Today's Message Index:
----------------------
1. 05:44 AM - Daytime Anticollision Lights ()
2. 06:11 AM - Daytime Anticollision Lights ()
3. 06:28 AM - Re: Daytime Anticollision Lights (BobsV35B@aol.com)
4. 07:26 AM - Re: Daytime Anticollision Lights (Robert L. Nuckolls, III)
5. 08:17 AM - Re: Daytime Anticollision Lights (Gaye and Vaughn)
6. 09:36 AM - Re: Daytime Anticollision Lights (C Smith)
7. 09:44 AM - Re: Daytime Anticollision Lights (C Smith)
8. 10:33 AM - Re: schematic revision (Eric M. Jones)
9. 11:21 AM - Re: Re: schematic revision (Bill Boyd)
10. 12:54 PM - Re: Battery Charging (Ken)
11. 02:30 PM - Re: Hand soldering reliability (Todd Heffley)
12. 03:27 PM - Battery Charging (Charles Brame)
13. 04:53 PM - Re: Battery Charging (Robert L. Nuckolls, III)
14. 05:50 PM - OV module wiring update/erratum (Bill Boyd)
15. 08:50 PM - Re: Battery Charging (Robert L. Nuckolls, III)
Message 1
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| Subject: | Daytime Anticollision Lights |
2/17/2007
Hello Bill Denton, Thanks for your input.
1) You wrote: "The intent of "the anticollision lights need not be lighted
when the
pilot-in-command determines that, because of operating conditions, it would
be in the interest of safety to turn the lights off" was to avoid blinding
other pilots with bright strobe flashes."
This may be true on the ground, but the bigger issue was a pilot suffering
vertigo while airborne in the clouds by having his anticollision light
flashing and reflected light coming into the cockpit.
2) You wrote: "But even the most stupid junior lawyer at the FAA
could nail you to the wall if you're operating all over the field without
the lights being on."
I don't think the FAA sees the anticollision light as essential for ground
use. I think that there are some airlines that as SOP have pilots turn on
the anti collision light as they are cleared to take the runway for take
off. All other times it is considered courteous to have them off when on the
ground.
OC -- The best investment we can make is the effort to gather and understand
knowledge. (Is that better Bob Nuckolls?)
Time: 09:06:40 AM PST US
From: "Bill Denton" <bdenton@bdenton.com>
Subject: RE: AeroElectric-List: Daytime Anticollision Lights
The intent of "the anticollision lights need not be lighted when the
pilot-in-command determines that, because of operating conditions, it would
be in the interest of safety to turn the lights off" was to avoid blinding
other pilots with bright strobe flashes.
You will notice that the regulations refer to turning them off when
conditions warrant, not to not turning them on at all. I recognize that
there might be conditions where a pilot might consider it inadvisable to
initially turn them on. But even the most stupid junior lawyer at the FAA
could nail you to the wall if you're operating all over the field without
the lights being on.
What you are going to run up against is a mentality that says "you don't
have to have them, but if you do have them, they better work and you had
better use them properly".
I would wonder if someone might not be jeopardizing your Airworthiness
Certificate if they operated in the manner suggested...
Message 2
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| Subject: | Daytime Anticollision Lights |
2/18/2004
Hello Konrad, Thanks for your input. I apologize for not previously
addressing you by name, but your name was not included in the posting that I
read that was provided through Bob Nuckolls.
1) You wrote: "....skip....Oh, and Nav-Lights/Strobes for collision
avoidance, but I don't
plan to fly at nighttime.....skip....."
And I wrote: "Please note what FAR Sec. 91.209 (b) says about operating
anticollision
lights in the daytime, as well as from sunset to sunrise, if the aircraft is
equipped with an anticollision light system."
I wrote that because I was concerned that some reader, not necessarily you,
might conclude that the sole considerations he would have about installing,
or not, and operating anticollision lights was electrical load and whether
he was operating between sunset and sunrise. I did not want to let that
erroneous conclusion stand without some clarification.
2) You wrote: "But blink once and schwup-di-wup we deviate into a whole
different
direction right quick. How did we get from Electrics & Physics to FAA
Rules & Lawyers so darn quick???"
We got there because fairly early on in my homebuilding experience I learned
that we builders, including myself, were so focused on building that the
rules pertaining to our configuring, building, registering, certifying, and
operating our aircraft were way in the back of our minds. Some times that
condition rose up to bite us and we said: "If only I had known that
earlier".
