Today's Message Index:
----------------------
1. 03:57 AM - Re: ANL current limiter location on rear battery installations (tomcostanza)
2. 05:38 AM - Deceptive Voltage? ()
3. 06:05 AM - Re: Deceptive Voltage? (Ken)
4. 07:14 AM - Re: Deceptive Voltage? (nuckollsr)
5. 07:36 AM - Re: Re: ANL current limiter location on rear battery installations (Robert L. Nuckolls, III)
6. 11:27 AM - LV warn light snafu? (messydeer)
7. 05:01 PM - 200G wiring with OVR (AVick)
8. 08:19 PM - Re: LV warn light snafu? (messydeer)
Message 1
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| Subject: | Re: ANL current limiter location on rear battery installations |
Bob,
With respect to:
> Small aircraft do not get circuit protection in
> the battery feeders to the starter and distribution
> busses.
Why does the battery feeder to the distribution buss not get protected?
Thanks,
-Tom
--------
Clear Skies,
Tom Costanza
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=304645#304645
Message 2
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| Subject: | Deceptive Voltage? |
7/13/2010
Hello Again Bob Nuckolls, Thank you for the prompt response copied below,
but my specific electrical theory question about the battery charger output
voltage possibly masking the battery's output voltage capability was not
answered.
In response to the statement: "...... a separate volt meter while cranking
the engine showed 13 plus volts."
You wrote: "This number appears bogus. A battery is incapable of delivering
energy at more than about 12.5 volts.........."
But what about the battery charger that is connected to the system, turned
on, and providing a higher than normal battery output voltage in its attempt
to recharge the battery while the engine was being cranked and the volt
meter readings were taken?
My electrical theory question is: "Could that battery charger output voltage
be affecting the reading obtained by the separate volt meter and indicate
that the battery is more capable than it really is in putting out amperage?"
Thank you.
'OC' Baker Says: "The best investment we can make is the time and effort to
gather and understand knowledge."
PS: Thank you also for writing and passing on the link to the article about
Shower of Sparks.
http://www.aeroelectric.com/articles/Shower-of-Sparks/ShowerOfSparks.pdf
I will pass that along to the RV-10 builder and his helpers.
==========================================================
Time: 08:01:28 AM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: Re: AeroElectric-List: Deceptive Voltage?
At 05:36 PM 7/11/2010, you wrote:
7/11/2010
Hello Bob Nuckolls and other Electrical Gurus,
Suppose you ran your battery down by spinning your first time to be
started O-540 Lycoming engine with the starter in order to preoil the
engine in your nearly finished RV-10. And maybe you did some other
things that ran the battery down.
Then you connected your small amperage output battery charger to the
battery and you attempted to start the Shower of Sparks equipped
engine without success. The engine was cranked OK, but the starting
vibrator just was not putting out.
A check of the system voltage in appropriate points with a separate
volt meter while cranking the engine showed 13 plus volts.
This number appears bogus. A battery is incapable
of delivering energy at more than about 12.5 volts
lightly loaded . . . a few amps. Given that most
batteries offer an internal resistance on the order
of .007 to .010 ohms, a 200A starter draw would be
expected to drop the battery terminal voltage by
perhaps 2 volts. So a terminal voltage of 10.5 or
lower is expected.
Is it possible that the voltage being seen was in fact the voltage
being put out by the battery charger as it attempted to recharge the
run down battery, but the amperage being put out by the run down
battery and battery charger together just was not enough current flow
to run the starting vibrator as well as crank the engine?
No, if the engine cranked at some speed you would
EXPECT to start it, then the battery is fine. The
shower-of-sparks system is designed to do two things:
(1) increased intensity of the sparking energy by
offering a repeating train of battery-supported
sparks and (2) DELAYING the delivery of ANY sparks
until just after TDC such that potential for kickback
is eliminated.
If your engine cranks but doesn't start, the battery
is fine and the SOS system is suspect. This article might
be of value in your quest for making all things right
with the world:
http://www.aeroelectric.com/articles/Shower-of-Sparks/ShowerOfSparks.pdf
Bob . . .
