autocheck batt on (nice icon) - 87 5kq

[GEORGE MILLS]

En route. Stopped at friend's with access. Hundred miles from home.
Onboard diagnostics (CC head) indicates over 17V. Turn on all
consumables and drops to about 14.5V but jumps around a bit,
occasionally up to 16V. Suspect VR of Alt. Autocheck seems to activate
at ~15.5V constant. Not a CIH that parts are available in present
locale. Will I fry anything at this voltage? Torential downpour here.
All kinds of ducks quacking around. Friend has an extra charged batt
of different size I can use as backup if I cut the alt. belt. I'll
stick around for a bit, but I want to get home before in need of the
lights.

Thanks very much for any info.

Geo