I also learned that the FAA and EAA had some knowledge of how things could
and should work in the homebuilding community that was not readily apparent
by just reading the FAR's. So as I got bruised and educated in this arena I
made it my goal to share what I have learned with other builders and pilots.
There are still enough gray areas so that no one, including me, has all the
definitive answers, but I'd still like to share what I have learned --
hopefully for the benefit of others.
OC -- The best investment we can make is the effort to gather and understand
knowledge (then share it).
Time: 10:04:46 AM PST US
From: "Konrad L. Werner" <klwerner@comcast.net>
Subject: Re: AeroElectric-List: Daytime Anticollision Lights
I am still amazed me how this thread came into life? My original
question that started it was to see if my SD-8 would be an adequate
alternator to supply enough energy to a certain setup...
But blink once and schwup-di-wup we deviate into a whole different
direction right quick. How did we get from Electrics & Physics to FAA
Rules & Lawyers so darn quick???
Whatever will be mounted in the ship will be used in accordance to
Rules, Regs and/or Logic, ...so is my SD-8 alternator adequate or not
for the specific demands mentioned earlier?
I still don't know what the best Primer is? Any ideas anyone ???
Message 3
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| Subject: | Re: Daytime Anticollision Lights |
Good Morning OC,
May I add a little comment from one who has spent a lot of wasted time
taxiing around airports?
The gripe by folks on the ground mainly concern strobe lights. When they
first came on the scene, if you turned one on while still on the ground,
somebody was sure to ask that it be turned off. The Powers That Be had some testing
done and we were all informed that the flash was of such short duration that
there was no way it could affect our night vision. Nevertheless, the
complaints continued and still do to this day.
However, most of us really liked having rotating beacons lit while taxiing.
If you have ever sat in a cockpit twenty feet above the surface, you have
realized that it is very difficult to spot a small airplane that has only
position lights for conspicuity.
The standard, new then, but now old fashioned, rotating Grimes Beacon worked
very well, but the ones I liked the best were the ones mounted on the belly.
That light never could shine into anyone's eye, yet it lit up a broad space
on the ground. While I came very close to taxiing over small aircraft
several times, I never missed seeing one that had a belly beacon lit.
As an aside, it is my opinion that the most conspicuous light of all is the
Grimes oscillating beacon mounted on the belly!
On my personal airplanes, I have always installed a belly beacon. If I was
flying an airplane not so equipped, I would use the one on top. If the
airplane has only strobes, I would very carefully watch for other airplanes and
turn on the strobe when one got within a hundred feet of me. If that elicited a
snide remark about "getting that idiot to turn off his strobe", so be it!
The accident where a US Air flight landed on a commuter holding in position
would probably not have occurred if the commuter had been equipped with a
beacon either in addition to or instead of the strobe.
If I Recall Correctly, it was company policy for the commuter to not turn on
the strobe until takeoff clearance had been received. Since they had no
beacon, the only conspicuity lighting that was available for the US Air pilots
to
see was that little white tail light.
I want a rotating (or oscillating!) beacon on my airplane. With or without
strobes.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
In a message dated 2/18/2007 7:46:12 A.M. Central Standard Time,
bakerocb@cox.net writes:
--> AeroElectric-List message posted by: <bakerocb@cox.net>
2/17/2007
Hello Bill Denton, Thanks for your input.
1) You wrote: "The intent of "the anti collision lights need not be lighted
when the
pilot-in-command determines that, because of operating conditions, it would
be in the interest of safety to turn the lights off" was to avoid blinding
other pilots with bright strobe flashes."
This may be true on the ground, but the bigger issue was a pilot suffering
vertigo while airborne in the clouds by having his anti collision light
flashing and reflected light coming into the cockpit.
2) You wrote: "But even the most stupid junior lawyer at the FAA
could nail you to the wall if you're operating all over the field without
the lights being on."
I don't think the FAA sees the anti collision light as essential for ground
use. I think that there are some airlines that as SOP have pilots turn on
the anti collision light as they are cleared to take the runway for take
off. All other times it is considered courteous to have them off when on the
ground.
OC -- The best investment we can make is the effort to gather and understand
knowledge. (Is that better Bob Nuckolls?)
