"Jon Carlson" wrote in message news:
I have a Fujitsu Stylistic LT P-600, and the lighter adapter it came
with will accept 28V input (or 12V input). You may want to check the
default one for the C-500 to see whether it'll work as is.

The Auto/Air adapter that Fujitsu offers for the C-500 & P-600 is the
same part (FPCAA02) and is only rated for 12-16V input according to
their specifications. I'd be curious to know what part number your
adapter is, and what specs might be printed on it, because their
website definitely suggests they don't support 28V in.

Thanks for your time!
greg