Today's Message Index:
----------------------
1. 07:20 AM - Re: Charging the Aux Battery (Carlos Trigo)
2. 08:34 AM - Re: Charging the Aux Battery (Robert L. Nuckolls, III)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Charging the Aux Battery |
Thanks Bob
So you confirm that on Dual battery, One main Alternator and an Aux
alternator, with no cross-feed contactor, the Aux battery contactor must be
closed during normal operations otherwise the Aux Battery will not be
charged.
Then, what's the advantage of having 2 batteries?
Only to have more electron juice available?
Carlos
-----Mensagem original-----
De: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] Em nome de Robert L.
Nuckolls, III
Enviada: 30 de setembro de 2013 01:51
Para: aeroelectric-list@matronics.com
Assunto: Re: AeroElectric-List: Charging the Aux Battery
--> <nuckolls.bob@aeroelectric.com>
At 01:46 PM 9/29/2013, you wrote:
>--> <trigo@mail.telepac.pt>
>
>Bob and all
>
>This is probably a dumb question but I will make it anyway.
>In a Dual battery electric system architecture, like Z-14 for example,
>the Aux Battery will not be charging in flight unless the aux batt.
>Switch is flipped On (thus closing the Aux Batt contactor), right?
>
>Carlos
Z-14 is dual battery/dual alternator, split-bus
system. The aux battery is maintained by its
dedicated alternator.
In Z-14, normal ops are conducted with everything
ON except the cross-feed contactor.
On other dual battery systems with only one alternator
and perhaps an aux alternator, then both battery
contactors are closed during normal operations to
be charged in parallel.
Bob . . .
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Charging the Aux Battery |
At 09:22 AM 9/30/2013, you wrote:
Thanks Bob
So you confirm that on Dual battery, One main Alternator and an Aux
alternator, with no cross-feed contactor, the Aux battery contactor must be
closed during normal operations otherwise the Aux Battery will not be
charged.
Then, what's the advantage of having 2 batteries?
Only to have more electron juice available?
Essentially, yes . . . but capable of being
partitioned into separate tasks should the
alternator fail.
During alternator outage, an Aux battery might
be assigned the task of supporting an electrically
dependent engine while the main battery would
perhaps support an e-bus.
This isn't just about storing 'more juice' . . .
it's about selecting, crafting and operating
an architecture that offers the most favorable
failure modes effects analysis. FMEA is a
simple exercised of looking at EVERY part
of your electrical system and asking the
questions that drive your decisions toward
a more FAILURE TOLERANT design.
I'll suggest you review these two pieces
found on our website . . .
http://tinyurl.com/kzfgtpt
http://tinyurl.com/lpvth8d
The answer to your question about dual batteries
is broader than to explain their function.
The question you need to answer first is
"why would I think of having two batteries
and how would they participate in a aerial dance
contest where one or more of the contestants are
throwing in the towel."
This isn't about seeing the most reliable parts . . .
it's about building the most reliable SYSTEM
wherein absolute reliability of parts doesn't
drive risk. It is much less expensive to design
for failure tolerance than to buy only
components with established reliability
studies.
My personal design goal for aircraft is to
deprive any single failure of forcing me
to break a sweat in the cockpit. Given
a set of hardware limits and mission goals
for the airplane, then the pieces need to
be assembled in such a way as to minimize
risk.
Many of our brothers add 'backup batteries'
as a salve for their apprehensions about
lost of some really handy gadget on the
panel . . . without consideration of the
BIG PICTURE. My own apprehensions are best assuaged
by the notion that even if my airplane's
capabilities degrade to little better than
a J-3, as long as the wings stay on, the
engine keeps running and the flight controls
are hooked up, I have a well understood
opportunity to complete the flight comfortably.
I've flown rented A-36 Bonanzas with LOTS of
goodies on the panel without the slightest
concern about the maintenance records for any
particular appliance. This is because I fly
with these things in my flight bag.
http://tinyurl.com/d5mrjgh
With fresh batteries installed before departure
http://tinyurl.com/kjuhl67
Whether the salve for your apprehensions includes
a second battery is a decision you need to
answer by asking a LOT of other questions with
simple answers that illustrate predictable consequences.
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|