Message 4
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| Subject: | Re: Daytime Anticollision Lights |
At 08:40 AM 2/18/2007 -0500, you wrote:
>
>2/17/2007
>
>Hello Bill Denton, Thanks for your input.
>
>1) You wrote: "The intent of "the anticollision lights need not be lighted
>when the
>pilot-in-command determines that, because of operating conditions, it would
>be in the interest of safety to turn the lights off" was to avoid blinding
>other pilots with bright strobe flashes."
>
>This may be true on the ground, but the bigger issue was a pilot suffering
>vertigo while airborne in the clouds by having his anticollision light
>flashing and reflected light coming into the cockpit.
>
>2) You wrote: "But even the most stupid junior lawyer at the FAA
>could nail you to the wall if you're operating all over the field without
>the lights being on."
>
>I don't think the FAA sees the anticollision light as essential for ground
>use. I think that there are some airlines that as SOP have pilots turn on
>the anti collision light as they are cleared to take the runway for take
>off. All other times it is considered courteous to have them off when on
>the ground.
I recall my first trip to the airplane with the
flight instructor wherein he suggested that it
was a good thing to turn on the flashing beacon
just before starting the engine as a notice to
others that you were about to become a potential
hazard . . .
In the past few days, we've had two small children
killed under the wheels of cars here in Wichita.
One small fellow had pulled away from his grandfathers
grip to catch up with his brother who had crossed
the lane to a drive-up window ahead of him. The car had
stopped for the mother and other brother. The car
was moving forward again when the second child decided
to make his move.
These incidents have sparked a lot of discussion
in the media among folks who decry how "unsafe
our society has become for children". No doubt
the promulgators of hazard will become vulnerable
to legal attacks of one kind or another.
I recall from my childhood the loss of several
children in my school due to various accidents.
While our little town grieved over the loss
of these individuals, I don't remember any call
for new initiatives with a goal of reducing risks
of similar events in the future. But like dozens of
discussions in various venues at the FAA about
lighting this, flashing that and prescribing sanctions
against scofflaws, our town will be blessed with
the opinions of many who will offer their own
calls for "changes in society's behavior to
prevent this from ever happening again".
Years after these meetings took place, new
initiatives erected and sanctions prescribed,
the reasons offered by teachers for their
existence will be as varied (and perhaps even
conflicting) as the variety of rationales offered
for the use or non-use of lighting on our airplanes.
Long after the reasons that were offered when
the rules were crafted are forgotten, the rules
will still exist, propagandists will still be rationalizing
them in a variety of ways. I use the word propagandist
as opposed to teacher because most are simply
parroting what they've heard or interpreted on their
own without benefit of knowing the thinking of
those who crafted the rules years ago and in
places far away.
The simple ideas behind exterior lighting are profound.
Lights help you see. Lights help people see you.
ANYTHING one does to make their airplane stand out
from the environs has the obvious value of reducing
risk. By how much? Nobody will ever know by virtue
of a double-blind, scientific study of numbers
derived from repeatable experiments.
Nonetheless, fellow pilots, regulators and even your next
door neighbor will have an opinion bolstered by
some anecdote describing how two airplanes came
together . . . or some kid met an untimely end
in the McDonalds drive-thru. If running lights
has some non-zero value for reducing risk, nobody
is likely to sanction you for having lights.
However, they might well decide to make an example of
you for not having shown a light.
The ultimate responsibility for doing a good thing
about lighting an airplane rests with us and
not upon those who run around with rule books under
their arms trying to justify next year's raise.
Being good citizens in the air and on the ground
should be driven by something other than
(1) dependance upon anecdotal interpretation of
rules (2) or done just to avoid sanctions for having
broken the rules.
The best thing we can do here on the List is figure
out ways to "make it happen" and perhaps concentrate
less on whether or not it should happen and why.
>OC -- The best investment we can make is the effort to gather and
>understand knowledge. (Is that better Bob Nuckolls?)
Makes sense to me my friend!
Bob . . .
