---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 01/08/13: 9 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:36 AM - Re: Aeroled wiring (Eric M. Jones) 2. 10:02 AM - Lithium batteries redux (Robert L. Nuckolls, III) 3. 10:23 AM - Re: Re: Aeroled wiring (Robert L. Nuckolls, III) 4. 10:50 AM - Narco 11 connector source () 5. 11:35 AM - Re: Substitute Midi Fuse instead of ANL Fuse (Robert L. Nuckolls, III) 6. 11:36 AM - Re: Narco 11 connector source (Robert L. Nuckolls, III) 7. 01:49 PM - Re: Substitute Midi Fuse instead of ANL Fuse (user9253) 8. 02:21 PM - Re: Lithium batteries redux (Robert Borger) 9. 03:43 PM - Re: Lithium batteries redux (Jan de Jong) ________________________________ Message 1 _____________________________________ Time: 06:36:59 AM PST US Subject: AeroElectric-List: Re: Aeroled wiring From: "Eric M. Jones" Being completely ignorant of the Aeroled system and wiring.... Noise in Electrical Circuits 101: 1) Saving a dollar in pcb design often generates problems that take thousands of dollars to solve in the field. (Hard-won wisdom.) 2) In my opinion, using a two layer PCB in a low-noise design is insane, unless it can be proven that it works as well as a 4-or-more layer board. 3) Sharp-edged signals have their place in extremely small, extremely low-power logic, but not in power supplies beyond what is needed to keep the thermal issues under control and the parts' size and cost manageable. 4) Minimize clock traces and clock trace power, and clock signal edges. 5) Control noise at the source. Always. Noise in strobes: Whelen designed their venerable strobe units long ago. The strobe energy was stored in caps right at the beefy master-supply-strobe-sync unit. Today, especially for LEDs the strobe energy is best accumulated right at the discharge point (Supercaps?) to reduce noise issues and wiring size. Power to the strobes should be entirely DC with the sync signal generated by any number of simple means that won't generate an audio tick. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=391799#391799 ________________________________ Message 2 _____________________________________ Time: 10:02:10 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Lithium batteries redux This morning's news included a bit concerning a battery fire in a B787 on the ramp at Boston airport. http://tinyurl.com/bx3ww23 According to Skip Koss (and unlike the Cessna ramp fire in the Citation) this fire appears to have been controlled by individuals both trained and equipped for dealing with a lithium fire. A123 (manufacturer of the cells in the Cessna battery) is shut down in bankruptcy although I understand they've been purchased by a Chinese interest. Folks. I think it's pretty clear that the large energy storage lithium products are not ready for prime time on airplanes. There's a lot of ground based history being made and new product development being conducted which may ultimately evolve into products with aviation-grade failure modes and risks . . . let us wait and see. Sometimes, the best way to drive a nail is with a hammer and the best way to carry a reserve of electrons is with lead-acid. http://tinyurl.com/3atma44 Bob . . . ________________________________ Message 3 _____________________________________ Time: 10:23:06 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Aeroled wiring At 08:35 AM 1/8/2013, you wrote: Being completely ignorant of the Aeroled system and wiring.... Noise in Electrical Circuits 101: 1) Saving a dollar in pcb design often generates problems that take thousands of dollars to solve in the field. (Hard-won wisdom.) 2) In my opinion, using a two layer PCB in a low-noise design is insane, unless it can be proven that it works as well as a 4-or-more layer board. . . . . or has been proven adequate by DO-170/Mil-STD-462 testing. 3) Sharp-edged signals have their place in extremely small, extremely low-power logic, but not in power supplies beyond what is needed to keep the thermal issues under control and the parts' size and cost manageable. 4) Minimize clock traces and clock trace power, and clock signal edges. 