By eats alternators means what? What's the time interval. How do you know it's an alternator? Bearing noise? Decoupler rattle? What is the symptom?
Do you have a multimeter? Best to get one, if not. What output voltage are you getting generally?

With the limited information provided, I have to guess bad alternators. New? Remanufactured? Rebuilt? Boneyard?
I haven't had frequent alternator replacements on any vehicle, they are fairly long life machines. The one on my 2016 DGC is OE.

 

Yeah, that was a really bad description. Apologies for the incomplete description. The battery light comes on. Turn off the car and the car will start w3ith the light out. Then after 15 minutes, light comes back on. No unusual noises - ever. The light no longer comes on, but the battery voltage continues to reduce. (I eventually added a volt gauge plugged into the cigarette lighter). Once the battery goes under 1.5 V, of course it is no longer reliable. Replace the alternator and all is well for a few months. I just installed a new battery because the old one died (again). 2 years into a 3 year warranty at Wal Mart so ic did not cost us anything.

 

1. Is your van OEM stock configuration in terms of electrical equipment/accessories or does it have modifications?
2. Can we assume you have done a good visual inspection of the alternator wiring and adjacent connectors?
3. Are you installing NEW or Rebuilt or USED alternators?
4. If NEW, where are you buying them? Amazon chinesium?
5. Do you live in a coastal/high salt environment?
6. How many alternators have you gone through? one or two or is the number significantly higher?

 

It is a stock version. Always stored in an air conditioned/heated garage. We keep a 2003 Dodge Neon, 2010 Ford Explorer, 1993 Town and Country, and recently a 2015 Escalade ESV.
We have not located any chafed or otherwise damaged cabling or corrosion.
I have done both new and used. Sourced from retail auto parts houses (OReilly, AutoZone). Two instances ago was new/used from partsgeek.com. Most recent was new in a Chrysler box off EBay.
Middle Tennessee so not a lot of corrosion
We have purchased 6 alternators (probably #7 this time) Always install 3 year batteries from WalMart. I could possibly upgrade the battery? I am paying someone else to do the repair this time so it got a ride on a wrecker yesterday. ;-)

 

Keep in mind, the alternator output is actually controlled by the engine computer. Perhaps the computer is faulty and not all of the alternators.

I haven't replaced an alternator on any of my vehicles ever, including two 5th Gen T&Cs. One is at almost 180k miles, the other approaching 100k miles. They salt the roads here in the winter, too.

 

Keep in mind, the alternator output is actually controlled by the engine computer. Perhaps the computer is faulty and not all of the alternators.

I haven't replaced an alternator on any of my vehicles ever, including two 5th Gen T&Cs. One is at almost 180k miles, the other approaching 100k miles. They salt the roads here in the winter, too.

Perhaps the OP is continuously buying garbage Chinese alternators, but in my experience with electrical gremlins haunting my 2014, he needs expert diagnosis in lieu of a series of alternator rentals. In my case I had a bad PCM, which was replaced under the 8/80 emissions warranty. There were over 30 stored DTCs...none of which could be accessed by a simple OBD2 scanner.

Something else is amiss here. Might be worth the dealer diagnostic fee to identify the problem and fix it once.

I also had a bad alternator. I ponied up a few extra bucks for a Nippondenso reman unit...which is still happily humming along today.

 

I'll add one seemingly random follow-up question. Do you regularly power wash your engine compartment?

The reason I ask is I know someone who had, what seemed like the incredible misfortune of burning through ignition control modules on a vehicle (not a Chrysler minivan, but the example is still worth noting). What finally came out in the end is that the owner (not me if anyone had the idea) had a penchant for periodically power washing his engine compartment and, not surprisingly, the engine-mounted ignition control modules did get hit with water. The owner's assumption was that the control module must be waterproof - it wasn't. He stopped power washing his engine and magically the ignition control module issue went away.

My other idea(s) might include investigating the alternator mounts/grounding points for corrosion as well as the battery connections. If this isn't an engine control module issue, I still keep going back to a wiring/harness issue. Having that many bad alternators is not very probable.

 

check for oil leaking on the front of the engine above the alternator. most likely valvecover, but timing cover is known to leak after a bit as well.

I had the OEM alt rebuilt and the builder opened it up and tapped out a bunch of coked up oil on the stator/brush cover. He said fix your oil leak or you'll be here again next year. I didn't get to resealing the engine for a bit but by that time i had to get another new alternator.

COINCIDENTALLY on just yesterday i bought a v6 Durango to replace our van. I used this exactly same story to justify another $500 price break due to evidence of leaking right about the alternator.