Today's Message Index:
----------------------
1. 04:31 AM - Re: Power diode drops (LarryRobertHelming)
2. 06:43 AM - Re: Comm receiver overload (William Yamokoski)
3. 08:11 AM - Re: Main Bus Feed (Dan Checkoway)
4. 08:17 AM - Re: Re: AeroElectric-List Digest: 32 Msgs - 06/03/04 (Dan Checkoway)
5. 08:54 AM - Re: Re: AeroElectric-List Digest: 32 Msgs - 06/03/04 (BobsV35B@aol.com)
6. 08:57 AM - Use of iPod (BobsV35B@aol.com)
7. 10:08 AM - Re: Use of iPod (Tim Coldenhoff)
8. 10:25 AM - Re: B&C LR-3C question (James Foerster)
9. 10:46 AM - Re: Mr. Brain OT (Brian Lloyd)
10. 10:51 AM - Re: Re: Power Diode Drops (Brian Lloyd)
11. 12:44 PM - Re: Digital Music in the Cockpit (Brian Lloyd)
12. 01:09 PM - Re: Digital Music in the Cockpit (Brian Lloyd)
13. 01:11 PM - Re: Re: Power Diode Drops (Paul Messinger)
14. 01:16 PM - Re: Re: AeroElectric-List Digest: 32 Msgs - 06/03/04 (Brian Lloyd)
15. 01:20 PM - Re: Comm receiver overload (Brian Lloyd)
16. 01:41 PM - Re: Re: Power Diode Drops (Paul Messinger)
17. 02:17 PM - Fw: Re: Power Diode Schottky availability (Paul Messinger)
18. 02:47 PM - Fw: battery capacity remaining (Paul Messinger)
19. 02:51 PM - Fw: battery capacity remaining (Paul Messinger)
20. 02:57 PM - Re: Re: Power Diode Drops (Brian Lloyd)
21. 02:57 PM - Re: Power diode drops (Paul Messinger)
22. 03:06 PM - Re: Re: Power Diode Drops (Brian Lloyd)
23. 03:22 PM - Re: battery capacity remaining (Trampas)
24. 03:33 PM - Re: Re: Power Diode Drops (Paul Messinger)
25. 04:01 PM - Re: Re: Power Diode Drops (Paul Messinger)
26. 04:59 PM - LOAD DUMP TEST RESULTS #1 (Paul Messinger)
27. 05:28 PM - Re: Re: Power Diode Drops (bkuc1@tampabay.rr.com)
28. 07:37 PM - Re: battery capacity remaining (Brian Lloyd)
29. 08:15 PM - Re: Re: Power Diode Drops (Brian Lloyd)
30. 09:27 PM - Re: Re: Power Diode Drops (Paul Messinger)
31. 09:33 PM - Transponder not working (Steve & Denise)
Message 1
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| Subject: | Re: Power diode drops |
--> AeroElectric-List message posted by: "LarryRobertHelming" <lhelming@sigecom.net>
Please help educate those of us less gifted on the electronics. Paul, you
wrote in part below as follows:
"> Look at the minimum voltages required for some avionics and then look at
the
> Amp hours available in a battery with a 0.5V lower end of useful life
> voltage. 0.5 volts can be a significant increase in useful life, when you
> must run on battery power alone."
When using Nuckoll's wiring, I maybe wrong -- when running from the e-buss
with the alternate feed activated ( due to alternator failure for instance )
that the diode that normally is used to power the e-buss is bypassed and it
is no longer a factor and we do not need be concerned about the voltage
drop. I understand the Schottky power diode has less voltage drop, but does
that really matter since our alternators produce more than we really need
anyway?
Indiana Larry, RV7 TipUp "SunSeeker"
----- Original Message -----
From: "Paul Messinger" <paulm@olypen.com>
Subject: AeroElectric-List: Power diode drops
> --> AeroElectric-List message posted by: "Paul Messinger"
<paulm@olypen.com>
>
> Just ran some real tests. (Power supply in constant current mode. (TEK PS
> 2511 Programmable Power Supply), 'In calibration' for the curious :-)
>
> A "typical" Diode bridge (25A rated) V drop at 7 amps is 0.81V (0.76V at 2
> amps) and a Schottky power diode is 0.31V (0.25V at 2 amps), Both at room
> temp.
>
> The extra 0.5V (usable) you get (with Schottky) can be a lot of extra
> battery life.
>
> Look at the minimum voltages required for some avionics and then look at
the
> Amp hours available in a battery with a 0.5V lower end of useful life
> voltage. 0.5 volts can be a significant increase in useful life, when you
> must run on battery power alone.
>
> I am using a 160CMQ045 that is insulated from the case and has 3/16" (#10)
> boltable lugs. So while not inexpensive (just under $30 in ones), its very
> easy to mount and wire. Use www.findchips.com to locate stock.
> (Currently in stock at Digikey.)
>
> Useful for both "avionics bus" etc and also for charging a backup battery
> where the V drop of "normal" bridge diodes would prevent a full charge
(not
> to mention the heat sink required during a high current chargeing period.
>
> The secret to low V drop with Schottky diodes, besides the technology, is
a
> large die size IE high current rating. The above part is two diodes
> internally connected as a full wave rectifier rated at 160 amps each. Thus
> its very close to a drop in replacement for the diode bridge Electrically
> direct replacement and mechanically "no insulation" bolt down mounting.
>
> Plus nearly 2/3 fewer watts lost in heat you must sink.
>
> There are lots of other Schottky diodes available but few with as simple
> mechanical and electrical mounting.
>
> Paul
>
>
Message 2
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| Subject: | Re: Comm receiver overload |
--> AeroElectric-List message posted by: "William Yamokoski" <yamokosk@lakemichigancollege.edu>
Hi Brian,
Thanks for the response. I do have noise filters at both the radio and intercom
d-sub connectors, but you've given me other good thoughts to pursue.
The problem doesn't seem to be dependant on frequency or headset. In addition
to buying a new radio I re-wired the entire system using shielded wire whenever
possible and moving all communication wires as far away from other wires
as I could. This has only been vexing me for a year and a half now....I'm about
ready to throw the whole mess away and motor on happily just using the handheld.
Anyway, thanks again for the input.
Bill Yamokoski
Message 3
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| Subject: | Re: Main Bus Feed |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
This is just a shot in the dark from a newbie, but why not tap your main bus
feed into the #2 wire just aft of the firewall? Sort of a "tee" junction.
I don't know what type of hardware would work best for that (i.e. some big
robust guarded "terminal strip" type of thing?). I'm sure Bob or one of the
other guys will chime in with a hardware pointer if this suggestion is
valid.
This way, you avoid the "lose your main bus in the event of a FWF fire"
issue, you probably can use the shortest possible run & smallest gauge, etc.