Message 3
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| Subject: | Re: Deceptive Voltage? |
OC
The thing is the battery voltage during cranking is the highest possible
voltage in the system during cranking. The charger voltage must be
pulled down to the same value unless you are measuring near the charger
and there is is high resistance between where you are measuring the
voltage and the battery. That would mean you have a second wiring issue.
So Bob really did answer the question. The 13 volt reading is
bogus/wrong/not related to you shower of sparks problem and is
meaningless/impossible unless you have the above mentioned second issue
or a large (100 amp ?) charger. Hope that helps a bit.
The answer to your electrical theory question is "No"
BTW I do enjoy your posts.
Ken
bakerocb@cox.net wrote:
>
> 7/13/2010
>
> Hello Again Bob Nuckolls, Thank you for the prompt response copied
> below, but my specific electrical theory question about the battery
> charger output voltage possibly masking the battery's output voltage
> capability was not answered.
>
> In response to the statement: "...... a separate volt meter while
> cranking the engine showed 13 plus volts."
>
> You wrote: "This number appears bogus. A battery is incapable of
> delivering energy at more than about 12.5 volts.........."
>
> But what about the battery charger that is connected to the system,
> turned on, and providing a higher than normal battery output voltage in
> its attempt to recharge the battery while the engine was being cranked
> and the volt meter readings were taken?
>
> My electrical theory question is: "Could that battery charger output
> voltage be affecting the reading obtained by the separate volt meter and
> indicate that the battery is more capable than it really is in putting
> out amperage?" Thank you.
>
> 'OC' Baker Says: "The best investment we can make is the time and effort
> to gather and understand knowledge."
>
> PS: Thank you also for writing and passing on the link to the article
> about Shower of Sparks.
>
> http://www.aeroelectric.com/articles/Shower-of-Sparks/ShowerOfSparks.pdf
>
> I will pass that along to the RV-10 builder and his helpers.
>
> ==========================================================
>
> Time: 08:01:28 AM PST US
> From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
> Subject: Re: AeroElectric-List: Deceptive Voltage?
>
>
>
> At 05:36 PM 7/11/2010, you wrote:
>
> 7/11/2010
>
> Hello Bob Nuckolls and other Electrical Gurus,
>
> Suppose you ran your battery down by spinning your first time to be
> started O-540 Lycoming engine with the starter in order to preoil the
> engine in your nearly finished RV-10. And maybe you did some other
> things that ran the battery down.
>
> Then you connected your small amperage output battery charger to the
> battery and you attempted to start the Shower of Sparks equipped
> engine without success. The engine was cranked OK, but the starting
> vibrator just was not putting out.
>
> A check of the system voltage in appropriate points with a separate
> volt meter while cranking the engine showed 13 plus volts.
>
> This number appears bogus. A battery is incapable
> of delivering energy at more than about 12.5 volts
> lightly loaded . . . a few amps. Given that most
> batteries offer an internal resistance on the order
> of .007 to .010 ohms, a 200A starter draw would be
> expected to drop the battery terminal voltage by
> perhaps 2 volts. So a terminal voltage of 10.5 or
> lower is expected.
>
>
> Is it possible that the voltage being seen was in fact the voltage
> being put out by the battery charger as it attempted to recharge the
> run down battery, but the amperage being put out by the run down
> battery and battery charger together just was not enough current flow
> to run the starting vibrator as well as crank the engine?
>
> No, if the engine cranked at some speed you would
> EXPECT to start it, then the battery is fine. The
> shower-of-sparks system is designed to do two things:
> (1) increased intensity of the sparking energy by
> offering a repeating train of battery-supported
> sparks and (2) DELAYING the delivery of ANY sparks
> until just after TDC such that potential for kickback
> is eliminated.
>
> If your engine cranks but doesn't start, the battery
> is fine and the SOS system is suspect. This article might
> be of value in your quest for making all things right
> with the world:
>
> http://www.aeroelectric.com/articles/Shower-of-Sparks/ShowerOfSparks.pdf
>
>
> Bob . . .
