Today's Message Index:
----------------------
1. 12:28 AM - Should 22K uF capacitor be fused? ()
2. 03:50 AM - Re: Z-16 (Rodney Dunham)
3. 08:35 AM - curious questions (Michael T. Ice)
4. 08:54 AM - Crimp on terminals (Grant Neilson)
5. 09:57 AM - Re: Relay and capacitor info needed (Robert L. Nuckolls, III)
6. 09:58 AM - Re: Should 22K uF capacitor be fused? (Robert L. Nuckolls, III)
7. 10:04 AM - Z-11 (Gaye and Vaughn)
8. 10:05 AM - Re: Crimp on terminals (Ron Quillin)
9. 10:06 AM - Re: Z-16 (Robert L. Nuckolls, III)
10. 11:29 AM - Z-16-not Z-11 (Gaye and Vaughn)
11. 01:17 PM - Battery insulation (Leo Holler)
12. 01:38 PM - Re: Battery insulation (BobsV35B@aol.com)
13. 01:55 PM - Re: Relay and capacitor info needed ()
14. 05:01 PM - Re: Crimp on terminals (Larry Mac Donald)
15. 05:40 PM - Re: curious questions (Larry Mac Donald)
16. 05:52 PM - Alternator (Rino Lacombe)
17. 06:11 PM - Re: Battery insulation (Leo Holler)
18. 07:06 PM - Re: Re: Battery insulation (BobsV35B@aol.com)
19. 07:37 PM - Re: Battery insulation (Jim Jewell)
Message 1
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Subject: | Should 22K uF capacitor be fused? |
Hello Bob
I was reading a post you made from 01-2000 about putting a 10 amp fuse on
the 22k uF capacitor of a Rotax internal generator.
Do you still advocate fusing the capacitor? I plan on using a 22K uF 35V
with a 105C rating.
Thx.
Ron Parigoris
Below is some of 2000 post you made:
The general rull of thumb for 60 Hz power supplies is 1,000
uFd per amp of power supply capacity. Applying the same rule
to the 18A Rotax alternator puts the 22,000 uFd device right
in the ballpark.
The capacitor does it's job by looking as
if it were a dead short to the AC voltages on the system.
ANY device connected in series with the capacitor raises
it's equivalent series resistance value and degrades it's
ability to do the job. A 10A fuse is a good idea . . . capacitors
rarely short but it's not impossible. Better to open a fuse
that blow the end out of the capacitor . . . they stink
and are really messy.
Capacitors rated for operation at 85 degrees C are standard.
Further, they don't have to be big either. A 33,000 uFd,
16 volt device can be had with an envelope of 1.4" diameter
and 2.13" long. You want a computer grade device with 10-32
screw terminals. These have the lowest internal resistance
and are most suited for attaching the fat wires used to wire
the alternator system.
Message 2
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Bob said...
"It's unlikely that anyone on staff at your supplier can discuss
applications and options with any logic. They're only parroting information
fed to them by others who are equally un-informed as to how you meet your
design goals."
How right you are! I called Jabiru USA to ask about the voltage regulator
they sell and install on their Jabiru engines and aircraft. They could not
tell me any more about the regulator than "It's solid state." They also
didn't seem to understand the physics of the PM Dynamo in their engines.
After looking at their wiring in the few planes under construction, I
concluded they could use a 'Connection Seminar! But, I kept my mouth shut. I
was there to learn from them. And it was a good seminar in all other
respects.
Rod
_________________________________________________________________
Download Messenger. Join the im Initiative. Help make a difference today.
http://im.live.com/messenger/im/home/?source=TAGHM_APR07
Message 3
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Subject: | curious questions |
Hello,
A friend of mine that occasionally helps me work on my RV-9 has asked me some
questions that I can't answer satisfactorily. He is a great guy and has a very
curious mind, he owns and works on boats, cars, etc, but doesn't have a history
with aircraft. These are the questions in his own words posted below. Any
help will be gratefully accepted.
In the course of helping a friend construct an RV 9 I had the opportunity to examine
the electrical system design. I was puzzled at the use of a master relay
(solenoid) to switch the entire electrical system. A number of questions occurred
to me regarding this design:
The questions: How much amperage draw does the solenoid consume simply being energized?
At what voltage does the Solenoid release? And why this design?
It seems to me inserting the master relay (solenoid) into the electrical system
has no benefit and some detriment.
The detriments are: 1. constant draw on battery when energized. 2. greater complexity.