Let me know if I'm on crack, and good luck.
)_( Dan
RV-7 N714D
http://www.rvproject.com
----- Original Message -----
From: "Jim Stone" <jrstone@insightbb.com>
Subject: AeroElectric-List: Main Bus Feed
> --> AeroElectric-List message posted by: "Jim Stone"
<jrstone@insightbb.com>
>
> Hi Guys,
> I'm building a Harmon Rocket II and have two 17ah batts in the baggage
compartment each with their own battery contactor. From the contactor, I
ran #2 wire fwd thru the firewall, some ten feet or so, to the starter
contactor.
> My Main and Endurance busses will be located on the cockpit side of the FW
which is a very short distance from the starter contactor and main battery
wire.
>
> Question 1: Would it be better to home run another large wire (#4 or 6
awg) from the battery contactor as shown in dwg 11 to the main bus, or pick
up the shortest route, directly from the starter contactor (hot side of
course), using a much smaller wire (8 awg or so). The main potential
problem with connecting to the starter contactor is it is on the engine side
of the FW and in the event of a fire, I would loose my feed to the Main bus
as the wire burns. By the way, the main batt wires both + and - run thru a
stainless steel handrail 90 deg fitting on the FW so there is no bolt thru
the FW for the + battery lead.
> Question 2: If I go with the home run method, do you recommend using a
different route for the wire within the aircraft or run it along side the #2
+and- wires?
>
> Thanks,
>
>
Message 4
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| Subject: | Re: AeroElectric-List Digest: 32 Msgs - 06/03/04 |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
> I think I like the idea of having a lot of music on one device but I can't
> see me sitting for hours loading this thing full of music--or is there a
> better way? How much time do you have putting your entire collection on
> your iPod? Also is there a good website for picking out one of these
> devices? I have tried a search for this but end up running in circles.
You manage everything in software. The iTunes app lets you organize your
music. If you don't care about playlists, just drag all your MP3/WMA/etc.
files into your music library and be done with it.
When you connect the ipod to your PC, the thing *automatically* updates --
and will absorb any changes you made since the last time you connected it --
again, automatically.
The update process usually takes about 30 seconds, and you can do other
things while it happens. I use the firewire that came with the ipod. It
can also do USB. I presume both are roughly equivalent in speed. I think
the first time I connected it, and that first time iTunes had to load 2800
songs onto the ipod, it took about 20 minutes or so. That's a one-time hit
that you never have to endure again, doing incremental updates of songs
you've added, removed, moved, etc.
Regardless of custom playlists, the ipod sorts everything for you
automatically by artist, album, song name, genre, etc. Usually when I hit
play on the ipod, I'm navigating to a particular album that I want to hear.
I only use playlists on occasion.
Anyway, all this info is probably on Apple's site. I hate sounding like I'm
doing a sales pitch...
do not archive
)_( Dan
Message 5
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| Subject: | Re: AeroElectric-List Digest: 32 Msgs - 06/03/04 |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 6/5/04 10:19:16 AM Central Daylight Time,
dan@rvproject.com writes:
The update process usually takes about 30 seconds, and you can do other
things while it happens. I use the firewire that came with the ipod. It
can also do USB. I presume both are roughly equivalent in speed. I think
the first time I connected it, and that first time iTunes had to load 2800
songs onto the ipod, it took about 20 minutes or so. That's a one-time hit
that you never have to endure again, doing incremental updates of songs
you've added, removed, moved, etc.
Regardless of custom playlists, the ipod sorts everything for you
automatically by artist, album, song name, genre, etc. Usually when I hit
play on the ipod, I'm navigating to a particular album that I want to hear.
I only use playlists on occasion.
Anyway, all this info is probably on Apple's site. I hate sounding like I'm
doing a sales pitch...
Good Morning Dan,
I know I am coming into this conversation late, but isn't the iPod
restricted to use at a maximum altitude of ten thousand feet? I have heard tales
of
them crashing, in fact, destroying themselves in even very light turbulence
when at higher altitudes.
Any knowledge or experience along that line?
Long range flights are the ones where I would most like to have music, but
they are generally flown at fifteen to eighteen thousand feet. The iPod would
appear to be useless for those flights.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 6
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--> AeroElectric-List message posted by: BobsV35B@aol.com
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 6/5/04 10:19:16 AM Central Daylight Time,
dan@rvproject.com writes:
The update process usually takes about 30 seconds, and you can do other
things while it happens. I use the firewire that came with the ipod. It
can also do USB. I presume both are roughly equivalent in speed. I think
the first time I connected it, and that first time iTunes had to load 2800
songs onto the ipod, it took about 20 minutes or so. That's a one-time hit
that you never have to endure again, doing incremental updates of songs
you've added, removed, moved, etc.
Regardless of custom playlists, the ipod sorts everything for you
automatically by artist, album, song name, genre, etc. Usually when I hit
play on the ipod, I'm navigating to a particular album that I want to hear.
I only use playlists on occasion.
Anyway, all this info is probably on Apple's site. I hate sounding like I'm
doing a sales pitch...
Good Morning Dan,
I know I am coming into this conversation late, but isn't the iPod
restricted to use at a maximum altitude of ten thousand feet? I have heard
tales of
them crashing, in fact, destroying themselves in even very light turbulence
when at higher altitudes.
Any knowledge or experience along that line?
Long range flights are the ones where I would most like to have music, but
they are generally flown at fifteen to eighteen thousand feet. The iPod
would
appear to be useless for those flights.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 7
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--> AeroElectric-List message posted by: Tim Coldenhoff <rv9a_000@deru.com>
> I know I am coming into this conversation late, but isn't the iPod
> restricted to use at a maximum altitude of ten thousand feet? I have heard
> tales of
> them crashing, in fact, destroying themselves in even very light turbulence
> when at higher altitudes.
> Any knowledge or experience along that line?
I don't know how susceptible the iPod in particular is to
damage from altitude or G-force spikes, however this is a
general danger to ANY computer or other device with a hard
disk drive in it or that have a certain types of display.
The biggest problem with hard drives is the clearance between
the spinning disk and the head that reads/writes the data.
A sharp G force spike (like a firm landing) might cause what
is known as a "head crash" which means the head contacts the
disk and destroys the drive.
Devices that use FLASH memory or other solid state memory do not
suffer this problem of course, and you can get portable MP3
players that hold just a handful of songs on flash. You would
just have to load up the songs you want instead of having your
entire collection available.
I have also heard of issues with certain types of monitors or
LCD type displays that has to do with the the device failing
at high altitudes, but I am not certain of the details. Possibly
the lower pressure causes some kind of "blowout" in the screen.
I have flown laptops up to 17,500' with no problems, but they are
shutdown for takeoff and landing to prevent disk failures.
