wrote:
Robert M. Gary wrote:
: I have a 70amp alternator in my Mooney. I find that when I turn on
the
: landing light, the voltage drops down to around 13.0 volts or less.
: During off the landing light brings it back to 14.5 volts. The
Mooney
: Factory Service Center is telling me this is normal. They said
Mooney
: didn't design the plane to fly around under the continuous load of
the
: landing light.

: Opinions??

That isn't unusual to have reduced voltage output under load at low
RPM.
What RPM brings it back up to 14v or so?

snip

Excellent point. The original post is kind of lean on details. If
this is happening at idle RPM, it's perfectly normal. If it's
happening at cruise RPM I'd be a little concerned that the landing
light is dragging the bus voltage down so much. That is, unless the OP
forgot to mention that his "landing light" is actually 3 - 5 lights
spread across the wings and nose :-)

John Galban=====N4BQ (PA28-180)