3. increased weight (all 6 oz of the solenoid) 4. failure of the complete
electrical system if a) the solenoid fails, or b) if you have alternator failure
and voltage drops low enough to allow the solenoid to not close/open (we
have all heard the clicking of the starter solenoid on a run down car battery-
but the radios still work).
Contrast this with the benefit- uh- what benefit? There is the same amount of
current flowing to the panel from the battery whether it comes via the relay
or via a straight run to a master switch. Starter current continues to utilize
the starter solenoid. Alternator output current can be routed directly to the
battery since the field voltage can be turned off via the master switch (and
as I understand the design, inserting a fuse in the alternator output line).
My limited knowledge may be impeding my appreciation of the function of the master
relay- but I have been pondering this- and can't come up with a good rationale.
On large aircraft, where you have significant electrical loads that are
distant from the cockpit, it would make sense to use a relay so that you minimize
voltage drop and/or weight by eliminating long wiring runs. But this doesn't
seem to be the case here. The argument regarding electromagnetic fields near
radios does not hold up since the loads are the same whether switched through
a relay or not.
I guess the bottom line is- There are some VERY smart people building these aircraft.
Surely there is a good reason for the master relay design- I just want
to know what it is?
In the course of helping a friend construct an RV 9 I had the opportunity to
examine the electrical system design. I was puzzled at the use of a master relay
(solenoid) to switch the entire electrical system. A number of questions occurred
to me regarding this design:
The questions: How much amperage draw does the solenoid consume simply being energized?
At what voltage does the Solenoid release? And why this design?
It seems to me inserting the master relay (solenoid) into the electrical system
has no benefit and some detriment.
The detriments are: 1. constant draw on battery when energized. 2. greater complexity.
3. increased weight (all 6oz of the solenoid) 4. failure of the complete
electrical system if a) the solenoid fails, or b) if you have alternator failure
and voltage drops low enough to allow the solenoid to not close/open (we
have all heard the clicking of the starter solenoid on a run down car battery-
but the radios still work).
Contrast this with the benefit- uh- what benefit? There is the same amount of
current flowing to the panel from the battery whether it comes via the relay or
via a straight run to a master switch. Starter current continues to utilize
the starter solenoid. Alternator output current can be routed directly to the
battery since the field voltage can be turned off via the master switch (and as
I understand the design, inserting a fuse in the alternator output line).
My limited knowledge may be impeding my appreciation of the function of the master
relay- but I have been pondering this- and can't come up with a good rationale.
On large aircraft, where you have significant electrical loads that are
distant from the cockpit, it would make sense to use a relay so that you minimize
voltage drop and/or weight by eliminating long wiring runs. But this doesn't
seem to be the case here. The argument regarding electromagnetic fields near
radios does not hold up since the loads are the same whether switched through
a relay or not.
I guess the bottom line is- There are some VERY smart people building these aircraft.
Surely there is a good reason for the master relay design- I just want
to know what it is?
Blue Skies,
Mike Ice
RV-9, electrical almost complete, just laid up fiberglass skirts for the canopy
last night,
next up: motor mount, install gear legs, then engine
Message 4
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Subject: | Crimp on terminals |
Is it a good idea to "tin" wire ends with a little solder before using crimp
on terminals for D miniature connectors, or not?
Grant Neilson
RV9A, finishing
Message 5
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Subject: | Re: Relay and capacitor info needed |
At 06:36 AM 4/14/2007 +0000, you wrote:
>
>Have a few questions (4) about relays and capacitors to be used on my 914
>Rotax powered Europa:
>
>1) If I use a B+C S704-1 "Sealed" relay for OVP to open and close a yellow
>output wire of the internal generator (mounted on engine side of
>firewall), are the chances good it will not blow apart if I choose to wave
>soar up to 35K with long wings? How about at 18K with intercooled motor
>running hard and temp of relay gets up to 212F?
Use the relay to do AC switching instead of DC switching . . .
>2) If I use a Bosh 75 amp "Vented" SPST relay #75251 from
>www.waytekwire.com on the engine side of the firewall used in parallel
>with the B+C for OVP to disconnect the 22K uF capacitor from my E-Bus.
>Should the service life be reasonable on a vented relay on the engine side
>of the firewall on an airplane stored for the most part in a unheated tin
>hangar? It has a small slit to allow it to vent. (On my design, if
>capacitor shorted it would draw down the E-Bus with no way to sever short
>without 2nd relay. My design addresses failure of battery (opened or dead)
>when attempting in flight restart after soaring)
Why not wire your PM alternator like Z-16 and leave the capacitor
across the battery all the time?
