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Message-ID: <001e01c513fa$207c83b0$8ad6ecdc@george>
From: "George Lendich" <lendich@optusnet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-740841@logan.com>
Subject: Re: [FlyRotary] Battery voltage (was: Racetech RV6A Forced Landing)
Date: Wed, 16 Feb 2005 17:11:51 +1000
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Bill,
What would you expect the battery to show under starting load.
George ( down under)

>
> >  I suspected a charging system failure immediately and checked the
> >battery voltage in the SDS monitor. This read 9.5 volts so I knew then
that
> >we had a charging system failure. At the time, I was not worried about
> >making it to an airport, assuming that the alternator had failed just in
the
> >last few minutes and believing that I had 20-25 minutes of battery power
> >remaining. In fact, it is likely that the alternator failed soon after
> >takeoff from Springbank but I did not notice signs of the failure until
the
> >battery was well over half dead.
>
>          At 10.5 volts, the battery is officially 100% discharged. At 9.5
> volts, the battery was not "half dead" but completely dead. He was running
> on the battery "fumes".
>
>          The battery voltage drops very, very rapidly under 11 volts.
>
>          If the battery voltage drops much below 13 volts while in flight,
> an idiot light should come on, and you should head for the closest
airport.
> You should turn off anything electrical that you don't really need to fly
> the airplane, communicate, and navigate. A full-throttle climb might be a
> good idea if you are at low altitude and far from the nearest airport.
>
>          If the voltage drops below 12 volts, you should turn off
> everything electrical but the systems absolutely essential to keep the
> engine running.
>
>          At 11 volts, you need to pick a place to land and do it.
>
>          During and very shortly after starting, it would not be unusual
> for the battery voltage to dip below 12 volts. However, I would not take
> off with the system below 13 volts. Checking the battery voltage should be
> on the run-up checklist. For an EFI or EI engine, the battery voltage
> indicator should be as prominent and visible on the instrument panel as
the
> oil pressure indicator.
>
>
>
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