---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 04/20/08: 18 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:00 AM - Backup Batteries (Chuck Jensen) 2. 05:46 AM - Re: Re: A Bit of Help, Please (Robert L. Nuckolls, III) 3. 05:52 AM - Re: Backup Batteries (Robert L. Nuckolls, III) 4. 05:57 AM - Questions on avionics () 5. 06:04 AM - Re: Grommets (Eric M. Jones) 6. 06:04 AM - Re: pinout for Softcom ATC-P intercom?? (Robert L. Nuckolls, III) 7. 06:50 AM - Re: Re: Grommets (Ken) 8. 09:05 AM - LED Landing Lights, was: A Bit of Help, Please (D Fritz) 9. 10:13 AM - Grommets (Dennis Johnson) 10. 10:39 AM - Garmin 250XL problem (N81JG) 11. 01:36 PM - Re: Garmin 250XL problem (Tim Andres) 12. 05:04 PM - Dual alternator single shunt (Ron Shannon) 13. 05:16 PM - Re: Dual alternator single shunt (MartinErni@aol.com) 14. 05:51 PM - Re: Dual alternator single shunt (Ron Shannon) 15. 06:01 PM - Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 (Lee Logan) 16. 06:30 PM - Re: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 (Dale Ensing) 17. 07:10 PM - Re: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 (Ron Shannon) 18. 07:46 PM - why a battery bus? [was: Digest....] (Ron Shannon) ________________________________ Message 1 _____________________________________ Time: 04:00:02 AM PST US Subject: AeroElectric-List: Backup Batteries From: "Chuck Jensen" Curious question about the backup battery for a Mid-Continental LifeSaver attitude indicator with back up battery. While the back up battery is rated for one hour, actual flight testing, when the battery is new, showed that a duration of nearly two hours were available, though the battery seems to die after about three years---disappointing for a +$100 battery. By way of configuration, the backup battery is fed by plane power to keep charged. If the plane electrical power is lost, the AI reverts to the battery to keep its gyro spinning--all very conventional. The question is "is there a credible scenario whereby the electrical power in the plane is not only lost, but actually becomes an "electron sink" and pulls those lifesaving electrons out of the backup battery for the AI, shortening its useful duration? Is this incredible? Is diode isolation needed on the electrical lines to the backup battery? Chuck Velo XLRG ________________________________ Message 2 _____________________________________ Time: 05:46:26 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: A Bit of Help, Please >Subject: AeroElectric-List: Re: A Bit of Help, Please >To: aeroelectric-list@matronics.com > > >Bob, >Thanks for your robust reply. Very helpful. >My intention is to prevent reverse current flow in certain conditions. >I connected the zener diodes in line where needed and did a test of the >system and the diodes did stop the reverse flow of current - as >desired. My concern was that the selected diodes (RS INT4742A - RS part >number 276-563) may not be robust enough to stop the 0.9 Amp current over >the long term. That's what I understood. I was mystified by the use of a zener diode. These will "stop reverse flow" only if the voltage remains below the rating at which reverse flow is desired and expected . . . in the case of the 1N4742, 12 volts. The "ratings" numbers for these devices are given in there reverse current flow mode of operation where they dissipate higher power for the same current flow. Since this package is generally good for about 1W of dissipation, their max reverse current should be limited to about 1w/12v = 0.08 amps. The 0.02 amps you cited was the "test current" at which the 12v regulation accuracy was given . . . not the operating current where the current is dissipation limited. You're using these devices in their forward conduction mode where voltage drop is not related to the zener voltage rating of the device, i.e. 12v but the forward conduction rating which is on the same order as the ordinary silicon diode rectifier of about 0.8 volts. Here the same dissipation limits apply . . . but to get 1w of heat out of it in the forward mode, you can now force 1.2a through the device. MUCH larger than any of the reverse current ratings given in the 1N4742 data sheet . . . because folks are generally expect to use theses as reverse current regulators, not forward current power steering devices. http://en.wikipedia.org/wiki/Zener_diode This is why the 1N4742 didn't smoke during your extended bench test . . . you were not using it in the manner described in the data sheets hence non-hazardous dissipated power at higher than "rated" currents. >I may as well insert the correct diodes now rather than redo the work at a >later time. So, it sounds like I should change the diodes to another type >or another rating. Correct? Perhaps the 1N5400 series would be best. The significance of my earlier posting was that mis-application of the zener as a power steering device was marginally satisfactory given that voltages in your system are expected to exceed the 12v rating of the device whereupon some amount of reverse current may flow under conditions where you don't want it to happen. If you picked a zener that was larger, say 16v or even higher, then it could be