>3) When turning on and off the internal generator, the 75 amp Bosh relay
>will be used to charge up the 22K uF capacitor. Can this relay most like
>give good service charging up the capacitor at least once per flight?
>Could the B+C S704-1 "Sealed" relay most like take the abuse of charging
>up the capacitor at least once per flight and be used in place of the Bosh
>75 amp? (Bosh weighs in at 3.1 oz and has dual contacts)
If you're wired per the latest control philosophies for PM
alternators, the capacitor charges through the battery contactor
which won't be particularly stressed by this activity. The
act of charging the capacitor using the output of the alternator
is current limited by the alternator's dynamics. No inrush
concerns here.
>4) I want to use for pitch trim small "Sealed" Osram 12v 5a relays from
>Digikey pn G6B 2214P US DC12, are the chances good it will not blow apart
>if I choose to wave soar up to 35K with long wings? Will be mounted in
>cockpit.
What kind of trim motors? You're probably fine with MAC/RayAllen
actuators. You could easily go all solid state with these duties
and eliminate the worries entirely. You're not going to "blow them
apart" . . . the risk is that at reduced pressures, the arcing
that inevitably forms between spreading contacts is more severe
and you get reduced service life. I've not tested open relays at
these altitudes . . . our mil-spec products are sealed.
Bob . . .
----------------------------------------
( IF one aspires to be "world class", )
( what ever you do must be exercised )
( EVERY day . . . )
( R. L. Nuckolls III )
----------------------------------------
Message 6
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Subject: | Re: Should 22K uF capacitor be fused? |
At 07:15 AM 4/14/2007 +0000, you wrote:
>
>Hello Bob
>
>I was reading a post you made from 01-2000 about putting a 10 amp fuse on
>the 22k uF capacitor of a Rotax internal generator.
>
>Do you still advocate fusing the capacitor? I plan on using a 22K uF 35V
>with a 105C rating.'
It doesn't hurt but it's also unlikely to
be a big help either. The fault currents that
can flow in a self destructing capacitor can
stay below fuse blowing levels.
Better to treat this capacitor as an expendable
like batteries and tires. Replace it every so often,
probably 3-4 years is fine. Even then, you're sandbagging
a really rare event.
Bob . . .
Message 7
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have attempted to incorporate the new rev 11 rotax alternator system
into my dual alt system, as Mike Gregory suggested. PDF file attached. I
have also incorporated several changes made by list members because they
made too much sense to ignore. BOB, does this give me security in the
air. Thank you all.
Vaughn Teegarden
Europa XS mono, Rotax 914
Message 8
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Subject: | Re: Crimp on terminals |
At 08:53 4/14/2007, you wrote:
><grantneilson@telus.net>
>
>Is it a good idea to "tin" wire ends with a little solder before using crimp
>on terminals for D miniature connectors, or not?
Not only is it not a good idea, it's not even permitted when doing
qualified assembly for JPL/NASA flight equipment. This does assume
proper crimp equipment.
Ron Q.
>Grant Neilson
>RV9A, finishing
Message 9
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At 06:49 AM 4/14/2007 -0400, you wrote:
><rdunhamtn@hotmail.com>
>
>Bob said...
>
>"It's unlikely that anyone on staff at your supplier can discuss
>applications and options with any logic. They're only parroting
>information fed to them by others who are equally un-informed as to how
>you meet your design goals."
>
>How right you are! I called Jabiru USA to ask about the voltage regulator
>they sell and install on their Jabiru engines and aircraft. They could not
>tell me any more about the regulator than "It's solid state." They also
>didn't seem to understand the physics of the PM Dynamo in their engines.
It's difficult for folks who WORK in this environment.
I just got home from delivering a Sandbox session to
engineering professionals from my place of work. Wichita
State lets me use a really nice classroom in the NIAR
building for Saturday morning classes.
These are folks who do not get an opportunity to exercise
the best they know how to do every day and it gets away
from you. We did a refresher course this morning on
DC motor characteristics that was well received. My
chief scientist gives me feedback on these efforts and
he has enthusiastically supported and attended the
classes since day-one.
>After looking at their wiring in the few planes under construction, I
>concluded they could use a 'Connection Seminar! But, I kept my mouth shut.
>I was there to learn from them. And it was a good seminar in all other
>respects.
