It's easy to check tightness of the alternator belt first. It may be slipping. Do not over tighten as you risk damaging water pump bearings. Also check connections while you are there, ground, and so on. 

Chris.

Wysłane z iPhone'a

Dnia Jan 20, 2012 o godz. 0:36 Peter Kote <pkote@YAHOO.COM> napisał(a):

> I am on a roadtrip to Belize and have a National Luna unit.  I have two brand new batteries (41) and have the unit plugged in all day to the 12 volt system.  While driving i seem to loose some juice.  This morning the battery read 13.2 and at the end of the day it read 12.7.  Does this mean my alternator maybe not be working efficiently? it is the original altenator on a Westy 90 with 110,000 miles.
>  
> any feedback would be appreciated - thanks.
> pete
>  
>