expected to function as you intended even if it wasn't exactly the right part for the job. The silicon rectifier also has a voltage rating stated as a limit. See: http://www.diodes.com/datasheets/ds28002.pdf Note that these little critters are the same physical size as the 1N4742 but have voltage limits ranging from 50 to 1000v. Any of these devices could be used in your application. I suggested the 5400 series devices be considered also: http://www.diodes.com/datasheets/ds28007.pdf These to are offered in the same ranges of voltage limits as the 4000 series devices and while electrically much larger than you need in this particular case, there's no great transgression in using such devices at much lower levels than their rated limits. In this case, I favor the 5400 series devices for their mechanical robustness. Larger package, larger leadwires, much easier to work with in these situations and less likely to be damaged in service due to handling. I think you got sucked into the 12v zener selection due to a mis-understanding of its rating as being "appropriate" to your 14v airplane. The problem was that zeners are not intended for or generally used as reverse power blocking devices. The silicon rectifiers come with lots larger voltage LIMIT ratings so while much larger than the system voltage of your aircraft, they are not being mis-applied by using say a 600v device in your 14v airplane. So yes, my recommendation is that you avail yourself of Radio Shack's standard inventory and substitute any one of the 5400 series devices for the 1N4742 in the application you've described. Bob . . . ________________________________ Message 3 _____________________________________ Time: 05:52:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Backup Batteries At 06:52 AM 4/20/2008 -0400, you wrote: > >Curious question about the backup battery for a Mid-Continental LifeSaver >attitude indicator with back up battery. While the back up battery is >rated for one hour, actual flight testing, when the battery is new, showed >that a duration of nearly two hours were available, though the battery >seems to die after about three years---disappointing for a +$100 battery. They're doing the same thing you would be expected to to when sizing your e-bus loads in relation to the size and condition of you ship's battery. The 1 hour endurance rating should be up to and including the service life limit of the battery . . . which in this case is the 3 years that you've cited. New out of the box, would would expect the battery's capacity to be higher than at end of life. >By way of configuration, the backup battery is fed by plane power to keep >charged. If the plane electrical power is lost, the AI reverts to the >battery to keep its gyro spinning--all very conventional. The question is >"is there a credible scenario whereby the electrical power in the plane is >not only lost, but actually becomes an "electron sink" and pulls those >lifesaving electrons out of the backup battery for the AI, shortening its >useful duration? Is this incredible? Is diode isolation needed on the >electrical lines to the backup battery? Any designer worth his/her salary would have included reverse power isolation as part of the product. I.e, all system failure modes should have been addressed in the design such that if you install per the manufacturer's instructions, it will perform as advertised. So yes, your question is certainly valid . . . for which the manufacturer of the product should answer, "no sweat . . . that's built in." It's unfortunate that internal backup batteries tend to be pricey. The attention paid to selection, installation and maintenance of a backup battery is more rigorous than for the ship's battery that at least gets "tested" for internal resistance every flight cycle when you crank the engine. But if your project has an e-bus, then you've done the planning and provided for an un-interruptible power source. Stacking another $100 battery on top of this may not offer a good return on investment. Bob . . . ________________________________ Message 4 _____________________________________ Time: 05:57:35 AM PST US From: Subject: AeroElectric-List: Questions on avionics 4/20/2008 Hello Ira, You wrote: 1) "This is just the performance test." I assume that you mean the testing required every two years by FAR Sec's 91.411 and 91.413 as appropriate. I apologize for not having made the situation clearer to you. I also wanted the testing required by 91.411 / 91.413 to sufficiently meet the requirements of 91.217 (b) so that one could operate with an EFIS that contained the only atitude encoder in the airplane and that altitude encoder would be non TSO'd. So I wrote to FAA HQ asking that question. Here is an exact quote of their response: "Your letter posed the following questions: 1. If an amateur built experimental aircraft has an installed TSO'd ATC transponder as required by Title 14 Code of Federal Regulations (14 CFR) section 91.215, but a non-TSO'd altitude encoder and the installation has passed the test and inspection requirements of 14 CFR sections 91.411 and 91.413 within the preceding 24 calendar months, does the installation meet the requirements of 14 CFR section 91.217(b), and therefore make that installation acceptable for IFR operations? 