> 
> David C. comments that:
> 
> >initially; states that: the green LED functions at 12.5 volts and above;
> >the yellow below 12.5 volts and the red between 12.5 volts and 12 volts.
> >So both Harmon and Derek are right: a battery below 12 volts is in danger
> >of not being able to start the car, still it seems that 12.5 and above is
> >sufficient and perhaps a little less would be ok...DC
> 
> Thanks for the clarification;  would it be reasonable then, that if a
> battery (primary, or otherwise) appeared to be in good shape, had its
> plates covered, had clean solid connections and was fully charged to 13+V,
> yet dropped to, say, 12V after hooking up to the starter or fridge, is due
> for replacement?  The assumption is that the charging system is also
> functioning correctly, btw.  
> 
    A battery that only reads 12v is junk. If it doesn't read a minimum 
of 12.5, forget it, IMHO. Actually, most battery texts agree, that I've 
ever seen. And having lived off grid for about 17 years of my life, 
using, maintaining, and even repairing batterys , I've read every thing I 
could find about batterys and how they function. And contrary to what was 
posted here earlier, a "good" battery stays at 13.5 and not just after 
it's charged briefly. Under load it might go lower, butshould spring 
right back after the load is taken back off.