--
Tim Coldenhoff
#90338 - Finishing!
http://rv9a.deru.com
Message 8
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| Subject: | RE: B&C LR-3C question |
--> AeroElectric-List message posted by: "James Foerster" <jmfpublic@comcast.net>
Marty asked:
<Would putting the resistor in the circuit (or the two 220 ohm resistors as
Bob suggests) stop the current leak to the point where there is no battery
drain when hangered?>
No, the drain would be shunted via resistors. However, in the hangar, the contactor
is off, and thus the regulator is powered down. That is the beauty of the
master switch, as commony wired.
Jim Foerster
Message 9
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| Subject: | Re: Mr. Brain OT |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Eric M. Jones wrote:
> --> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
> Will all those aeroelectric-listers who had the nickname "Mr. Brain" in
> school please raise their hands?
It is funny now but it was a stigma then. I solved the problem by starting to
play Pop Warner football in 5th grade and then on the 'C' team in high school.
I had to beat up a couple of bullies too.
I suffered a setback in seventh grade when I won the California State Science Fair
with a home-grown infrared guidance system in a robot ladybug. I used one
of my mom's stainless-steel mixing bowls as the mold for the fiberglass body
and it looked like a ladybug to me so I painted it red with black spots. The
lead-sulphide sensors were at the prime focus of a couple of cheap flashlight
reflectors which made up the eyes. The chassis was galvanized sheet steel I scavenged
from a construction site. I used telephone wire I scavenged from the
same construction site. The amplifiers were darlington pairs made with germanium
transistors because I could scavenge them from discarded circuit boards.
Wheels were from model airplanes and the transmission was having the shafts of
the motors carefully touch the circumference of the drive wheels. I scavenged
the motors from old toys. Everything was pop-riveted together. No judge would
ever accuse an adult of having built it so I gue
ss I got a lot of points for originality.
I never really did live down the fact that our 7th and 8th grade science teacher
recorded my interview with Vin Scully and then played it for every science class
in the school or that one channel of the circuit went out so my robot would
only go in circles on TV.
Fortunately, when I got into High School girls were interested in getting into
good schools so the jocks weren't the only ones with girls interested in them.
Remember: the geek shall inherit the Earth. If you don't believe it, conside Bill
Gates.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 10
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Paul Messinger wrote:
>>The point that your xpdr and comm will transmit with higher power is a
>> good one. Since you will directly connect your e-buss to the battery in the
>> case of alternator failure, the end-point voltage relative to diode drop is
>> a non-issue.
>
>
> Why would I need to do that. Its an extra switch possibly a CB and its a
> direct battery connection that needs to be special wiring etc.
Because the failure may be with your battery contactor and you need a second path
from the battery anyway.
> Use the right diode and there is no reason for such an extra switch. Also
> then one needs to remember its a direct connection to the battery and one
> more thing to be sure is off when shutting down.
I don't think you are playing enough "what if that breaks" games. You need to
point to each component in your electrical system and consider how it will break
and then what the result will be.
There need to be two completely separate paths from the battery to the e-buss so
that there is no single point of failure in your electrical system that will
take out your e-buss.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 11
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| Subject: | Re: Digital Music in the Cockpit |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
frequent flyer wrote:
> --> AeroElectric-List message posted by: frequent flyer <jdhcv@yahoo.com>
>
> Let me reveal my age and my lack of knowledge. just
> exactly what is an ipod? How does it differ from a PDA
> or a palm pilot? How do you transfer music to it?
An iPod is a specific device made by Apple Computer that stores a large quantity
of music in a pocket-sized box about the size of a pack of cigarettes but only
about half the thickness. They are available with different storage capacities
ranging from about 10 gigabytes (about 3000 songs) to 60 gigabytes (about
18000 songs). It is a huge jukebox that fits in your pocket. It has a built-in
rechargeable Li-ion battery that will last about 8-10 hours between recharges.
I know that by that time I am most likely going to be out of the airplane
and somewhere I can recharge my iPod.
A Palm Pilot is a kind of a Personal Digital Assistant (PDA), a small hand-held
computer that stores information to which you wish to have access all the time.
Some PDAs also store and play music and therefore overlap with the function
of the iPod and iPod-like devices but they don't usually have the massive amount
of storage that the iPod has.
For example, my 20 GB iPod currently has my entire CD library of about 150 CDs
stored in it and it is not quite half full. I use the space that is unused for
music storage as a backup for what I consider to be important documents from
my computer.
The iPod connects to your computer using either a "Firewire" or USB interface.
The wire is used to both transfer data and to charge the iPod's battery. Apple
provides a free program called "iTunes" that acts as a database for your music.
It downloads your music or computer files into your iPod.
> See, now you know about me.
Hopefully this is helpful to you.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 12
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| Subject: | Re: Digital Music in the Cockpit |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
richard@riley.net wrote:
> --> AeroElectric-List message posted by: richard@riley.net
>
> The IPOD hard disk tends to head crash above 10,000 feet with just a touch
> of turbulence. I found out the hard way
Ahh, good point. I hadn't considered that but since the heads ride on an air cushion,
altitude is an issue. I regularly fly in the mid-teens.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 13
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
You are right, I assumed that it was clear that I was not talking about what
Bob has come up with as a design that is driven to some extent by the hi
diode drop and the more common contactor that uses one amp current.
Thus both the contactor load as well as the unacceptable diode voltage drop
have contributed to the current suggested design. Without these issues to
consider other designs are available that are simpler and avoid extra pilot
actions.
However common sense dictates that in the case of an alternator failure
where you need reliable electrical power to continue, you divert to the
nearest safe airport and not over fly one or more just to get to your
original destination.
I have an auto conversion so the engine needs electrical power to run.
Thus two independent electrical power systems, with only one alternator, as
there is no reasonable way to add a second alternator in my case. However
either system will power the acft for over one hour with reserve so
immediate diversion is not technically required but in my mind foolish not
to do.
I do not like the concept of direct connection of both batteries during
normal ops as its a single point of failure and or more complexity than
needed. I do not like the idea of more than a simple battery disconnect.
Having several separate switches to isolate the battery is not needed with a
different design.
The alternator charges the main battery and bus in a normal manner. I have a
power Schottky diode connected over to the second battery that keeps it
charged and the diode selected has a forward drop so that battery can be
fully charged, something not possible with "normal diodes". I use different
'low hold power' contactors so contactor power is 100 ma or so and not a
significant concern.
While there are dual independent electrical systems for engine power there
is only one xponder for example. Thus the need for what used to be called
the avionics bus that is powered by either electrical system. This is the
second Schottky diode usage. With its low V drop there is no need for a
direct battery connection etc. Either battery can automatically provide
power and the low diode V drop provides 11V to the equipment all the way
down to near zero charge state.