2. If the answer to question one is No, can you please tell me why? The answer to question one is "No." The testing required to show the transmitted altitude data corresponds within 125 feet (on a 95 percent probability basis) is more rigorous than the requirements referenced in 14 CFR sections 91.411, 91.413, and 14 CFR, part 43 appendices E and F. The tests required by 14 CFR part 43 appendix E(c) measure the automatic pressure altitude at a sufficient number of test points to ensure the altitude reporting equipment performs its intended function. Title 14 CFR section 91.217 paragraphs (b) and (c), state that pressure altitude reporting equipment must be tested and calibrated to transmit altitude data correspondence within stated specifications; or, the altimeters and digitizers must meet the standards in TSO-C10B and TSO-C88, respectively. Should the owner/operator elect to exhibit compliance with tests and calibration provided in 14 CFR section 91.217(b), a test method would need to be developed that ensures the transmitted data corresponds within 125 feet of the indicated altitudes from sea level to the maximum operating altitude of the aircraft on a 95 percent probability basis. This testing also needs to ensure the performance characteristics of the equipment are not impacted when subjected to environmental conditions (voltage fluctuations temperature, vibration, etc.) which may be encountered in airborne operations. Completed tests and calibration results should be maintained in the aircraft records. Thank you for your interest in aviation safety." So you can see that FAA HQ does not agree with our wishes. Further you can see that an amateur builder attempting to comply with the FAA HQ version of the testing requirements of 91.217 (b) in order to avoid having a TSO'd altitude encoder installed in his airplane would have a very difficult / impossible time doing so. 2) "It says nothing about TSO." That is correct. The TSO part is found in 91.217 (c). So the person mentioned in the beginning of 91.217 is given two choices -- he can comply with either 91.217 (b) or (c). 3) "Part 21 and 23 do not apply to owner built aircraft with special airworthiness certificates." Basically true, but not specifically relevant to this discussion unless the builder would try to use a non TSO'd altitude encoder by requesting approval to deviate from TSO C-88b and its references in accordance with the procedures of FAR Sec 21.609 -- not a trivial task. Please let me know if I have not adequately described the situation. 'OC' Says: "The best investment we can make is the effort to gather and understand knowledge." ----------------------------------------------- Time: 07:01:52 AM PST US Subject: AeroElectric-List: Re: Questions on avionics From: "rampil" Again, back to 91.217 (b): (b) Unless, as installed, that equipment was tested and calibrated to transmit altitude data corresponding within 125 feet (on a 95 percent probability basis) of the indicated or calibrated datum of the altimeter normally used to maintain flight altitude, with that altimeter referenced to 29.92 inches of mercury for altitudes from sea level to the maximum operating altitude of the aircraft; or This is just the performance test. It says nothing about TSO. Part 21 and 23 do not apply to owner built aircraft with special airworthiness certificates -------- Ira N224XS ________________________________ Message 5 _____________________________________ Time: 06:04:39 AM PST US Subject: AeroElectric-List: Re: Grommets From: "Eric M. Jones" Holes and temperature had nothing to do with it. Extract from: http://www.alliedrubber.com/Gasket/SBRRubber.cfm.htm Neoprene is known for its resistance to oil, gasoline, sunlight, ozone and oxidation; however, there are other polymers that have better resistance to these same elements. Neoprene's most important advantage is its ability to combine these properties moderately into one all-purpose polymer. Resistance to corrosive actions of chemicals is good. Neoprene exhibits resilience, tensile strength, tear resistance and dynamic properties; abrasion resistance and compression set properties. COLOR Black DURO 40,50,60,70,80 TENSILE900 ELONGATION300% TEMP-20F to 170F OIL RESIST Good Nitrile's (Buna-N) resistance to the more aromatic distillates of petroleum is better than neoprene, and it exhibits excellent resistance to mineral and vegetable oils, but relatively poor resistance to the swelling action of oxygenated solvents such as acetone and the ketones. Resistance to heat aging is good. Nitrile exhibits good resilience, low permanent set, good abrasion resistance and some ozone resistance. Tear resistance is inferior to natural rubber. Nitrile accommodates applications where oils and heat are prevalent. COLOR Black/ White DURO 60 TENSILE300 ELONGATION900% TEMP-20F to 170F OIL RESIST. Good SBR: Certain types of SBR offer improved wear resistance in tire treads while others provide better low temperature flexibility. SBR has similar resistance to solvents and chemicals as natural rubber and it can be