Chassis Batteries won't charge while driving

[dano]

I have new chassis batteries.  Why do they charge up when plugged in shore power but, after driving for an hour and stop the rv, it won't start?  So I plug her in over night and voila! full charge. 

[ibdilbert01]

Sounds like your alternator might be faulty.

[DaveVA78Chieftain]

Winnebago only posts online wiring documentation back to 1990.  Try contacting Winnebago to see if they can provide 1988 wiring diagrams.  Not sure if you have cables reversed or what.  Can you take any pictures of your setup and post them?

Dave

[dano]

But my altenator is only 3 years old.Thanks for you response

[piorun]

Check voltage at a alternator with engine running. It should be 13.8v.

[dano]

Thank you! And yes it was my alternator, voltage going in but not out, could be that my regulator inside is fried. Now looking for 120 amps altenator. But I can't seem to find the part number on the alternator.  Hm?
Thanks again.

[DaveVA78Chieftain]

Being a 120 amp alternator does yours have the wide 6 rib belt rather than a narrow V-Belt? If so,

NAPA (http://www.napaonline.com/Catalog/Result.aspx?Ne=600426&Ntk=Keyword&Nty=1&Ntt=&N=599001+101988+50014+2014076+29580+4014038+5999999+4290225309)
2134626G - Standard
134626G - Premium
AL8688X - Bosch

Autozone (http://www.autozone.com/autozone/parts/1988-Chevrolet-P30-Van/Alternator/_/N-jcrkhZ9ridy)
DL1491-6-4 - Duralast
1491-6-4 - Valuecraft

Dave