Bob has in the past advocated keeping the pilots load to a minimum and I
agree. In my case any single electrical system failure is kept isolated to
that system and the only pilots action is to note the "its failed" light and
note the clock is counting down and hopefully there is a nice airport within
100 miles to get to.
Paul
----- Original Message -----
From: "Phil Birkelbach" <phil@petrasoft.net>
Subject: Re: AeroElectric-List: Re: Power Diode Drops
> --> AeroElectric-List message posted by: "Phil Birkelbach"
<phil@petrasoft.net>
>
> What kind of architecture are you talking about? If you plan to simply
> divert then it seems to me that you don't need the e-buss or the diode at
> all.
>
> Godspeed,
>
> Phil Birkelbach - Houston Texas
> RV-7 N727WB (Reserved) - Panel
> http://www.myrv7.com
Message 14
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| Subject: | Re: AeroElectric-List Digest: 32 Msgs - 06/03/04 |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Dave Ford wrote:
> I think I like the idea of having a lot of music on one device but I can't
> see me sitting for hours loading this thing full of music--or is there a
> better way? How much time do you have putting your entire collection on
> your iPod? Also is there a good website for picking out one of these
> devices? I have tried a search for this but end up running in circles.
If you using the Apple "iTunes" program you just feed your CDs into it when you
have time. I did it over about a week. Whenever I was using the computer I
would feed it a couple of CDs while I was working. The program "rips" the songs
from the CD (copies, compresses) and stores the music on your computer's hard
disk. Whenever you plug your iPod into the computer to recharge the iPod's
battery it automagically downloads the changes to its memory without you having
to do anything specific.
As for names of songs, albums, and such, the iTunes program automatically searches
an on-line database for album information so you don't need to type in all
the information about each album and song. After that you can construct your
own "playlists", selections of song groupings which will also get downloaded
to the iPod when you plug it in.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 15
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| Subject: | Re: Comm receiver overload |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
William Yamokoski wrote:
> --> AeroElectric-List message posted by: "William Yamokoski" <yamokosk@lakemichigancollege.edu>
>
> Hi Brian,
> Thanks for the response. I do have noise filters at both the radio and intercom
d-sub connectors, but you've given me other good thoughts to pursue.
> The problem doesn't seem to be dependant on frequency or headset. In addition
to buying a new radio I re-wired the entire system using shielded wire whenever
possible and moving all communication wires as far away from other wires
as I could. This has only been vexing me for a year and a half now....I'm
about ready to throw the whole mess away and motor on happily just using the
handheld.
> Anyway, thanks again for the input.
Make sure that the shield for your mic wiring is grounded only at your radio, intercom,
or audio panel. If you have a metal airplane make sure that the mic
jack is insulated from the airframe.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 16
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Perhaps my earlier reply on this subject was missed or passed in the night
:-)
I have NO single failure point in my electrical system design (which is
extremely different from what you may have been accustomed to on this list,
including some suggested auto systems) that will stop my engine which
requires electrical pwer to run.
I have two batteries and two sources of power to the avionics. If both fail
I have a glider as my engine is an auto conversion with NO MAGS. Each
battery can independently run the engine and necessary avionics with any
failure of the other independent system. The system also auto detects nearly
all failures and automatically switches to the back up system and then warns
the pilot. Not that uard to do either.
A simple switch that adds com to my NOW glider is of little help. If a
contactor fails I simply rely on the other battery/contactor.
As for doing an FEMA you do not know my background or you would never
question my qualifications on perfotrming far more complex designs than this
simple design effort. To me this is a dirt simple task compared to a
spacecraft that cannot be repaired in orbit and must survive many failures
and still perform its mission. The FMEA etc is in principle the same, just
much less complex.
This might be a good place to point out that reliability and failure rates
were NEVER used except in the preliminary design concept stage as the
numbers game is based on a large uniform population and a few failures are
on little concern. Our design requirements were to be 100% failure tolerant
and depending on the system perhaps 2 or 3 failure tolerant. This includes
wiring connectors etc etc etc etc. This design approach was flight proven
over and over again for tens of years.
My original point is there are better and or equally as good designs out
there and it seems that every person who suggests a different design is
pounced on as violating the standard approach.
No intent to be abrupt but I am a slow typest and frustrated at the amount
of time this seems to being taking from more important things.
I think I have addressed your below comments basically as you do not have my
design in mind.
Paul
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: AeroElectric-List: Re: Power Diode Drops
> Because the failure may be with your battery contactor and you need a
second path from the battery anyway.
>
> > Use the right diode and there is no reason for such an extra switch.
Also
> > then one needs to remember its a direct connection to the battery and
one
> > more thing to be sure is off when shutting down.
>
> I don't think you are playing enough "what if that breaks" games. You
need to point to each component in your electrical system and consider how
it will break and then what the result will be.
>
> There need to be two completely separate paths from the battery to the
e-buss so that there is no single point of failure in your electrical system
that will take out your e-buss.
Message 17
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| Subject: | Re: Power Diode Schottky availability |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Subject: Re: AeroElectric-List: Re: Power Diode Schottky availability
> Excerpted from Bob's reply to my post
>
> > The diode bridge rectifier was chosen because of its ease of
mounting
> > (has mounting hole, needs no electrical insulation from airframe)
and
> > ease of connection (fast-on terminals). The selection wasn't based
on
> > electrical performance . . . electrical performance was not
> > significant. This product was selected because it was inexpensive,
> > readily available from dozens of off-the-shelf sources, and easy to
> > mount. This device has a very high order probability of
> > successful implementation by the neophyte airplane builder. If there
> > were a Schottky based product available in the same package, it
would
> > indeed be more attractive
>
> My initial reply
>
> ""I have had the power schottky diode I am discussing for at least 5 years
> and
> it was not a new design then and in distributor stock at that time. So I
> disagree that good and easy to use parts were rare even 5 years ago and
more
> likely 10 years ago. It does take some time to see what is out there which
> is harder to do than going to RS and picking a part off the shelf.""
>
> I researched my time line and found the date code on my diodes is 1999.
>
> They are listed in the mfgrs data book printed in 1992 (the one I have
here
> on hand). Likely not a new product even then. The "identical package
> comment" makes no sense to me.
>
> Im my application electrical performance is very significant not ass Bob
> says "" The selection wasn't based on electrical performance . . .
> electrical performance was not significant. "" . But I have different
> design requirements than any found in the "Book" either then when I was
> designing or even today"
>
> This part needs NO insulation, has lugs for #10 SCREWS etc.
>
> There are many other parts suitable that either are insulated or require a
> Very simple mount with insulator kit both readliiy available.
>
> I would worry about flying in an aircraft that was owner wired and the
owner
> had lacked the skills to properly install such a device.
>
> As for availability, such an item could be added to the list of other non
RS
> parts at Aeroelectric or B & C.
>
> With all due respect to disagree.
>
> Paul
>
>
Message 18
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| Subject: | battery capacity remaining |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
----- Original Message -----
From: "Paul Messinger" <paulm@mtfind.com>
Subject: Re: AeroElectric-List: battery capacity remaining
> Its a very simple hardware task but different batteries do need different
> data tables to have accurate readings.
>
> You need current in/out and bat temp as well as battery characteristics.
All
> of the above is readily available, just waiting for the need. However with
> all the different batteries being used its a problem with matching to a
> specific battery
>
> Eventually I may build one for my acft.
>
> Paul
>
>
> > One thing I have not seen discussed here are battery energy remaining
> meters. These are devices that tell you how much energy is remaining in
the
> battery and how long the battery will battery will provide power at the
> current drain.
> >
> > These are common devices in boats, RVs, and people living on alternative
> energy systems (solar and wind power). Why not in aircraft?
> >
> > --
> > Brian Lloyd
>
Message 19
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| Subject: | battery capacity remaining |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
----- Original Message -----
From: "Paul Messinger" <paulm@olypen.com>
Subject: Fw: AeroElectric-List: battery capacity remaining
>
> ----- Original Message -----
> From: "Paul Messinger" <paulm@mtfind.com>
> To: <aeroelectric-list@matronics.com>
> Sent: Saturday, June 05, 2004 2:15 PM
> Subject: Re: AeroElectric-List: battery capacity remaining
>
>
> > Its a very simple hardware task but different batteries do need
different
> > data tables to have accurate readings.
> >
> > You need current in/out and bat temp as well as battery characteristics.
> All
> > of the above is readily available, just waiting for the need. However
with
> > all the different batteries being used its a problem with matching to a
> > specific battery
> >
> > Eventually I may build one for my acft.
> >
> > Paul
> >
> >
> > > One thing I have not seen discussed here are battery energy remaining
> > meters. These are devices that tell you how much energy is remaining in
> the
> > battery and how long the battery will battery will provide power at the
> > current drain.
> > >
> > > These are common devices in boats, RVs, and people living on
alternative
> > energy systems (solar and wind power). Why not in aircraft?
> > >
> > > --
> > > Brian Lloyd
> >
>
Message 20
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Paul Messinger wrote:
<lots of stuff deleted>
> My original point is there are better and or equally as good designs out
> there and it seems that every person who suggests a different design is
> pounced on as violating the standard approach.
I agree. I was making assumptions about your circuit topology. I apologize.
Your obvious understanding is the exception rather than the rule.
> No intent to be abrupt but I am a slow typest and frustrated at the amount
> of time this seems to being taking from more important things.
No problem. I responded without background information. It was in no way a comment
on your background or knowledge.
> I think I have addressed your below comments basically as you do not have my
> design in mind.
Right.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 21
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| Subject: | Re: Power diode drops |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
I covered this in another post. MY design is not anything you can find on
Bob's stuff as I have different requirements and thus no need for a switch
when the proper diode is used.
Paul
----- Original Message -----
From: "LarryRobertHelming" <lhelming@sigecom.net>
Subject: Re: AeroElectric-List: Power diode drops
> --> AeroElectric-List message posted by: "LarryRobertHelming"
<lhelming@sigecom.net>
>
> Please help educate those of us less gifted on the electronics. Paul, you
> wrote in part below as follows:
>
> "> Look at the minimum voltages required for some avionics and then look
at
> the
> > Amp hours available in a battery with a 0.5V lower end of useful life
> > voltage. 0.5 volts can be a significant increase in useful life, when
you
> > must run on battery power alone."
>
> When using Nuckoll's wiring, I maybe wrong -- when running from the e-buss
> with the alternate feed activated ( due to alternator failure for
instance )
> that the diode that normally is used to power the e-buss is bypassed and
it
> is no longer a factor and we do not need be concerned about the voltage
> drop. I understand the Schottky power diode has less voltage drop, but
does
> that really matter since our alternators produce more than we really need
> anyway?
>
> Indiana Larry, RV7 TipUp "SunSeeker"
>
>
> ----- Original Message -----
> From: "Paul Messinger" <paulm@olypen.com>
> To: <aeroelectric-list@matronics.com>
> Subject: AeroElectric-List: Power diode drops
>
>
> > --> AeroElectric-List message posted by: "Paul Messinger"
> <paulm@olypen.com>
> >
> > Just ran some real tests. (Power supply in constant current mode. (TEK
PS
> > 2511 Programmable Power Supply), 'In calibration' for the curious :-)
> >
> > A "typical" Diode bridge (25A rated) V drop at 7 amps is 0.81V (0.76V at
2
> > amps) and a Schottky power diode is 0.31V (0.25V at 2 amps), Both at
room
> > temp.
> >
> > The extra 0.5V (usable) you get (with Schottky) can be a lot of extra
> > battery life.
> >
> > Look at the minimum voltages required for some avionics and then look at
> the
> > Amp hours available in a battery with a 0.5V lower end of useful life
> > voltage. 0.5 volts can be a significant increase in useful life, when
you
> > must run on battery power alone.
> >
> > I am using a 160CMQ045 that is insulated from the case and has 3/16"
(#10)
> > boltable lugs. So while not inexpensive (just under $30 in ones), its
very
> > easy to mount and wire. Use www.findchips.com to locate stock.
> > (Currently in stock at Digikey.)
> >
> > Useful for both "avionics bus" etc and also for charging a backup
battery
> > where the V drop of "normal" bridge diodes would prevent a full charge
> (not
> > to mention the heat sink required during a high current chargeing
period.
> >
> > The secret to low V drop with Schottky diodes, besides the technology,
is
> a
> > large die size IE high current rating. The above part is two diodes
> > internally connected as a full wave rectifier rated at 160 amps each.
Thus
> > its very close to a drop in replacement for the diode bridge
Electrically
> > direct replacement and mechanically "no insulation" bolt down mounting.
> >
> > Plus nearly 2/3 fewer watts lost in heat you must sink.
> >
> > There are lots of other Schottky diodes available but few with as simple
> > mechanical and electrical mounting.
> >
> > Paul
> >
> >
>
>
Message 22
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Paul Messinger wrote:
> The alternator charges the main battery and bus in a normal manner. I have a
> power Schottky diode connected over to the second battery that keeps it
> charged and the diode selected has a forward drop so that battery can be
> fully charged, something not possible with "normal diodes". I use different
> 'low hold power' contactors so contactor power is 100 ma or so and not a
> significant concern.
Actually, the voltage settings for most aircraft alternator systems are incorrect
for most battery systems and even the 0.3V drop across the schottky diode will
ensure that your charging system will not properly charge your second battery.
The boat and RV (rolling land-yacht kind) markets have come up with a device called
a battery combiner. Basically it is a relay that closes to charge the house
and starting batteries together when the buss voltage rises to a point where
it is obvious that the alternator is on-line. When the alternator drops off
line and the voltage drops below 13V (26V), the relay opens and separates the
two batteries. This works only so long as both batteries are of identical types.
You can't mix flooded-cell, AGM, and gel-cell batteries if you want them
to last.
> While there are dual independent electrical systems for engine power there
> is only one xponder for example. Thus the need for what used to be called
> the avionics bus that is powered by either electrical system. This is the
> second Schottky diode usage. With its low V drop there is no need for a
> direct battery connection etc. Either battery can automatically provide
> power and the low diode V drop provides 11V to the equipment all the way
> down to near zero charge state.
I figured out that is what you are doing. I see where you are going and it makes
sense to me.
> Bob has in the past advocated keeping the pilots load to a minimum and I
> agree. In my case any single electrical system failure is kept isolated to
> that system and the only pilots action is to note the "its failed" light and
> note the clock is counting down and hopefully there is a nice airport within
> 100 miles to get to.
This is where something like an energy meter for the battery strikes me as a nice
thing to have.
BTW, my personal feeling is that I need to be able to complete my flight even if
I suffer an alternator failure. I have done a couple of Atlantic crossings
in my Comanche and may be as much as 6 hours from land so I need to make sure
I have enough "juice" to make it and still perform an instrument approach. I
have a dual-battery, single-alternator configuration in the Comanche. In my RV-4
I just made sure that the battery would carry the e-buss loads longer than
the fuel in the tanks would carry the airplane.
The electrical system in my Nanchang CJ6A will be very similar to the RV-4, i.e.
I will be able to power my e-buss longer than I will have fuel in the tank,
as I don't expect to do any hard-IFR flying in it.
I am going to explore the possibility with the FSDO of converting my Aztec to an
all-electric panel. That should be an enlightening experience. I once tried
to get the FSDO to give me an STC to put a 260 hp engine in my Comanche using
the exact same installation as in later model Comanches. Needless to say they
were far from helpful.
It all depends on what you are trying to accomplish.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 23
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| Subject: | battery capacity remaining |
--> AeroElectric-List message posted by: "Trampas" <tstern@nc.rr.com>
Brian,
Look at the Pulsar 200 Engine monitor. Using the hall effect current sensors
on the main battery wire and one on the alternator you can see how much
current is going into the battery, how much power is being used by plane and
how much power is remaining in battery. You can also monitor just about
anything else you want from canopy switches to battery temperatures.
Regards,
Trampas Stern
Stern Technologies
4321 Waterwheel Dr
Raleigh NC 27606
919-832-8441 Ext. 12 (voice)
919-832-8441 (fax)
www.sterntech.com
tstern@sterntech.com
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Brian
Lloyd
Subject: AeroElectric-List: battery capacity remaining
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
One thing I have not seen discussed here are battery energy remaining
meters. These are devices that tell you how much energy is remaining in the
battery and how long the battery will battery will provide power at the
current drain.
These are common devices in boats, RVs, and people living on alternative
energy systems (solar and wind power). Why not in aircraft?
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 24
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: AeroElectric-List: Re: Power Diode Drops
> --> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
> Paul Messinger wrote:
> > The alternator charges the main battery and bus in a normal manner. I
have a
> > power Schottky diode connected over to the second battery that keeps it
> > charged and the diode selected has a forward drop so that battery can be
> > fully charged, something not possible with "normal diodes". I use
different
> > 'low hold power' contactors so contactor power is 100 ma or so and not a
> > significant concern.
>
> Actually, the voltage settings for most aircraft alternator systems are
incorrect for most battery systems and even the 0.3V drop across the
schottky diode will ensure that your charging system will not properly
charge your second battery.
That has not been my experience on what I am using. Most regulators (that I
have inspected) are set somewhat high to get a rapid recharge. In any event
consider the following room temp info from Odyssey. But then each of us must
understand their aircraft needs and or fine some one who does.
The battery was discharged and then had a 5 ohm resistor placed across the
battery for 28 days. The battery was then charges at const V of 13.5V for 48
hours and achieved 97% of rated capacity.
13.5 plus 0.3V is 13.8V which is a commonly accepted minimum voltage for
charging. I have yet to see an alternator internal or external regulator not
set for at least 14.2V and most somewhat higher.
As my backup battery is not used for starting it starts each flight topped
off so the current from the alternator is not charging but used for the
backup engine systems some of which need to be always of for clean switching
over if needed. Both on is not requires for proper operation.
So my setup works well but others might not unless properly designed and
verified.
Paul
Message 25
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Its my mistake by not pointing out my application is different. I do think
however there are useful applications of some of my design.
As one gets older the mind is still fast but the mouth (fingers as
appropriate) is lagging behind and some conversations start in mid thought.
BTW having another PEER reviewer on this list is nice. Glad you are aboard.
Paul
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: AeroElectric-List: Re: Power Diode Drops
> --> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
> Paul Messinger wrote:
>
> <lots of stuff deleted>
> > My original point is there are better and or equally as good designs out
> > there and it seems that every person who suggests a different design is
> > pounced on as violating the standard approach.
>
> I agree. I was making assumptions about your circuit topology. I
apologize.
Message 26
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| Subject: | LOAD DUMP TEST RESULTS #1 |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Creating the report is a huge task, for the few who will take the time to
read it. This is a result of (in part) evaluation of every part of a mocked
up aircraft electrical system and some surprises were found. Most have
simple solutions.
The basic test setup system consists of an alternator, main bus, and battery
bus with associated contactors.
Fixed and variable loads and filter caps as well as the OPV module (defined
by Bob) was included in appropriate tests. Lots of digital and hi speed
analog scope PIX were taken as well as test conditions and results etc.
I do not believe in isolated analysis, as has been suggested "just look at
protecting the alternator from load dump damage". Turns out there were
several system level interactions that were evaluated as needing attention.
I must point out that alternator load dump protection turned out to be a
relative small part of the overall test series.
This is a quick report and the real report is much more detailed with lots
of graphics etc. as well as real data that could be duplicated if one were
interested. ALL tests were repeated several times over a period of several
weeks to among other things show test repeatability.
There are a couple of items that need further evaluation before all the
recommendations can be made.
Perhaps a review of the use of the alternator in autos vs. aircraft is
appropriate here.
In an automobile, the alternator is hard wired to the battery so cases of
load dump and or operation with no battery are not design requirements. Also
if something fails "pull over and call AAA". In an aircraft both the
alternator and battery can be internationally or accidentally disconnected
from each other and the electrical load. The internally regulated alternator
was not designed for this application and there are potential concerns as a
result.
