[jswente]

My 03 6.0 is eating up batteries like there's no tomorrow. Advanced has replaced 4 of them under warranty in the last 9 months. Its not killing cells, it will be fine then one day it will start cranking slow and two days later i'm getting jumped, take it to advanced and it says "replace battery" on the tester. I'm smart enough to know that its really not the battery that's bad its somethings causing them to go bad. But what? My dad mentioned that it could be boiling the water off if the voltage regulator is bad but the alternator is only 6 months old. It does seems like it is charging high though. Watching my voltage on my edge it never gets below 13.8 even at an idle. But never exceeds 14.2, i've read some threads where guys talk about voltages of 14.5 so i'm stumped. Any help would be appreciated.

 

[juniorssrollin]

I see 13.5-13.9 on my CTS with a 240 amp Alt.
Take alternator to an electrical shop and have them go thru it. Shouldn't be much money. Check your grounds.

2005 F350 CCLB FX4

 

[6.0newb!]

id get the alternator tested. and a +1 on checking grounds

 

[john galt]

I had a wire get corroded once, smaller wire on pass side battery.
It LOOKED fine but the wires into the connection were corroded and it would drop voltage and only on occasion.
got a new connector cut off the old one and cleaned up the wire a bit and no more problem.
I had all the symptoms you are describing including showing a high charge rate.
Plus as I said it was intermittent so it was kind of a PITA to find.

if everything "normal" checks out...

not sure if this helps but... :dunno: