REFLECTOR: Odyssey Battery

Chuck Jensen cjensen at dts9000.com
Fri May 11 16:29:43 CDT 2007


Hiroo,

Your not missing anything as far as the range of the Velo is concerned,
but its not always as simple as "land at the nearest IFR airport".
Every year or two, and some times more than once a year, the whole
Atlantic Seaboard (thanks to spell check, I didn't post Seabroad) will
be socked in with low lying fog that may be LIFR or worse.  3 or 4 years
ago, there was this very situation that trapped 3 planes that finally
ran out of fuel looking for someplace they could land.

Yes, you could head west over the mountains (Knoxville TN will be clear)
but it takes a brave heart to head for the mountains when the alternator
is TU and the battery is headed the same direction.  A couple hundred
miles to the south, or north, you might be in the clear, but the pucker
factor will certainly be high until you get there.  Now, if you know you
have 3 or 4 hours of battery and fuel to match, it becomes only a source
of concern, not of fright.  If I recall correctly, we fly our planes for
pleasure, not to scare ourselves half to death.

If I run the VFR capacity check and, with load shedding, I don't do
better than 2 hours, the PC 680 is out and the PC 925 is "coming home to
momma."  With that said, I expect the 680 will give me more than two
hours with load shedding--strobe and nav lights are the first to go.  If
things really get desparate, I might even consider killing the DVD and
XM radio, but let's not get hasty and panicky just yet.

Chuck Jensen




-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Hiroo Umeno
Sent: Friday, May 11, 2007 3:55 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Odyssey Battery


I don't have IFR experience yet so I might be missing something but...

Why do you need 2 hours?  Unless you are over open water or in the
wilderness of Alaska, you are never too far from an airfield with an IFR
approach, right?  So, if your "Low Voltage" light or "Alternater
Failure" light comes on, then the process should be...

1.  Declare emergency to whomever you are currently talking to... 2.
Get vectors to the nearest airfield with IFR approach... 3.  Get
yourself down.

With an average speed of a Velocity at 160Kts or more, you should be
able to get down under most situation in 30 minutes or less, no?

On my plane, I installed a secondary battery (motorcycle kind) that
kicks in when the mains go flat.  So the sequence of event on mine would
look like...

1.  Alternator failure light comes on. (Annunciator Panel) - Alternator
is no longer supplying 13.5V or above to the bus. 2.  Low Voltage
warning. (EFIS Alert) - Main battery getting low. 3.  Standby battery
kicks in (Annunciator indicates Backup Battery) - Main bus is isolated.
EFIS, panel lighting and Radios getting power 4.  Everything goes dark.

I am hoping this is enough warning to "get me down in a hurry".

The only thing about the way I did the electrical is that once the main
bus isolation kicks in, I will lose the ability to use any of the
external lighting (NAV, Strobe, Landing Lights, etc).

I will need to find a lighted field to land in.

Hiroo

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Chuck Jensen
Sent: Friday, May 11, 2007 12:11 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Odyssey Battery

Larry,

Good advice all.  Fortunately, the GRT EFIS provides for alarming
multiple voltage points, so an alternator going off line will put an
alarm on the screen and I have a flashing red light for a separate
alarm, though it doesn't put out an audio alarm to the head sets.  One
would hope that 2 hours is sufficient to escape IFR and with prompt load
shedding, perhaps 3 or more.  Still, juice is like money...more is
always better.

Chuck Jensen

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Laurence Coen
Sent: Friday, May 11, 2007 2:57 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Odyssey Battery


Chuck,

I use the Optima D34 (deep discharge version) like Pat.  I also did a
battery rundown test to check the real world expectation as opposed to
the theoretical.  During simulated night flight, two hours is all I got
if I

didn't shed load.  When the buss voltage hits 10V, your radios stop
working. In IFR this is not good.  The battery isn't really "dead" but
you are a no radio flight.  The unfortunate truth about alternator
failure is that it's noticed when the radios go dead. Too late!  The
other thing that often happens is that the alternator partially fails
and the battery slowly discharges with each flight.  This means when the
alternator finally gives up the ghost your battery is already dead.
What I'm trying to say is keep the volt and ammeter in your scan and
understand what they're telling you. If you suspect a problem, shed load
as much and as fast as you can. whatever is gone isn't coming back.

Larry Coen
N136LC

----- Original Message -----
From: "Chuck Jensen" <cjensen at dts9000.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Wednesday, May 09, 2007 1:23 AM
Subject: Re: REFLECTOR: Odyssey Battery


> Keith,
>
> I concur with the two different missions for the battery, though I 
> understand the PC 680, in good condition, should be adequate for both 
> missions; namely cranking an IO 540 as well as provide escape time 
> from IFR electrical failure.  The IFR escape capacity of the battery 
> holds importance to me.  The PC 680, in good condition, seems to have 
> the 17 AH seems adequate to "get home" if the electrons stop birthing 
> and several parties report the 680 CA is amply to spin the IO 540, so 
> I'm going to give it a go.
>
> My current FLA battery is getting to the point that even after a good 
> charging flight, the next day it just barely makes the start, though 
> it always has.  Of course, when I install the PC 680, if I still have 
> the same problem, then I'll know to look elsewhere.  I believe this 
> process is known as being a "parts replacer" rather than a mechanic. 
> Of course, being a parts replacer makes me qualified to work in most 
> any automotive shop these days!
>
> And Pat, looking at your 38# monster battery, I'm thinking if your 
> alternator goes out, that you'll just have to remember to fix it after

> two or three days of flying.  It's got enough juice to get you home, 
> back again and home again.
>
> Chuck Jensen
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
> On Behalf Of Keith Hallsten
> Sent: Tuesday, May 08, 2007 9:52 PM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: Re: REFLECTOR: Odyssey Battery
>
>
> Chuck,
>
> Sure - even a very small sealed lead-acid battery will crank the 
> engine... However, if you file IFR or fly at night and don't have a 
> back-up alternator you should consider establishing a minimum capacity

> for the battery that will be sufficient to get you to your intended 
> destination without breaking a sweat.  That's an entirely different 
> question and will depend on your enroute electrical loads for, say, 
> night flight.  If you stick to day VFR, this is not a significant 
> consideration unless you have an electrically dependant engine (EFI, 
> electrical fuel pump only).
>
> Keith
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
> On Behalf Of Chuck Jensen
> Sent: Tuesday, May 08, 2007 4:16 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: REFLECTOR: Odessey Battery
>
> Is the Odessey PC 680 battery sufficient to crank the IO-540?
>
> Chuck Jensen
>
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