The alternator on my 1993 infiniti j30t went so i bought a new one and had it installed about 2 weeks after having it installed it went again so i figured it was just a faulty alternator so i brought it back and got another one cause it was under warranty i had the 2nd one installed and about a week later it went again, i am at the point now idk what to do cause i doubt i got 2 faulty alternators back to back like that, could there be something else wrong with my car causing the alternators to fry? if this helps any i got my alternator from autozone with the lifetime warranty could it just be the alternators that they carry cause i dont want to have to buy a new alternator through the dealership and have it die on me a week later, i just dont know what to do at this point so im just reaching out looking for some advice or maybe someone on here has had the same problem with their alternator on their j30, thanks in advance for any helpful info you can provide i have only owned the car for about 4 months so i dont really know much about it

it is very likely you got two faulty alernators back to back from a retail location like autozone.
Have it tested prior to leaving the store....then after installation, have the charging system checked out to make sure the charging system is working correctly.

I have heard folks complain about non oem alternator. The first duralast that I got worked fine as has been going 2 years. I do know that the j's require guitar string tight belts and if there is any squealing at all it won't charge right. But it sounds like something else is going on besides alternator. A dead or uncharged battery is not always a tell tale sign. Either test it at the store or if installed your battery battery should be at least 14 volts with the car running.

Are you sure they are fried? On my J, I thought my rebuilt alternator was bad, but it turned out to be corroded connections in the main fuse & relay box in the engine compartment. I only discovered this when I went to take apart that area. The corrosion was hidden from view. Cleaned up contacts & never had another electrical problem!

I'm not sure on the 1993 J30s, but the driver's manual in my 1997 J30T glove box has a specific warning! If you are not going to drive your car for 4 or 5 days, disconnect the battery! There are so many monitor circuits that there is a constant drain on the battery. P,S. Standby chargers that plug into the cigarete lighter will not work! The lighter is isolated from the rest of the circuit and the battery will run down. You need a standby maintenance charger [Sears offers several] wired across the battery that tapers the charge as needed and an extension [you fabricate] that brings the connection out through the front grill. Juat plug the beast in when you pull into the garage and "no sweat", if you need to leave the car at the airport, do what the manual says and disconnect the battery, [or use a cut off switch on the positive terminal] Sorry, all your stereo preset are Kaput! Or then plug in a 9 volt battery to cigaret adapter into the cigaret lighter to preserve your stereo settings,

sorry Mike, my J30 battery doesn't run down after a few days....
I would love to know where it says that in the manual, can you give me a page number?
You must have a parasitic battery drain....

http://www.aa1car.com/library/battery_runs_down.htm

My mistake! I have a bad habit of speed reading. On page 7-14 of the 1997 J30 owners manual the correct reading is "If the vehicle in not to be used for 30 days or longer, disconnect the " - " negative battery terminal cable to prevent discharge." And to boot I did have my original stereo unit replaced under warranty for an internal sneak path to ground. In any case I did take the precaution of installing a maintainer battery charger. Belt and suspenders reaction.

Apologies to all that I have misled!