I have completed load dump testing at 10, 20, 30, and 40 amps and that is
the limit of my electrical power to power the alternator (the lab lights
dim) . However the results show extrapolation is reasonable for 50 and 60
amp load dumps. Thus I see no concerns for those who wish to protect against
load dumps as large as 60 amps with the design margins on the solution
selected parts.
Other than transients, there is no effect on the main busses IF there is a
battery on line during the load dump. Transients are addressed in another
post.
For those who have the impression that a large CAP, say 25,000 mfd is
adequate if the battery is off line, well its not adequate as far as
suppression of load dumps with the alternator on and the battery off line.
There is again a simple solution however, more later.
Protection of the alternator if it has an external regulator is simple and
reliable. An internally regulated alternator is a different can of worms
however. If the alternator was taken off line when it was "in specification"
there is a simple solution to its load dump voltage spike. If the alternator
was taken off line because its regulated voltage was under control but
slightly high and the OVP circuit put it off line its still a simple fix.
However if the internal regulator failed short (full power/voltage out) or
went to a somewhat higher voltage then there is no simple solution as it
becomes a self excited high power heater. They have been known to literally
burn up into a mass of aluminum - copper mess and the belt is toast. Rare
but not unknown. More later on this.
As specific concerns and solutions are addressed in detail I will provide
specific parts and sources for these parts.
The report will include my silent (till then) partner who has, is, and will
be providing peer review. Peer review is critical to any design and I have
personally experienced its lack on occasion in the past as well as seen
others fail to benefit from such review. However its not easy to find a peer
and harder if we are not co-located. Thus email telecons etc delay and add
days (weeks?) to the report completion.
Paul
Message 27
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: bkuc1@tampabay.rr.com
From: bkuc1@tampabay.rr.com
Subject: Re: AeroElectric-List: Re: Power Diode Drops
If I can try to get this straight, the diode is there so not to feed e-bus to the
main bus when the alternator quits.
You would have master on during normal time, and when the alternator quits, you
would turn on the e-bus switch and turn off the master switch, the diode is there
to supply power to the e-bus till then. Beside having an alternate path to
feed the e-bus during normal operation, could the following be used instead?
During startup check list, turn master switch on AND e-bus switch on..... During
low voltage situations, just turn off master switch. This would remove the
need for the diode all together.
Bob
Message 28
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| Subject: | Re: battery capacity remaining |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Trampas wrote:
> Look at the Pulsar 200 Engine monitor.
It looks like an interesting box. I was considering a stand-alone engine monitor
like I had in my RV-4 (I had the Audio Flight Avionics AVA-10) but right now
I am leaning toward EFIS-1 from Blue Mountain Avionics for the CJ6A.
> Using the hall effect current sensors
> on the main battery wire and one on the alternator you can see how much
> current is going into the battery, how much power is being used by plane and
> how much power is remaining in battery. You can also monitor just about
> anything else you want from canopy switches to battery temperatures.
The problem is that the hall-effect sensors do not have the accuracy needed to
correctly monitor the energy left in the battery. You need a good shunt and about
14 bits of precision to properly integrate the amp-hours used and what is
left in the battery. You also need to know the amp draw very accurately in order
to do the calculation for Peukert's equation to know how much is really left.
This is probably not a big problem in an airplane because you are almost always
starting from a fully-charged battery. I have a 500AH 24V battery bank in my
boat whose energy content I need to track very accurately since I don't always
have the luxury of fully charging the battery every time I drain it partially.
I will probably post something on the care and feeding of batteries.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 29
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Paul Messinger wrote:
>> incorrect for most battery systems and even the 0.3V drop across the
>> schottky diode will ensure that your charging system will not properly
>> charge your second battery.
>
> That has not been my experience on what I am using. Most regulators (that I
> have inspected) are set somewhat high to get a rapid recharge. In any event
> consider the following room temp info from Odyssey. But then each of us must
> understand their aircraft needs and or fine some one who does.
The problem with voltage regulators with single settings is that they are set too
low to properly charge the battery and too high to maintain the battery on
float charge. The result is a battery that is always either undercharged or overcharged.
Actually, the one good thing in aircraft is that, in flight the battery
tends to get cold and that favors a higher float voltage, thus preventing
damage to the battery from overcharge.
Flooded cell batteries withstand abuse better than sealed batteries. Gel-cells
seem to withstand overcharge a bit better than do AGMs. I have had especially
bad luck with sealed AGM batteries running from standard aircraft alternators.
I feel that, if you want your AGMs and gell-cells to give long life, you need
a regulator that will do a proper three-stage charge (bulk charge, absorption
charge, float).
> The battery was discharged and then had a 5 ohm resistor placed across the
> battery for 28 days. The battery was then charges at const V of 13.5V for 48
> hours and achieved 97% of rated capacity.
Fully discharging a lead-acid battery of any sort is a really bad thing. Go look
at the manufacturers white papers on number of charge/discharge cycles relative
to depth of discharge. Most batteries can only withstand a handful of total
discharge cycles.
Another bad thing about what you did is that not all the cells have the same capacity.
The cell with the lowest capacity is actually going to go into reverse
charge from the other cells when it goes totally flat and the voltage across
it from the other cells is reverse polarity. Not good.
If you want to deep cycle a battery for some reason, i.e. you want to measure remaining
capacity, stop the discharge at 1.75V per cell (10.5V for a 12V battery).
A simple comparator circuit that will open a relay and disconnect all loads
from the battery when the battery reaches that stage of discharge is a good
thing.
> 13.5 plus 0.3V is 13.8V which is a commonly accepted minimum voltage for
> charging. I have yet to see an alternator internal or external regulator not
> set for at least 14.2V and most somewhat higher.
Flooded-cell and AGM batteries want about 14.5-14.6 V for proper absorption charging.
Gell-cells want about 14.2V. Flooded-cell and AGM batteries want about
13.2V for float charging (battery maintenance) while gell-cells want about 13.6V.
And these values change with temperature, that is they go down as the temperature
goes up and vice-versa.
So most charging systems in aircraft actually abuse the batteries. Once I learned
that I was no longer surprised that the life of an AGM in my Comanche was
never more than 2 years. Flooded-cell batteries last a lot longer as they just
gas and you can replace the water they lose.
OTOH, batteries are relatively cheap and replacing them every year is cheap insurance
even if you do abuse them.
> As my backup battery is not used for starting it starts each flight topped
> off so the current from the alternator is not charging but used for the
> backup engine systems some of which need to be always of for clean switching
> over if needed. Both on is not requires for proper operation.
I would look for your backup battery to fail first as it is constantly being overcharged.