Message 5
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| Subject: | Re: Daytime Anticollision Lights |
Long before manufacturers were required to wire cars and motorcycles to run
with their headlights on, I always turned the headlights on my motorcycle
on, even though the bike that I had at the time could barely keep up with
running the lights and charging the battery at the same time
However, I did not feel that this made me safe. In many it helped, but I
recall one instance in which my back-up plan (assuming that no one saw me)
is probably responsible for the fact that I still have a right leg. As a big
car rushed up to the stop sign on my right, I was watching for the flicker
of recognition in his eyes. Seeing none, I started to swerve left. Sure
enough, after a rolling stop, he proceeded to pull across the street. The
early beginning of my swerve and the act of raising my leg above the
handlebars saved my leg. He didn't touch me, but I still remember my leg
passing over his hood and the hair standing up on the back of my neck.
So how does this relate? Why not use every aid available to enhance your
safety and also stay alert and aware of your surroundings. The cockpit is no
place for complacency and daydeaming, nor is the seat of a motorcycle.
Vaughn Teegarden
66 years old and looking forward to many more years of safe flying and
riding
Message 6
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| Subject: | Daytime Anticollision Lights |
I have always wondered why my instructor always demanded that I turn off my
strobes while on the ground. I thought the purpose of the strobes was to
make my aircraft unmistakable. I have never been so disturbed by the
flashing of strobes of other aircraft, that I could not fulfill my duties as
pilot in command of my aircraft. Other than having read that this is somehow
"airport etiquette" in a Cessna PPL course book, and parroted by many
instructors, I simply don't understand it's real compliment to safety.
I would rather be a standout on the taxi-way, than have my aircraft blend
into the cacophony of lights on the field and have another aircraft or
vehicle taxi into/land on top of me. If the lights bother someone, I suggest
you not stare directly into the strobe. I'm sure that some will say that I
should not worry about other aircraft, I should know if they are coming in
to land, but more than once I've had aircraft swoop in to the runway without
self announcement on the CTAF, or for that matter flying a proper pattern.
When my aircraft is in motion or taxiing anywhere other than the hangar
area, I'm going to use all of the lighting available, to ensure I'm seen.
Sorry to have bothered you.
I'm sure the flames will start, and the name calling will follow, but I'd
rather be an a*****e than an accident statistic.
Craig Smith
Message 7
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| Subject: | Daytime Anticollision Lights |
I too ride a motorcycle, and have started using the Kynon Headlight flasher,
and the Kynon brake light flasher. After being clipped from behind while
waiting to make a turn, I made sure that I'm visible from all directions.
They get you noticed when coming, and there is no doubt to those behind that
you are braking. Anything to make me stand out from the blur of traffic, is
a good thing.
Craig Smith
Do not archive
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Gaye and
Vaughn
Sent: Sunday, February 18, 2007 11:17 AM
Subject: Re: AeroElectric-List: Daytime Anticollision Lights
--> <vaughnray@bvunet.net>
Long before manufacturers were required to wire cars and motorcycles to run
with their headlights on, I always turned the headlights on my motorcycle
on, even though the bike that I had at the time could barely keep up with
running the lights and charging the battery at the same time
However, I did not feel that this made me safe. In many it helped, but I
recall one instance in which my back-up plan (assuming that no one saw me)
is probably responsible for the fact that I still have a right leg. As a big
car rushed up to the stop sign on my right, I was watching for the flicker
of recognition in his eyes. Seeing none, I started to swerve left. Sure
enough, after a rolling stop, he proceeded to pull across the street. The
early beginning of my swerve and the act of raising my leg above the
handlebars saved my leg. He didn't touch me, but I still remember my leg
passing over his hood and the hair standing up on the back of my neck.
So how does this relate? Why not use every aid available to enhance your
safety and also stay alert and aware of your surroundings. The cockpit is no
place for complacency and daydeaming, nor is the seat of a motorcycle.
Vaughn Teegarden
66 years old and looking forward to many more years of safe flying and
riding
Message 8
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| Subject: | Re: schematic revision |
> ...Bench testing of the original design has exposed a flaw in the way the Perihelion
OV module is wired in. The module cannot tolerate over 18 volts on any
of its terminals for more than a few milliseconds. Not
> very robust-sounding for a module designed to trip at 16.2 volts, and
> an expensive lesson to learn the hard way, but in the end,...
Bill, and all my fine customers, et al. To clarify--The Perihelion Design L-OVM
is designed to shut down voltages over 16.2V that exist for 200 mS or more. This
is usually used in combination with the WhackJack-18 that clamps load dump
voltages over about 18V and will do it for over for more than 500 mS.