It easy to blow off any need for knowing more about
things that you don't understand or are not interested
in. If I were selling that hardware, I have it apart
and certainly have schematics to refer to. It may not
be mortal sin to sell stuff you don't understand and
cannot explain . . . but it's not a venial sin either.
Bob . . .
----------------------------------------
( IF one aspires to be "world class", )
( what ever you do must be exercised )
( EVERY day . . . )
( R. L. Nuckolls III )
----------------------------------------
Message 10
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Hi all you people who prabably have functioning brain cells left. Here
is my message again with the proper heading. It seems that I can't
destinguish between "Z" and "Rev".
I have attempted to incorporate the new rev 11 rotax alternator system
into my dual alt system, as Mike Gregory suggested. PDF file attached. I
have also incorporated several changes made by list members because they
made too much sense to ignore. BOB, does this give me security in the
air. Thank you all.
Vaughn Teegarden
Europa XS mono, Rotax 914
Message 11
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Subject: | Battery insulation |
A friend has a Cherokee 140 with an original battery box beneath the rear seat.
He has replaced the lead acid battery with a 16 AH RG battery. The RG battery
is oriented the same as the lead acid battery had been. To keep the new battery
from flopping around (it is much smaller than the old lead acid one) he inserted
DOW HI (blue board foam) insulation around the four sides. I don't recall
seeing any insulation under or over the battery. My question: Is this insulation
OK or is there a chance that the battery could overheat if under heavy recharge?
The installation looks nice and tidy and is very lightweight, but I'd
like to make sure he is not set up for a problem in flight. Please comment if
you can.
Leo Holler
leoh@gci.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=106925#106925
Message 12
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Subject: | Re: Battery insulation |
Good Afternoon Leo,
Is the RG battery he is using in his Cherokee listed as being approved for
that use?
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 4/14/2007 3:20:30 P.M. Central Daylight Time,
leoh@gci.net writes:
A friend has a Cherokee 140 with an original battery box beneath the rear
seat. He has replaced the lead acid battery with a 16 AH RG battery. The RG
battery is oriented the same as the lead acid battery had been. To keep the new
battery from flopping around (it is much smaller than the old lead acid one)
he inserted DOW HI (blue board foam) insulation around the four sides. I
don't recall seeing any insulation under or over the battery. My question: Is
this insulation OK or is there a chance that the battery could overheat if under
heavy recharge? The installation looks nice and tidy and is very
lightweight, but I'd like to make sure he is not set up for a problem in flight.
Please
comment if you can.
Leo Holler
************************************** See what's free at http://www.aol.com.
Message 13
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Subject: | Re: Relay and capacitor info needed |
Hello Bob
Thx. for the reply. There remains unanswered questions if you don't mind,
I will note below with ****
>>Have a few questions (4) about relays and capacitors to be used on my 914
>>Rotax powered Europa:
>>
>>1) If I use a B+C S704-1 "Sealed" relay for OVP to open and close a yellow
>>output wire of the internal generator (mounted on engine side of
>>firewall), are the chances good it will not blow apart if I choose to wave
>>soar up to 35K with long wings? How about at 18K with intercooled motor
>>running hard and temp of relay gets up to 212F?
>
> Use the relay to do AC switching instead of DC switching . . .
**** The yellow output wire of the Rotax generator is AC. My question has
to do with the internal pressure of the relay blowing apart the sealed
container like a bag of potato chips that will explode at altitude. Do you
think this relay can take the internal pressure of 35K or 18K at 212F
without exploding?
>>2) If I use a Bosh 75 amp "Vented" SPST relay #75251 from
>>www.waytekwire.com on the engine side of the firewall used in parallel
>>with the B+C for OVP to disconnect the 22K uF capacitor from my E-Bus.
>>Should the service life be reasonable on a vented relay on the engine side
>>of the firewall on an airplane stored for the most part in a unheated tin
>>hangar? It has a small slit to allow it to vent. (On my design, if
>>capacitor shorted it would draw down the E-Bus with no way to sever short
>>without 2nd relay. My design addresses failure of battery (opened or dead)
>>when attempting in flight restart after soaring)
>
> Why not wire your PM alternator like Z-16 and leave the capacitor
> across the battery all the time?
**** If running on E-Bus, having a leaking capacitor that can not be
disconnected will defeat much which I desire in my design. I am not using
a Battery contactor, but a Flaming River switch, and turning it off will
not sever the capacitor from the E-Bus. I am willing to accept the extra
complexity to have this extra relay that will disconnect the capacitor
when Rotax generator is turned off either by generator switch or OV. This
is in addition to opening the AC with S704-1 relay. Yes kinda like wearing
suspenders and a belt, but it will accomplish what I desire.