OTOH, the diode drop may be saving it from a really early death.
> So my setup works well but others might not unless properly designed and
> verified.
I hear you.
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.360.838.9669 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 30
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| Subject: | Re: Power Diode Drops |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
I suggest you look at The ODYSSEY battery. Its very different in many
respects.
Embedded comments follow
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: AeroElectric-List: Re: Power Diode Drops
> --> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
> Paul Messinger wrote:
>
> >> incorrect for most battery systems and even the 0.3V drop across the
> >> schottky diode will ensure that your charging system will not properly
> >> charge your second battery.
> >
> > That has not been my experience on what I am using. Most regulators
(that I
> > have inspected) are set somewhat high to get a rapid recharge. In any
event
> > consider the following room temp info from Odyssey. But then each of us
must
> > understand their aircraft needs and or fine some one who does.
>
> The problem with voltage regulators with single settings is that they are
set too low to properly charge the battery and too high to maintain the
battery on float charge. The result is a battery that is always either
undercharged or overcharged. Actually, the one good thing in aircraft is
that, in flight the battery tends to get cold and that favors a higher float
voltage, thus preventing damage to the battery from overcharge.
True in a perfect world however autos have batteries that last for many
years and they have a single level reg.
> Flooded cell batteries withstand abuse better than sealed batteries.
Gel-cells seem to withstand overcharge a bit better than do AGMs. I have
had especially bad luck with sealed AGM batteries running from standard
aircraft alternators. I feel that, if you want your AGMs and gell-cells to
give long life, you need a regulator that will do a proper three-stage
charge (bulk charge, absorption charge, float).
The type of regulator is simply not practicle in an aircraft not needed in
my opinion. I do agree that if you have a boat or RV with huge battery banks
its a different story.
>
> > The battery was discharged and then had a 5 ohm resistor placed across
the
> > battery for 28 days. The battery was then charges at const V of 13.5V
for 48
> > hours and achieved 97% of rated capacity.
>
> Fully discharging a lead-acid battery of any sort is a really bad thing.
Go look at the manufacturers white papers on number of charge/discharge
cycles relative to depth of discharge. Most batteries can only withstand a
handful of total discharge cycles.
True but ODYSSEY is different ( they spec hundreds of total discharg
cycles), You would do well to find and download their publication
ODY-BR-101. Sorry no longer have the link but google works well.
I did not do the above test, I was quoting from ODYSSEY.
Things of interest. very low self discharge of up to two years. I have a
couple that were stored for 6 months and needed 15 min at 1 amp to top off.
They are rated at 400 discharge cycles to 100% DOD and 500 at 80%.
I would not use anything else in my aircraft and tried to have a discussion
some time ago and was shot down by Bob and others as the cheepest battery
annually replaced was deemed better. I disagree on that along with replacing
annually and putting the OLD battery in the backup spot. Frankly If I needed
a backup battery I would want the best and newest one not the old one that
was replaced on age.
Also there are simple methods (with no special equipment) to determine if
there has been significant loss of capacity on an annual basis so why change
the battery if its still like new. Not accurate enough for you perhaps but a
great indication of any significant problems
>
> Another bad thing about what you did is that not all the cells have the
same capacity. The cell with the lowest capacity is actually going to go
into reverse charge from the other cells when it goes totally flat and the
voltage across it from the other cells is reverse polarity. Not good.
Again I only quoted
>
> If you want to deep cycle a battery for some reason, i.e. you want to
measure remaining capacity, stop the discharge at 1.75V per cell (10.5V for
a 12V battery). A simple comparator circuit that will open a relay and
disconnect all loads from the battery when the battery reaches that stage of
discharge is a good thing.
Odyssey specs zero usefull charge at 11.6V 25C open circuit.
>
> > 13.5 plus 0.3V is 13.8V which is a commonly accepted minimum voltage for
> > charging. I have yet to see an alternator internal or external regulator
not
> > set for at least 14.2V and most somewhat higher.
>
> Flooded-cell and AGM batteries want about 14.5-14.6 V for proper
absorption charging. Gell-cells want about 14.2V. Flooded-cell and AGM
batteries want about 13.2V for float charging (battery maintenance) while
gell-cells want about 13.6V. And these values change with temperature, that
is they go down as the temperature goes up and vice-versa.
Agree but so what, and ODYSSEY is different from above. Regulators are made
including one designed by Bob and sold widely that has an temp sensor option
to adjust the voltage.
Again you seem to be a a purest where its not needed or possible.
Of course I went and got a AGM concord battery years ago when Bob was
pushing them and it failed in 6 months just being treated still on the shelf
etc. Bad cell one day.
> So most charging systems in aircraft actually abuse the batteries. Once I
learned that I was no longer surprised that the life of an AGM in my
Comanche was never more than 2 years. Flooded-cell batteries last a lot
longer as they just gas and you can replace the water they lose.
>
> OTOH, batteries are relatively cheap and replacing them every year is
cheap insurance even if you do abuse them.
That is your choice natch.
> > As my backup battery is not used for starting it starts each flight
topped
> > off so the current from the alternator is not charging but used for the
> > backup engine systems some of which need to be always of for clean
switching
> > over if needed. Both on is not required for proper operation.
>
> I would look for your backup battery to fail first as it is constantly
being overcharged. OTOH, the diode drop may be saving it from a really
early death.
I again you suggest looking at the subject battery. Also I seem to not win
no matter what. First my diode prevents full charge and now its being over
charged??? :-)
I have friends with large bus conversion RV's and gave up on one and the
other had to spend a couple of k bucks on batteries before I convinced him
to invest in the type of charger you suggest above. But its a very different
case in a small aircraft. and typically used less than 100 hours per year
and most flights around 1-2 hours.
Paul
Message 31
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"RV List" <rv-list@matronics.com>
| Subject: | Transponder not working |
--> AeroElectric-List message posted by: "Steve & Denise" <sjhdcl@kingston.net>
Today my transponder quit working. I have a GTX327 and an A-30 encoder wired using
Approach Avionics hub.
The transponder still shows the reply being carried out but ATC could not pick
me up.
The antenna is located far enough away from the comm antenna.
I have checked the BNC connector on antenna.
I'm going to order a different antenna and try that. The antenna I have is the
normal rod type with the ball on the end.
I've seen this problem with Microair transponders before and it turned out to be
a problem with the unit. I've never heard
of a problem with the 327.
I do let the encoder warm up. On this mornings flight it was intermittent and ATC
commented that I came in and out when
I maneuvered. Can't really prove this as ot doesn't happen all the time. Then after
flying for 1.5 hours I returned to the airport
and ATC never received my transponder at all. No position, no altitude.
Any other ideas of how to trouble shot this?
Thanks
Steve Hurlbut
RV7A
90 hours
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