>
Message 4
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| Subject: | Re: Deceptive Voltage? |
> But what about the battery charger that is connected to the system, turned on,
and providing a higher than normal battery output voltage in its attempt to
recharge the battery while the engine was being cranked and the volt meter readings
were taken?
>
> My electrical theory question is: "Could that battery charger output voltage
be affecting the reading obtained by the separate volt meter and indicate that
the battery is more capable than it really is in putting out amperage?"
My apologies, I did miss that one. A battery charger is simply another energy
source. It has characteristics common to all energy sources in terms of potential
power, open circuit voltage, ability to deliver current (internal impedance),
noise, etc. A charge may be considered equivalent to a noisy battery (because
its got artifacts of internal electronics noise and/or rectified ac mains)
with a high internal impedance. The charger can produce no more output current
than its designers provided. Unless the charger is specifically designed for
cranking engines . . . see:
http://tinyurl.com/385snfg
then the effects of an operating charger on system voltage while cranking is insignificant.
It's not unlike paralleling a 60A alternator with an SD-8 alternator.
As long as you don't draw more than 8-10A, and SD-8 with a HIGHER regulation
setpoint might happily assume all the load and boost the voltage high enough
to cause the larger alternator to simply relax.
But as soon as the demand (in this case a cranking motor) exceeds the load carrying
capabilities of the source with the higher setpoint (in this case a charger),
the voltage sags to the point where the battery is willing and able to shoulder
some load . . . in this case, about 12.5 volts or lower. So the short answer
is, unless were talking about a boss-hogg charger that is capable of supporting
engine cranking loads at 13.0 volts (I don't think such a critter exists),
then the cited reading raises some questions as to measurement technique,
quality of the instrument, etc. I would not dispute what the individuals observed
but I will suggest that the reported readings raise more questions than they
answer and beg some explanation that will come from data we do not yet have.
I will suggest that the voltmeter be tested against another instrument believed
to be good. They should agree to within a 0.2 volts or so at 13v. Then connect
the voltmeter right at the battery terminals to watch the battery's ability
to pick up the cranking loads. Do the test with the charger connected, then repeat
with the charger disconnected. I suspect that voltage readings while cranking
under the two conditions will be under 12.5 volts and not significantly different
from each other.
Bob . . .
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=304665#304665
Message 5
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| Subject: | Re: ANL current limiter location on rear battery |
installations
At 05:53 AM 7/13/2010, you wrote:
><Tom@CostanzaAndAssociates.com>
>
>Bob,
>
>With respect to:
>
>
> > Small aircraft do not get circuit protection in
> > the battery feeders to the starter and distribution
> > busses.
>
>
>Why does the battery feeder to the distribution buss not get protected?
Because fat wires in dc electrical systems are
exceedingly hard to burn, hence there is no
value added in attempting to protect them. The
legacy design goals for DC systems in most vehicles
don't call for adding circuit protection to wires
until they become so small compared to the potential
energy sources (1000+ amps from a hard faulted battery)
that wiring protection is called for.
A fat wire in an airplane that's allowed to hat-dance
up to a chunk of airframe will probably burn a hole
in the airframe without opening the upstream
circuit protection. I've seen a 8AWG wire protected with
40A breaker burn an elevator cable in two without so
much as generating bad smells, blinking the lights
or popping a breaker.
Hence design goals and installation that suggest extra
attention to the insulation and support of fat wires combined
with a crew-controlled shut-off right at the battery
i.e. battery contactor.
Bob . . .
Message 6
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| Subject: | LV warn light snafu? |
I powered up my electrical system for the first time a couple days ago. No smoke.
Yeah! I have a Jabiru 3300 with their provided voltage regulator of some Japanese
make, I believe. The master switch is a sequential on (off, bat, bat +
alt) wired as shown in the attached schematic. I used Bobs Z-16 and Z-21 as the
basis for my system.
>From what I can tell, all but the LV warning light seems to work as I expected.
I wired the green voltage regulator wire to a panel mounted LED like shown in
the Jab manual on page 23 and 24.