My question is do you think this vented 75 amp relay will provide
reasonable service living on the engine side of the firewall with regard
to condensation causing problems (corrosion/contamination ingress) and or
any other problems that can be associated with a vented relay?
>>3) When turning on and off the internal generator, the 75 amp Bosh relay
>>will be used to charge up the 22K uF capacitor. Can this relay most like
>>give good service charging up the capacitor at least once per flight?
>>Could the B+C S704-1 "Sealed" relay most like take the abuse of charging
>>up the capacitor at least once per flight and be used in place of the Bosh
>>75 amp? (Bosh weighs in at 3.1 oz and has dual contacts)
>
> If you're wired per the latest control philosophies for PM
> alternators, the capacitor charges through the battery contactor
> which won't be particularly stressed by this activity. The
> act of charging the capacitor using the output of the alternator
> is current limited by the alternator's dynamics. No inrush
> concerns here.
**** I am not precise following the latest control philosophies for PM
alternators. I addressed concerns in my design to allow operations from
total loss battery/s for extended soaring, failure of main battery if it
occurred during an inflight restart after soaring, once motor running on a
failed main battery I can get Rotax generator on line to power E-Bus, if
smoke from electric, I can shut down everything and have a fuel pump
running autonomous in seconds.
I want to use either a 75 amp Bosh Relay or a B+C S704-1 to disconnect DC
side from Generator. Do you think the 75 amp relay will hold up charging
the 22K uF capacitor at least once per flight? Do you think a B+C S704-1
relay will hold up charging the 22K uF capacitor at least once per flight?
Again this relay will be the tool used to make a connection and charge the
capacitor.
>>4) I want to use for pitch trim small "Sealed" Osram 12v 5a relays from
>>Digikey pn G6B 2214P US DC12, are the chances good it will not blow apart
>>if I choose to wave soar up to 35K with long wings? Will be mounted in
>>cockpit.
>
> What kind of trim motors? You're probably fine with MAC/RayAllen
> actuators. You could easily go all solid state with these duties
> and eliminate the worries entirely. You're not going to "blow them
> apart" . . . the risk is that at reduced pressures, the arcing
> that inevitably forms between spreading contacts is more severe
> and you get reduced service life. I've not tested open relays at
> these altitudes . . . our mil-spec products are sealed.
**** It is a Ray Allen, I forget the exact model but it is the smallest
one with a indicator. Question is again about blowing them apart because
the internal pressure is higher than the outside pressure at altitude. I
doubt design had in mind aircraft use??? Do you think there is a good
chance that they will not blow apart?
Thx.
Sincerely
Ron Parigoris
Message 14
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Subject: | Re: Crimp on terminals |
Grant,
Tinned wire ends are good for wraping around screws and setting
under screws in terminal blocks but crimp connectors are made to handle
stranded wire. When the wire is crimped it is crushed into one homogenous
mass forcing out air and gauranteeing a corrosion free joint. Also if
using a stiff joint such as a tinned wire or a solid wire the crush
stresses the wire and vibration will likely break the wire,sooner or
later, at the joint. HTH
Larry Mac Donald
lm4@juno.com
Rochester N.Y.
Do not archive
On Sat, 14 Apr 2007 08:53:47 -0700 "Grant Neilson"
<grantneilson@telus.net> writes:
> <grantneilson@telus.net>
>
> Is it a good idea to "tin" wire ends with a little solder before
> using crimp
> on terminals for D miniature connectors, or not?
>
> Grant Neilson
> RV9A, finishing
>
>
>
>
>
>
>
>
Message 15
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Subject: | Re: curious questions |
In the course of helping a friend construct an RV 9 I had the opportunity
to examine the electrical system design. I was puzzled at the use of a
master relay (solenoid) to switch the entire electrical system. A number
of questions occurred to me regarding this design:
The questions: How much amperage draw does the solenoid consume simply
being energized? At what voltage does the Solenoid release? And why this
design?
_________________________________________________________________________
_____
1. I can't say for sure but solonoids of this type usually draw between
700ma and 1A.
2. They don't release. They stay on as long as the master switch is on.
_________________________________________________________________________
_______
It seems to me inserting the master relay (solenoid) into the electrical
system has no benefit and some detriment.