successfully bonded to a wide range of materials. When exposed to petroleum derivatives, the performance of this rubber is inferior to many other synthetics. Red SBR rubber is popular for use as a gasket in low pressure applications such as washers and gaskets for the heating and plumbing trades. COLOR Red/Black DURO 75 TENSILE400 ELONGATION150% TEMP-29F to 170F OIL RESIST. None [This should be a clue] Summary. SBR should NEVER be used for grommets near petroleum vapors, oils or solvents. General advice: It is always a surprise when modern materials fail. Companies spend a lot of money to prevent problems like this, and even materials "not recommended" for an application usually don't fail quickly. But beware inexpensive materials made for specific applications not-your-own. Surprises happen. Things break. "In times of rapid change, experience could be your worst enemy." ---Jean Paul Getty -------- 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=177963#177963 ________________________________ Message 6 _____________________________________ Time: 06:04:39 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: pinout for Softcom ATC-P intercom?? At 04:01 PM 4/18/2008 -0700, you wrote: > > In the mean time, if anyone has the documentation > > covering any version of a Softcom product and could > > either produce a good scan or loan it to me for scanning, > > I'd be happy to add the data to the library. > >Bob, > >Attached are scans of a photocopy of a Softcomm intercom schematic. >It's a bit hazy but quite readable if one prints it at full resolution >and tapes both halves together. > >I've already sent a copy to the original requestor. Thank's Joe, I've worked on it a bit in Photoshop and enhanced the readability a tad. It has been posted to: http://www.aeroelectric.com/Installation_Data/ATC-2P_Schematic.gif Bob . . . ________________________________ Message 7 _____________________________________ Time: 06:50:02 AM PST US From: Ken Subject: Re: AeroElectric-List: Re: Grommets Another product that may be suitable is the plastic snap bushings such as Spruce 04-05730. I never liked putting soft grommets from any source in very thin metal. Ken Jeff Page wrote: > > Two of you both thought my grommet problem so absurd that it must be a > prank. > I wish that were true, but my T hangar is locked. > They were exposed only to cold air, darkness, time and my installation. > When I get to the hangar next, i will be taking a close look at all of > them, to see if the ones remaining are partly torn, or if some of them > are perfectly intact. > I will also try to do some tests with some still in the box to see if I > can tear them like that. > Sure is weird though. We install grommets to protect the wires, so they > should be tougher than the insulation. > > Jeff > >> Are you sure someone didn't cut them off, just to play a mind game with >> you?? >> >> Roger > >>> Just a guess but exposure to solvents could breakdown SBR. I cannot >>> imagine that hole size alone is the issue. >> I will chime in and comment.... This is really hard to believe they spli >> t all by themselves. Are you sure someone didn't remove them and split t >> hem with a razor and them drop them on the floor as a joke/ prank etc... >> >> Ben Haas > ________________________________ Message 8 _____________________________________ Time: 09:05:53 AM PST US From: D Fritz Subject: LED Landing Lights, was: AeroElectric-List: A Bit of Help, Please Stan, I've been watching the development of Landing Lights over the last several years as I build my Velocity. It used to be the cost of flying was enough to rationalize keeping on building rather than actually finishing and taking the plane out of the garage. Now it seems the advances in LED technology may be a new way to rationalize! I'm curious if you've lit these up yet and can give us an impression of how well they light compared to the other technologies out there (filament, halogen, HID, etc.). Can you give us a quick user report? What model are you using? Thanks, Dan --------------------------------- Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. ________________________________ Message 9 _____________________________________ Time: 10:13:41 AM PST US From: "Dennis Johnson" Subject: AeroElectric-List: Grommets Hi Jeff, I just can't imagine any circumstance where expansion/contraction could cut a grommet completely in two. It might cut a grommet mostly in half, but it seems like at some point as the grommet failed, the pressure on it would be released and the grommet would stop failing and remain in place. To find them lying on the floor, cut in half, is really baffling. But I'm interested in hearing your conclusion, because I always enjoy learning something new. I wonder if the grommets were manufactured by bonding two pieces together and the grommets failed by splitting apart on the bond line due to a manufacturing defect? Dennis Johnson ________________________________ Message 10 ____________________________________ Time: 10:39:57 AM PST US From: N81JG Subject: AeroElectric-List: Garmin 250XL problem I have a VariEze with a Garmin 250XL GPS/COM. I accidentally shut off the master while flying