[oragex]

You may have a short somewhere, maybe inspect closely the starter cables - tight and no corrosion

 

[Maverick Memphis]

Found out both alternators weee bad that were reman

 

[Muzzammil]

Found out both alternators weee bad that were reman

Which remanufacturer was that?

 

[Maverick Memphis]

Autozone’s reman. Guess from now on I’m just getting new ones

 

[missingcurlybracket]

Reminded me of this memorable thread: https://www.reddit.com/r/cars/comments/zvz9sg