Of course one might think, "Gee..it's made to shut off the power at 16.2V but BLOWS
UP at 18V??" This is not quite what happens. The recent Maxwell Power OVM
comparison (attached) also seems to have this point confused. (Although, thanks
to their table I am considering raising my price substantially! BTW--The
L-OVM also cuts the B leads with an external contactor.)
The L-OVM is rated 18V because it has 20V Zener clamps. The module will pass DO-160
20/40/300V transients, automotive 60V transient requirements and will even
help a bit in a lightning strike--but it is not made to withstand more than
18V continuously. This is not a design weakness, it is exactly what the device
was designed to do. Generally, any device with transient voltage suppression
will be very unhappy if these same transient voltages are applied continuously.
I can design and build the L-OVM for any voltage, but it turns out that the Mosfets
get bigger and more expensive in a hurry for the same performance, and the
packaging issues abound.
Description of Operation for the L-OVM is attached.
Hope this clears up some things.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones@charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p-856#95856
Attachments:
http://forums.matronics.com//files/lovm_description_of_operation_865.pdf
http://forums.matronics.com//files/monitorandnbspoverview_782.pdf
Message 9
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| Subject: | Re: schematic revision |
My OVM's destruction resulted form not applying it the way Eric said
to (well, his schematic is not very similar to mine, but shows the way
Bob used to recommend controlling an I-VR alternator with a B-lead
contactor (but using MOSFET circuit interruption rather than crowbar
breaker-popping approach.) I should have been able to read between
the lines and deduce that, even in my different circuit topology, the
connections of the OVM to the circuit should all have been made on the
cold side of the OV event. It does say in the spec sheet that 18
volts is the maximum input voltage.
Eric, despite my mea culpa above, I note the absence of any reference
to WhackJacks or other suppression at the 18 volt level in the
application notes included with the OV module I purchased from you.
If it's that important, you might consider revising the documents.
Thanks for your time on the phone the other evening.
-Bill B
On 2/18/07, Eric M. Jones <emjones@charter.net> wrote:
>
>
> > ...Bench testing of the original design has exposed a flaw in the way the Perihelion
OV module is wired in. The module cannot tolerate over 18 volts on any
of its terminals for more than a few milliseconds. Not
> > very robust-sounding for a module designed to trip at 16.2 volts, and
> > an expensive lesson to learn the hard way, but in the end,...
>
>
> Bill, and all my fine customers, et al. To clarify--The Perihelion Design L-OVM
is designed to shut down voltages over 16.2V that exist for 200 mS or more.
This is usually used in combination with the WhackJack-18 that clamps load dump
voltages over about 18V and will do it for over for more than 500 mS.
>
> Of course one might think, "Gee..it's made to shut off the power at 16.2V but
BLOWS UP at 18V??" This is not quite what happens. The recent Maxwell Power
OVM comparison (attached) also seems to have this point confused. (Although, thanks
to their table I am considering raising my price substantially! BTW--The
L-OVM also cuts the B leads with an external contactor.)
>
> The L-OVM is rated 18V because it has 20V Zener clamps. The module will pass
DO-160 20/40/300V transients, automotive 60V transient requirements and will even
help a bit in a lightning strike--but it is not made to withstand more than
18V continuously. This is not a design weakness, it is exactly what the device
was designed to do. Generally, any device with transient voltage suppression
will be very unhappy if these same transient voltages are applied continuously.
>
> I can design and build the L-OVM for any voltage, but it turns out that the Mosfets
get bigger and more expensive in a hurry for the same performance, and
the packaging issues abound.
>
> Description of Operation for the L-OVM is attached.
>
> Hope this clears up some things.
>
> --------
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge, MA 01550
> (508) 764-2072
> emjones@charter.net
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p-856#95856
>
>
> Attachments:
>
> http://forums.matronics.com//files/lovm_description_of_operation_865.pdf
> http://forums.matronics.com//files/monitorandnbspoverview_782.pdf
>
>
Message 10
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| Subject: | Re: Battery Charging |
http://www.shaka.com/~kalepa/desulf.htm
CH701 wrote:
>
>Speaking of battery charging, a recent issue of Sport Aviation had an
>article entitled "Pulse De-sulfator for Lead-acid Batteries." It described
>the process of resurrecting weak or sulfated batteries, and included some
>theory and a schematic of a circuit to address the process. I'm just
>wondering what this community has to offer on the subject...