and because of my B&C 8 amp. permanent magnet alternator I continued to feed power to the buss until I rolled out on landing. At that point the instruments showed intermittent low voltage and were flickering and cutting out. I discover the reason and turned the master back on. The next flight my 250XL began to flick off and back on in a split second several times at regular 4-5 min. intervals. It continued to work fine as it was on, but the GPS had to reboot each time. It appears that I have damaged some internal component with the low voltage episode. Does anyone know if this can be fixed easily or am I looking at a major circuit change-out? John Greaves VariEze N81JG Redding, CA ________________________________ Message 11 ____________________________________ Time: 01:36:44 PM PST US From: "Tim Andres" Subject: RE: AeroElectric-List: Garmin 250XL problem Hi John, Tim In cottonwood (Cozy builder.) Those radios have two electrical feeds. I would pull the radio from the tray, find the pinout from the install manual or elsewhere and then check for continuous power to each feed as you move the harness around from the back side. I think I have a pinout for the 300 XL in a hanger near you if you need it. I bet they are the same. Also check the ground wire the same way. There is also a chance it's the connector in the tray and you can clean those contacts with electrical cleaner while you have it out. I'm no expert but I am pretty handy with this sort of thing, and I'm off the next 3 days if you need any help. I'm just guessing but I bet the radio is fine and it's in the tray connector or the install somewhere, probably just a coincidence it came up after your last flight. Tim Andres 347 6138 _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of N81JG Sent: Sunday, April 20, 2008 10:34 AM Subject: AeroElectric-List: Garmin 250XL problem I have a VariEze with a Garmin 250XL GPS/COM. I accidentally shut off the master while flying and because of my B&C 8 amp. permanent magnet alternator I continued to feed power to the buss until I rolled out on landing. At that point the instruments showed intermittent low voltage and were flickering and cutting out. I discover the reason and turned the master back on. The next flight my 250XL began to flick off and back on in a split second several times at regular 4-5 min. intervals. It continued to work fine as it was on, but the GPS had to reboot each time. It appears that I have damaged some internal component with the low voltage episode. Does anyone know if this can be fixed easily or am I looking at a major circuit change-out? John Greaves VariEze N81JG Redding, CA _____ Get the MapQuest Toolbar, Maps, Traffic, Directions & More! ________________________________ Message 12 ____________________________________ Time: 05:04:19 PM PST US From: "Ron Shannon" Subject: AeroElectric-List: Dual alternator single shunt My Murphy Rebel is going together with a slightly modified dual alternator, single battery Z-12 design. The primary alternator is the Jabiru 3300's integral 20A PM alternator. The second, backup only alternator is a manually switched B&C SD-20S. Except during very brief, momentary, preflight test switching perhaps, the two alternators will probably never be ON simultaneously. Due to various challenges, I'd like to use just one ammeter shunt to read output from both alternators, whichever is in use. However, that would require the shunt to be located downstream of the two independent ANL/fusible links, instead of upstream from the ANL/fusible links as shown in Z-12. It appears to me there would be no significant electrical difference in having a single shunt downstream from the two ANL/fusible's compared to two shunts being upstream, as long as the single downstream shunt is big enough to take the output of both alternators if need be. Is that correct, or am I missing something? Ron Murphy Rebel / Jabiru 3300 http://n254mr.com "wiring the panel and FWF" ________________________________ Message 13 ____________________________________ Time: 05:16:00 PM PST US From: MartinErni@aol.com Subject: Re: AeroElectric-List: Dual alternator single shunt Ron, I found it easier to place the shunt next to my common ground block that goes to both batteries. Earnest In a message dated 4/20/2008 8:06:31 P.M. Eastern Daylight Time, rshannon@CRUZCOM.COM writes: My Murphy Rebel is going together with a slightly modified dual alternator, single battery Z-12 design. The primary alternator is the Jabiru 3300's integral 20A PM alternator. The second, backup only alternator is a manually switched B&C SD-20S. Except during very brief, momentary, preflight test switching perhaps, the two alternators will probably never be ON simultaneously. Due to various challenges, I'd like to use just one ammeter shunt to read output from both alternators, whichever is in use. However, that would require the shunt to be located downstream of the two independent ANL/fusible links, instead of upstream from the ANL/fusible links as shown in Z-12. It appears to me there would be no significant electrical difference in having a single shunt downstream from the two ANL/fusible's compared to two shunts being