3rd alternator in 7 months
 

I have a 03 6.0 king ranch crew cab 4x4. This summer I replaced the stock turbo with a new Powermax, 2 days later the alternator quit. Since then I have replaced it a total of 3 times. I was told the batteries must be charged 100%. I charged them all weekend on a 2 amp charger. Any suggestions?

Have you had your batteries tested.

I just lost a set of batteries. My experience went well, since I knew what to do about it.

My first symptom was low charging voltage. It hardly ever went up to 13.8. It would vary while driving on the freeway from 13.2-13.6, only rarely getting to 13.8.

I suspected bad batteries, so I disconnected the batteries and charged them both for at least 4 hours each; my charger flagged a fault on both of them. I then took them to AutoZone. They initially measured just over 12.5 volts, before load testing. Load testing indicated they were putting out only 85% of what the battery was capable of new.
AutoZone replaced them for free, since they were 6 days less than 36 months old.

If you batteries don't test bad, you've probably got something going on with your wiring.

No I haven't had them tested. I will take them to the local Car Quest store, they have a tester that will charge and test them. I have been told batteries made today are constructed of a different material than the ones of old' and they need to be charged in a different way. He said to charge them all weekend @ 2 amps, Next is to take them into town and have them tested. I don't have a volt meter on the truck, but I have a Fluke, so I will test it in the morning. It used to be 14 to 14.7 volts, does that still hold true?
I am a retired auto mechanic, and I sure remember BUSTEDKNUCKELS lol

I see I failed to say what my voltage went to with new batteries; sorry about that.
It now goes to between 14.05 and 14.2 after the glow plugs turn off, and with no accessories on, which is about a minute after it fires up. Of coarse, this is the alternator pulling it there.
Each of my new batteries measures 13.05 volts while disconnected and after sitting overnight on the charger.

I took my batteries to the auto parts and they tested 35% on one and 65% on the other. The alternator is charging 14.7 volts. They only had one battery on hand, so I will pick up a set monday. Thanks for your help BUSTEDKNUCKLES

No problem tenwheel,

I'm glad to offer my help...it's just payback for all the help I've received on this forum.