>
>Here's a link to the authors site:
>http://www.geocities.com/powertugs/eaa79parts.html
>
>Todd Henning
>Scratch CH701 Builder
>
>
Message 11
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| Subject: | Re: Hand soldering reliability |
Had to rant.
For those of you who have not had the pleasure of working under these
tyanical systems...
When you hear the words Six Sigma, be prepared to stop what you are
doing and build some spreadsheets, attend MANY meetings, and synergize
team-to-team stratagies to maximize future deliverables.
BUT MOST OF ALL, YOU WILL STOP PRODUCING USEFUL
products/services/advancements.....PERIOD.
do not archive
Todd
--
Todd Heffleytodd@toddheffley.com
(817)845-0145
Message 12
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| Subject: | Battery Charging |
Bob,
Assume you have two 17 AH batteries hooked in parallel, one is dead
or very low, the other has a decent charge. If a "smart" charger will
continue a high voltage until both batteries are charged before
dropping to a sustaining level, can the charged battery in this case
be damaged while bringing (or attempting to bring) the low or dead
battery up to a fully charged state?
Charlie Brame
RV-6A N11CB
San Antonio
------------------------------------------------------------------------
--------
> Bob Knuckles wrote:
>
>
> You wait for a period of time -OR- until recharge current
> drops below some nominally low value. I've heard Concord
> folks cite "100 milliamps" as the indication that the battery
> is no longer converting discharged chemistry into charged
> chemistry. After this time, it's useful to drop the charger's
> output voltage to a "sustaining" level that cannot charge but
> only offset internal leakages (self discharge) currents that
> exist in EVERY battery technology.
>
> To insure that all batteries in an array of two or more
> see the same terminal voltage during the recharge-sustain
> process, they must be in PARALLEL.
>
> -------------------snip---------
>
> Absolutely. A 1.5A charger can deliver 1.5AH of charge
> per hour. Hook dead 32, 18 and 10 AH batteries in
> parallel and you've tasked the charger with delivering
> enough energy to replenish all batteries in the array . .
> or 60 AH. One should expect this process to take 40+
> hours to complete. All batteries are being recharged on
> the same time curve with each getting a share of the
> 1.5 AH/HR that's available from the charger.
>
> Bob . . .
>
Message 13
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| Subject: | Re: Battery Charging |
At 05:26 PM 2/18/2007 -0600, you wrote:
>Bob,
>
>Assume you have two 17 AH batteries hooked in parallel, one is dead or
>very low, the other has a decent charge. If a "smart" charger will
>continue a high voltage
No, a CONSTANT CURRENT flows until BOTH batteries present
a LOAD sufficiently low that (1) voltage rises to a level
consistent with a high state of charger or (2) the
charger goes into voltage limit where it now watches
for recharge current to drop below some nominal but
small value . . . 100 mA or less is typical. It doesn't
matter that one (discharged) battery takes the lion's
share of the current available. The chemistry in the
charged battery simply relaxes until the discharged
battery catches up to the partially/fully charged
battery.
>until both batteries are charged before dropping to a sustaining level,
>can the charged battery in this case be damaged while bringing
>(or attempting to bring) the low or dead battery up to a fully charged state?
No, there are a number of myths circulated for
decades and even posited here on the List that
hooking a fully or highly charged battery to a
discharged one would cause (a) damage to one or
both batteries, (b) the dead battery would "suck
down" the energy stored in the charged battery,
(c) the charged battery to become over-charged
if they were connected in parallel to a charging
source, etc. etc. etc.
Yes, if you hook a fully charged battery to a dead-dead
battery, there is a momentary and relatively large
current flow from the hot battery to the dead one.
But if the connection is maintained and the energy
transfer measured, one soon finds that a tiny
(less than 1%) of the charged battery's energy
is lost into the dead battery. After all,
the charged battery delivers energy at something
just over 12.5 volts and 12.5 volts cannot
significantly charge a dead battery.
Hooking two good batteries (one discharged and
one charged) to the same charging source be
it a Battery Tender, other smart charger or
your aircraft's alternator presents no hazards
nor special concerns for outcome of things
once the charger's green "battery charged"
light comes on.