The detriments are: 1. constant draw on battery when energized. 2.
greater complexity. 3. increased weight (all 6 oz of the solenoid) 4.
failure of the complete electrical system if a) the solenoid fails, or b)
if you have alternator failure and voltage drops low enough to allow the
solenoid to not close/open
Consider this. You want to connect a battery to your entire
airplane,except the ignition system on certified acft. This will supply
as much as 60 amps to the acft systems. If you can't disconnect it your
battery will go flat overnight. So what will you use to
connect/disconnect. How about a little 6oz. solonoid and a tiny,
lightweight, 5 amp switch. I think that would be much better than a big
old 50 amp switch in the cockpit along with the heavy cable run to the
switch and then to the main buss. Now consider starting the engine. with
a single wire system , and with any nav equipment left on, when you hit
the starter the 200 to 300 amps that will be pulled from the battery on a
cold day will cause a voltage drop that will finish off your nav
equipment. So what to do ? Run a cable to a Master solonoid and run very
light wires thru the firewall to the master switch. Then run a jumper
cable from the first contact point of the master solonoid to the current
carrying terminal of a second solonoid. The starter solonoid. And from
there to the starter. And then run a couple of very light wires thru the
firewall to a very light starter switch. Save a few lbs.. Save a lot of
panel real eatate. HTH
Larry Mac Donald
lm4@juno.com
Do not archive
Message 16
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The following information may be useful to others.
I got two small alternators, 30 Amp. with internal regulators that stop
generating when the wire that is connected to the ignition is disconnected.
That means I can use the field crowbar circuit to disconnect in an
overvoltage situation. These alternators come from 3 cylinder Kubota diesel
tractors. They are Denso 16678-6402. I use the two alternators on my dual
electrical system.
Rino
Message 17
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Subject: | Re: Battery insulation |
BobsV35B(at)aol.com wrote:
> Good Afternoon Leo,
> Is the RG battery he is using in his Cherokee listed as being approved for
that use?
>
> Happy Skies,
>
> Old Bob
> AKA
> Bob Siegfried
> Ancient Aviator
> Stearman N3977A
> Brookeridge Air Park LL22
> Downers Grove, IL 60516
> 630 985-8503
Bob,
The battery is not approved for the Cherokee but is FAA PMA'd and approved for
many others I'm told. They will need a 337 to finish the install per his AI.
Leo
See what's free at AOL.com (http://www.aol.com?ncid=AOLAOF00020000000503).
> [b]
>
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=106967#106967
Message 18
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Subject: | Re: Battery insulation |
In a message dated 4/14/2007 8:13:28 P.M. Central Daylight Time,
leoh@gci.net writes:
Bob,
The battery is not approved for the Cherokee but is FAA PMA' d and approved
for many others I'm told. They will need a 337 to finish the install per his
AI.
Leo
Thank You Leo,
In the event something leaks, has anyone yet investigated the suitability of
the foam when it gets involved with corrosive gases? May not be considered a
problem, but --- ??
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Air Park LL22
Downers Grove, IL 60516
630 985-8503
************************************** See what's free at http://www.aol.com.
Message 19
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Subject: | Re: Battery insulation |
Leo,
Without regard to FAA regs etc;
Just a guess, I doubt there should be a problem with the battery box stuffed
as described.
If you used a hole saw to punch the foam full of holes the insulating
quality of the foam would be reduced somewhat.
Also the drilled foam would be less resistant to being crushed and therefore
move out of the way reducing the chance of structural damage should the
"overheating" or dying battery begin to expand.
Who knows what would become of the battery in a crash scenario?
Jim in Kelowna
----- Original Message -----
From: "Leo Holler" <leoh@gci.net>
Sent: Saturday, April 14, 2007 1:16 PM
Subject: AeroElectric-List: Battery insulation
>
> A friend has a Cherokee 140 with an original battery box beneath the rear
> seat. He has replaced the lead acid battery with a 16 AH RG battery. The
> RG battery is oriented the same as the lead acid battery had been. To keep
> the new battery from flopping around (it is much smaller than the old lead
> acid one) he inserted DOW HI (blue board foam) insulation around the four
> sides. I don't recall seeing any insulation under or over the battery. My
> question: Is this insulation OK or is there a chance that the battery
> could overheat if under heavy recharge? The installation looks nice and
> tidy and is very lightweight, but I'd like to make sure he is not set up
> for a problem in flight. Please comment if you can.
>
> Leo Holler
> leoh@gci.net
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=106925#106925
>
>
>
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