At first, I left the two alternator output leads disconnected. When I turned on
the master to the middle 'bat' position, the LV warn LED came on nice and bright.
I figured this was normal, since the alternator is disconnected both by the
master switch and also by the two alt output leads being disconnected. But
when I flipped the master fully up to bat + alt, the light went out. I thought
it would have stayed on, since the alternator output leads are still disconnected.
So I connected the alternator output leads with jumpers, one to the COM terminal
on the alternator disconnect relay and the other to the LTBLU wire of the voltage
regulator. This time, when I turned the master to the first 'bat' position,
there was nothing. No light. Likewise in the 'bat + alt' position. Nada. And
with the master switch in the bat only position, disconnecting either of the
alternator output leads caused the red LED LV warn light to come on again. But
as before, it went out when the master switch is flipped to add the alternator.
I also noticed that when the LED LV warn light was on and then the master switched
off, it took several seconds for the light to fade and eventually go out.
But when the light went by switching the master from 'bat' to 'bat + alt', the
light went out immediately. I know the regulator is connected to a filter capacitor,
so I assume the battery charges up the capacitor when the master is on
'bat' and the charge bleeds out through the LED LV warn light when the battery
is disconnected.
You can download a PDF file I've attached or look at the smaller file inline below.
Most of the stuff is native Adobe, so there's much higher resolution available.
And it's in color! Otherwise, there's no difference.
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=304692#304692
Attachments:
http://forums.matronics.com//files/dans_electrical_schematic_643.jpg
http://forums.matronics.com//files/dans_electrical_schematic_112.pdf
Message 7
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| Subject: | 200G wiring with OVR |
Bob,
We are installing a B&C 200G PM alternator along with B&C's regulator and OVR.
I was planing on copying the layout for the SD-8 in Z-10/8.( just that part since
this is the only alternator for our simple Continental O-200 installation).
The 200G alternator is rated for about 12 amps. Can I stay with the 15 amp
in-line fuse or should I increase it to 20 amps?
I am connecting the in-line fuse at the starter contactor since my battery is
behind the seat and the battery contactor is behind the seat.
Why the differences between Z-13/ 8 and Z-10/8 for the SD-8 wiring?
1) Z-13 has 20AWG fuse link instead of the 15amp in-line fuse at the battery contactor
2) Z-13 has diodes on the S704-1 relay
3) Z13 has resistor across the capacitor
4) Z13 has bridge rectifier (?)and resistor to a LCL off of the alternator. What
is that for? What does LCL stand for?
Should I incorporate these in my installation?
5) Not sure how to tie-in a Low-Voltage indicator light in with either option.
Suggestions
6) I am installing a battery buss( fuse block) next to my main buss (fuse block)
under the panel The feed for the battery buss is a 10 awg wire from the battery
behind the seat to the panel. I was not planing on protecting that wire with
a in-line fuse. Should I?
It will be routed with the + & - fat wires . I would rather keep the two busses
together. Other option would be to put the battery buss behind the seat and than
I would have to run more wires toward the panel for , clock, aux power, cabin
lights etc. but they are all fused .
Thanks for your help.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=304710#304710
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| Subject: | Re: LV warn light snafu? |
Well, I think I found the problem. There will be an inline fuse between the COM
lead of the alternator disconnect relay and the RDAC for a tach signal. I have
the end into the COM lead just fine, but the other end was touching the firewall,
effectively grounding it. Once I took care of that, the LV light came on
exactly how I expected it to, both in 'bat only' as well as in the 'bat + alt'
positions.
In troubleshooting this, I started checking out numbers with my Fluke 83 VOM. The
wires and switches showed resistances of 0.2 to 0.4. The resistance across
the alt relay coil was 91 ohms. Voltage drops across the 3 reversing diodes were
all a little over 0.5V. There was no continuity across the crowbar OVM.
I should have connected the alternator output leads again before declaring a success.
I'll do that when I get out in the shop again.
And finally, assuming I've got the LV warn light problem fixed, is there anything
I can do to test the electrical system?
--------
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=304731#304731
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