upstream, as long as the single downstream shunt is big enough to take the output of both alternators if need be. Is that correct, or am I missing something? Ron Murphy Rebel / Jabiru 3300 _http://n254mr.com_ (http://n254mr.com/) "wiring the panel and FWF" (http://www.matronics.com/Navigator?AeroElectric-List) (http://www.matronics.com/contribution) **************Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos. (http://autos.aol.com/used?NCID=aolcmp00300000002851) ________________________________ Message 14 ____________________________________ Time: 05:51:57 PM PST US From: "Ron Shannon" Subject: Re: AeroElectric-List: Dual alternator single shunt Thanks for the input. Physically, that's roughly where my shunt will be too, on the FW about 8" or less from the FW ground stud, contactors, battery, etc. (Only one battery here.) I'm just trolling the group wisdom to confirm I'm not creating some unanticipated electrical risk with a single shunt downstream from the two alternators' ANLs. Ron On Sun, Apr 20, 2008 at 5:09 PM, wrote: > Ron, > I found it easier to place the shunt next to my common ground block > that goes to both batteries. > Earnest > ________________________________ Message 15 ____________________________________ Time: 06:01:18 PM PST US From: "Lee Logan" Subject: AeroElectric-List: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 I am in the process of completing the wiring design/effort on my homebuilt F1 Rocket and am "planning" on not using a battery bus, just a main and endurance buses. I'm using Z-13/8 (conventional mags), but don't see a need for a "keep alive" circuit with my avionics suite (not do I need power for an electronic ignition system). I see that other builders have put all sorts of things on their battery bus, such as flaps, clocks, etc. Since I may be missing something here, I'm asking: What does the "List" think ought to be on a "modern" battery bus and what rationale is commonly used to justify those selections, please... Regards, Lee... ________________________________ Message 16 ____________________________________ Time: 06:30:44 PM PST US From: "Dale Ensing" Subject: Re: AeroElectric-List: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 I have a small battery bus for the 'keep alive' for the clock in my engine monitor and for a 12 voltv cig. lighter outlet which I use for the Battery Minder to maintain the battery in the hangar and accesories like my XM radio when flying. Happy with that set up. Dale Ensing ----- Original Message ----- From: Lee Logan To: aeroelectric-list@matronics.com Sent: Sunday, April 20, 2008 8:58 PM Subject: AeroElectric-List: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 I am in the process of completing the wiring design/effort on my homebuilt F1 Rocket and am "planning" on not using a battery bus, just a main and endurance buses. I'm using Z-13/8 (conventional mags), but don't see a need for a "keep alive" circuit with my avionics suite (not do I need power for an electronic ignition system). I see that other builders have put all sorts of things on their battery bus, such as flaps, clocks, etc. Since I may be missing something here, I'm asking: What does the "List" think ought to be on a "modern" battery bus and what rationale is commonly used to justify those selections, please... Regards, Lee... ________________________________ Message 17 ____________________________________ Time: 07:10:21 PM PST US From: "Ron Shannon" Subject: Re: AeroElectric-List: Re: AeroElectric-List Digest: 10 Msgs - 04/19/08 My blade fuse-style battery bus has these fused circuits: 1) cabin dome lights 2) the N/O oil pressure switch which feeds the Hobbes meter 3) E-Bus alternate feed fuse 4) low amperage (15A) ground power which goes to the battery, of course 5) power for the over-voltage panel light so if everything suddenly goes dark due to an over voltage trip, I'll still have a clue what happened. Any of those fuses could be handled by an inline fuse. I prefer having them securely mounted and organized on a fuse block where I can easily get to them. I have one more slot in the block, and will probably find something else to go there. Ron ________________________________ Message 18 ____________________________________ Time: 07:46:46 PM PST US From: "Ron Shannon" Subject: AeroElectric-List: why a battery bus? [was: Digest....] Correction: There is no # 5. The alternator warn light is on the main bus. Don't know what/if I was thinking. My blade fuse-style battery bus has these fused circuits: > > 1) cabin dome lights > 2) the N/O oil pressure switch which feeds the Hobbes meter > 3) E-Bus alternate feed fuse > 4) low amperage (15A) ground power which goes to the battery, of course > 5) power for the over-voltage panel light so if everything suddenly goes > dark due to an over voltage trip, I'll still have a clue what happened. > > Any of those fuses could be handled by an inline fuse. I prefer having > them securely mounted and organized on a fuse block where I can easily get > to them. I have one more slot in the block, and will probably find something > else to go there. > > Ron > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.