Bob . . .
----------------------------------------
( IF one aspires to be "world class", )
( what ever you do must be exercised )
( EVERY day . . . )
( R. L. Nuckolls III )
----------------------------------------
Message 14
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| Subject: | OV module wiring update/erratum |
In the process of changing my panel wiring to reflect the drawings I
recently posted here, I stumbled upon the need for one more change
(hopefully the last one) - by leaving in place the damaged OV module
that was fried during testing with a zero-to-18.3 volt power supply.
It became immediately apparent that there was a short somewhere (well,
duh!) and ended up blowing a 10 amp fuse in series with the avionics
standby battery. Ohmmeter probing revealed a short-circuit hard fault
existed from module pins 1 and 3 to pin 5 (ground). In my latest
iteration, I had connected pins 2,3 and 4 to one 5-amp fuse on the
avionics bus, and pin 1 plus one of the fast-on tabs to a second 5a
fuse on the same bus. For whatever reason, the fault current was
evenly-enough distributed between those two fuses that they both held,
while the 10 amp fuse in the battery + lead blew.
**The disturbing thing is that the entire 10 amp fault current was
carried to ground by the 22 AWG wire on pin 5. Sustained testing
could have gotten this wire really toasty**
To protect this ground wire indirectly at the 5 amp level, I have
moved all connections from the OV module to the avionics bus onto a
single connection protected by a 5 amp fuse (about time, eh? ;-) This
has an additional benefit of preventing a blown OV module fuse from
taking out the trim system that formerly shared that fuse on the bus.
(Standard good-engineering practice, I know).
I realize that an _undamaged_ module won't be presenting any shorts to
ground when wired in this way, but in the event the replacement module
ever eats its lunch (I don't think it will, following the re-design of
my schematic), I don't want a fault current of potentially 15 amps
traveling down a 22 gauge ground wire.
Eric, see any problems with the way I've done it now?
-Bill
Message 15
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| Subject: | Re: Battery Charging |
At 03:56 PM 2/18/2007 -0500, you wrote:
>
>http://www.shaka.com/~kalepa/desulf.htm
>
>CH701 wrote:
>
>>
>>Speaking of battery charging, a recent issue of Sport Aviation had an
>>article entitled "Pulse De-sulfator for Lead-acid Batteries." It described
>>the process of resurrecting weak or sulfated batteries, and included some
>>theory and a schematic of a circuit to address the process. I'm just
>>wondering what this community has to offer on the subject...
>>
>>Here's a link to the authors site:
>>http://www.geocities.com/powertugs/eaa79parts.html
This article offers one of the more robust desulfation
philosophies and probably the most popular version.
I wish I had more hard data on this class of battery
service aid. At the moment, I'm aware of no battery
manufacturer that endorse this technology.
Yeah, there are some who would suggest, "folks who
build batteries are not interested in user applied
technologies that prolong the life of their products.
It cuts into battery sales." To which I confidently
reply, "horse pucky".
I've been to the R&D labs of several manufacturers
and witnessed their efforts to fine tune chemistry,
manufacturing processes and field service recommendations
all of which go to improving on the manufacturer's competitive
position in the marketplace. They also publish recommendations
for how their batteries should be treated in the field
to improve on customer satisfaction. When I asked these
folks about desulfators, not a one said that they're
detrimental to battery service life but to a man, they
were unable to endorse them as having a quantifiable
return on investment after having tested several
products. Of course I don't know WHICH devices were
tested . . . perhaps they missed putting their hands
on Smiley Jack's One True Battery Desulfator.
I can see no reason why one should NOT use any of
these devices but I'm unaware of a single repeatable
experiment that says they're a really good thing to
do. If anyone runs across a report that proffers
any hard data, I'd be pleased to know about it.
My shop DAS computer went out the door yesterday
'cause it's also used to program the processors
for and exercise the finished product for a programmable
pressure controller I've been building for a client.
I've off-loaded the manufacturing so that I can
spend more time getting a new line of AEC products
on line. I'll be acquiring another computer in the
next few days so that I can resume the battery
charger experiments we've been conducting over
the past few days.
Bob . . .
----------------------------------------
( IF one aspires to be "world class", )
( what ever you do must be exercised )
( EVERY day . . . )
( R. L. Nuckolls III )
----------------------------------------
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