finn.lassen(at)verizon.ne
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 Posted: Thu Jan 23, 2025 8:55 am Post subject: Switch Schemes for Reliability |
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Going through posts here from 2020 forward.
Very disappointed in your reply here, Bob, considering you did an autopsy on a PC680 that Joe Gores sent you in 2016 and found that the battery failed open.
Finn
On 4/30/2024 8:06 PM, Robert L. Nuckolls, III wrote:
| Quote: | At 06:16 PM 4/20/2024, you wrote:
| Quote: | --> AeroElectric-List message posted by: "wsimpso1" <wsimpso1(at)comcast.net> (wsimpso1(at)comcast.net)
Recently I spotted a document from a well known brand of EFII recommending an “Essential Buss†backed up with a Aux Battery and simple switch to connect it. While this is supposed to make powering the engine possible even if the Main Battery Bus goes cold, |
Under what circumstances would your main battery
ever 'go cold'?
When maintained with century old practices
for system reliability, a battery can
be the most reliable source of energy in
the system. So finding yourself lacking in
battery supplied energy means you've lost
all engine driven sources, your battery
is inadequate to the task of meeting your
battery only endurance goals; -OR- your system
architecture/craftsmanship fails to eliminate
all single points of failure in energy
conduction pathways to accessories necessary
for comfortable completion of a flight.
Adding any sort of 'back up' battery to a
system only adds to the number of devices
that beg for $time$ to maintain airworthiness
for yet another commodity . . . a thing
that begins to degrade, be consumed the day you
installed it. Tires, drive belts, engine oil, propeller
blades, FUEL, etc are all things we fuss over
every flight as a matter of course . . . walk-around
during pre-flight is drilled into us from
day-one. But my flight instructor never said
a peep about batteries.
For as long as I can recall reading the
dark-n-stormy-night narratives in the aviation
rags, pilots who survived the dark-panel-syndrome
never once suggested that the battery in
their airplane was not properly evaluated,
maintained or utilized for comfortable
completion of flight under the circumstances
they experienced.
It's easy to debate 'reliability' at length
and with great enthusiasm. It's tempting
to pile on 'back-ups' at the risk of increasing
weight, cost of ownership and complexity of operation
. . . complexity that only work against 'aviate, navigate,
communicate' when things are not going well in the
cockpit.
I'll suggest a FOURTH feature in the famous
axiom for emergency management: 'First aviate,
then navigate, then communicate, but last and
certainly least, FIDDLE WITH STUFF ON THE PANEL'.
Having a battery 'go cold' is the final chapter
in a litany of failures that PRECEDE loss of the
the battery. Things over which we have absolute
control.
I've not forgotten about you guys. The new
crowbar OVM project is sitting on the bench
waiting for a window of opportunity amongst other
matters. Additionally, we need to spool up
the discussion on Figure Z-101. I'm increasingly
of the opinion that Z-101 should be the ONLY
z-figure in any 'upgrade' to the connection.
It has the opportunity of being the legos/
tinkertoy/modular plug-n-play system with options
that adress EVERY electrical system configuration
requirement from ultra-light to LA-IVP with all
the 'goodies'.
But we need a cogent, convincing narrative to
accompany Z-101 . . . a option/by/option
account of when, why and how any particular
feature should be considered.
>Recently I spotted a document from a well known brand of EFII
>recommending an Essential Bus backed up with a Aux Battery
>and simple switch to connect it.
Yeah, Klaus was of similar opinion when I met
him back in '86 . . . and in all years since. So
to have MOST producers of really slick electro-whizzies
in years since. It's really easy to suggest that
"adding back up to keep MY miracle product
powered and happy" is a good thing to do . . .
but I'll wager that few if any have brought
the forces of experience and thoughtful Failure
Mode Effects Analysis to bear on their recommendations.
The goal: craft and maintain a system with an
extremely high probability of bringing
you home without breaking a sweat. Every
failure is a maintenance even, not an
emergency.
Bob . . .
////
(o o)
===========o00o=(_)=o00o=========
< Go ahead, make my day . . . >
< show me where I'm wrong. >
=================================
In the interest of creative evolution
for the-best-we-know-how-to-do based
on physics and repeatable experiment.
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