It IS possible that the battery just needs to be charged.

The battery may have been depleted to the point of not being sufficient to
close the master relay after your successful "jump start". (The relay coil
is powered by the battery) In this case, your battery would have been
disconnected from the alternator during the last flight, and would not have
received a charge.

Many Pipers (my Seneca is one) have an "Alternator-Source Power relay
energizing circuit" (a diode in series with a resistor), which allows the
alternator to close the master relay after a jump start, enebling the
battery to be recharged . I don't know about Mooneys . HTH


"Jon Kraus" wrote in message
. ..
Tell me what you think about this issue:
I flew 4443H ('79 Mooney 201) Saturday morning for a couple of hours.
One time during the flight, for about 5 minutes the High / Low voltage
light was flickering. It did stop flickering, the ammeter wasn't showing
a discharge, and the battery voltage remained above 13 volts so I didn't
worry about it. My partner then took it for a couple hour flight. At his
destination he forgot to turn the master off so when he returned he
needed to get a jump. He got it started, took off, was flying home, and
after 30 minutes or so lost all electrical power. He made it home and
after a manual gear extension landed without incident.

Alernator History:
The alternator was rebuilt 800 hours ago (2001)
I am unsure about the voltage regulator
New battery (GIL 35) 7 months ago

Is it possible that the battery just needs to be charged (low on water
maybe? I know probably not) or does it sound like the alternator /
voltage regulator has headed south? Maybe a set of alternator brushes
would cure the issue?

If we need to get a rebuild done can I get some recommendations for
shops (prices?) Also do you usually replace the voltage regulator at
this time too?

Any info or experiences would be appreciated. Thanks!!

Jon Kraus
PP-ASEL-IA