5) Control noise at the source. Always. Noise in strobes: Whelen designed their venerable strobe units long ago. The strobe energy was stored in caps right at the beefy master-supply-strobe-sync unit. Today, especially for LEDs the strobe energy is best accumulated right at the discharge point (Supercaps?) to reduce noise issues and wiring size. Power to the strobes should be entirely DC with the sync signal generated by any number of simple means that won't generate an audio tick. It's not yet clear as to the nature of the offending emission. The filter needed for integrating the Luxdrive products addressed a poorly managed radio frequency issue. This spectrum of potential interference IS covered by DO-160, Paragraph 21.3 The 'tick' cited by several writers is probably a conducted, fast rise current transient coming out on the power lines. This is a very low energy event at an audio rate and with imperceptible radio frequency components. DO-160 DOES have a test for SUSCEPTIBILITY to low energy spikes (used to be called the chattering relay test . . . in fact, early bench test fixtures did indeed use a 'buzzing' relay as a noise generator). But it doesn't speak to kind of noise EMISSION that might generate the 'tick'. There are LOTS of devices that generate transients that might 'tick' . . . landing light turn on, pitot heat turn on, landing gear motor inrush, etc. Folks tend to ignore these due to their intermittent, one-time occurrence. But when it happens continuously in sync with repetitive operations like wig-wag or strobe, it's another matter. This is a new condition that has not yet be addressed by codification . . . the manufacturers of guilty product would do well to jump on this and fix it before the bureaucrats decide to step in and help. Bob . . . ________________________________ Message 4 _____________________________________ Time: 10:50:43 AM PST US From: Subject: AeroElectric-List: Narco 11 connector source Does anyone have the part number or a source for the 15 pin connectors on the back of a Narco 11A? I am planning on putting a TKM in the tray but the current connector has broken into pieces. I am hoping I can get one cheaply from Mouser or Digikey or someplace similar. ________________________________ Message 5 _____________________________________ Time: 11:35:46 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Substitute Midi Fuse instead of ANL Fuse At 04:12 PM 1/7/2013, you wrote: A friend of mine, Larry, wants to use a Midi Fuse instead of an ANL to protect the battery and wires from a possible shorted alternator. His Viking engine comes with a 40 amp alternator. The Midi Fuse is physically smaller than the ANL and will take up less room on his crowded firewall. Question 1: Is it OK to use a Midi Fuse for this application? Absolutely. There are several variations on the ANL theme found in all manner of DC power systems that range from the 'fusible link' up to and including the legacy ANL/ANN style current limiters. This would included devices like the Littlefuse MIDI The data sheet you linked was for the BF1 which is closer to a fuse than a current limiter. Compare the specs found here and you'll see that operating times versus current for the BF1 fuse is asymptotic to a value close to its rating while the MIDI is more like a current limiter where the asymptote is much greater than the device rating. http://tinyurl.com/by5qnop None the less all variations on this them are suitable to your task. Question 2: Should a 40 or a 50 amp fuse be used? Keep in mind that the rating of an alternator is for worst case conditions. A cold alternator is capable of significantly more than rated output until it warms up. Hence the condition known as the "B-lead breaker designed to nuisance trip" which describes the use of 60A breakers on 60A alternators on thousands of TC aircraft. You'll notice that the fusing specs for these these Littlefuse BF1 are not as robust as the legacy current limiter. I note that Littlefuse calls these devices 'fuses' as opposed to 'current limiters'. You will note too that the BF1 has a few parts tagged with "Note 3" suggesting that these parts should be used for short circuit protection only . . . more like their MIDI cousins. The short answer is that one would do well to use a substantially larger BF1 FUSE on the 40A machine . . . 70A would not be out of line. A MIDI-50 (almost a current limiter) would be okay too. Bob . . . ________________________________ Message 6 _____________________________________ Time: 11:36:58 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Narco 11 connector source At 12:49 PM 1/8/2013, you wrote: > >Does anyone have the part number or a source for the 15 pin >connectors on the back of a Narco 11A? I am planning on putting a >TKM in the tray but the current connector has broken into pieces. I >am hoping I can get one cheaply from Mouser or Digikey or someplace similar. Do you have the pieces? Can you send me a photo of the pieces and a view looking into the back of the radio? Bob . . . ________________________________ Message 7 _____________________________________ Time: 01:49:16 PM PST US Subject: AeroElectric-List: Re: Substitute Midi Fuse instead of ANL Fuse From: "user9253" Thanks for the info, Bob. I will pass it on to Larry. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=391840#391840 ________________________________ Message 8 _____________________________________ Time: 02:21:23 PM PST US Subject: Re: AeroElectric-List: Lithium batteries redux From: Robert Borger Bob, You may very well be correct, but I've gone out on a limb that I trust will support me and the aircraft. I have purchased and installed an Aerovoltz 12 Cell EV02 LiFePo battery in my Europa. The LiFePo battery is not supposed to be the fire hazard that the LiFe battery is. It is amazingly small and light. About 12 lbs lighter than the Odyssey it replaces. I would not have done this had my Rotax 914 still been electric dependent with two electric fuel pumps. about 2 years ago I replaced one of the electric pumps with an engine driven, mechanical pump so the engine will continue to operate should the electrics go totally dead. So far, in 2 hours of testing on the ground and 1 hour in the air, all seems well. It spins the Rotax on startup just like the Odyessy. I purchased the special charger that will do fast, 5A, charge; slow. 2A, charge; maintenance, .1A, charge/float and cell balancing. I have not done any time/power testing. I need to see how long it will run the radio, transponder and GRT EIS 4000 and then test with only the radio and EIS. When this is done, I will report the results. The seller of the battery did warn not to discharge below 9v as that would probably permanently damage the battery. And if discharged to below 11 volts, it must be recharged in the cell balance mode. Isn't this one reason why we call it Experimental? Blue skies & tailwinds, Bob Borger Europa XS Tri, Rotax 914, Airmaster C/S Prop. Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP 3705 Lynchburg Dr. Corinth, TX 76208-5331 Cel: 817-992-1117 rlborger@mac.com On Jan 8, 2013, at 12:00 PM, "Robert L. Nuckolls, III" wrote: This morning's news included a bit concerning a battery fire in a B787 on the ramp at Boston airport. http://tinyurl.com/bx3ww23 According to Skip Koss (and unlike the Cessna ramp fire in the Citation) this fire appears to have been controlled by individuals both trained and equipped for dealing with a lithium fire. A123 (manufacturer of the cells in the Cessna battery) is shut down in bankruptcy although I understand they've been purchased by a Chinese interest. Folks. I think it's pretty clear that the large energy storage lithium products are not ready for prime time on airplanes. There's a lot of ground based history being made and new product development being conducted which may ultimately evolve into products with aviation-grade failure modes and risks . . . let us wait and see. Sometimes, the best way to drive a nail is with a hammer and the best way to carry a reserve of electrons is with lead-acid. http://tinyurl.com/3atma44 Bob . . . ________________________________ Message 9 _____________________________________ Time: 03:43:23 PM PST US From: Jan de Jong Subject: Re: AeroElectric-List: Lithium batteries redux My assessment sofar (FWIW). The problem with LiFePO4 batteries is that they do not self-balance well. And the 4 cells are not reliably identical. The result is as follows. You can either keep the cells balanced in the charged state, meaning that none of the four will ever go over 4 volts when the battery is charged at 14.4 V or so. Or you can keep them balanced in the discharged state, meaning that none of the four will ever be driven below 2 volts when the battery is discharged to below 12 volts. You cannot have both without sophisticated power electronics. In our type of use we keep the battery balanced in the charged state. The danger then lies in deep discharging. I will only use LiFePO4 if I can have a battery alarm that goes off when any one of the 4 cells goes below 2 volts (when discharging) or above 4 volts (when charging). And an alternative source of backup energy if either occurs. I would like to know in the meantime what level of battery monitoring is done on the accident Cessnas and Dreamliners... Jan de Jong On 1/8/2013 11:20 PM, Robert Borger wrote: > > Bob, > > You may very well be correct, but I've gone out on a limb that I trust will support me and the aircraft. > > I have purchased and installed an Aerovoltz 12 Cell EV02 LiFePo battery in my Europa. The LiFePo battery is not supposed to be the fire hazard that the LiFe battery is. It is amazingly small and light. About 12 lbs lighter than the Odyssey it replaces. > > I would not have done this had my Rotax 914 still been electric dependent with two electric fuel pumps. about 2 years ago I replaced one of the electric pumps with an engine driven, mechanical pump so the engine will continue to operate should the electrics go totally dead. > > So far, in 2 hours of testing on the ground and 1 hour in the air, all seems well. It spins the Rotax on startup just like the Odyessy. I purchased the special charger that will do fast, 5A, charge; slow. 2A, charge; maintenance, .1A, charge/float and cell balancing. I have not done any time/power testing. I need to see how long it will run the radio, transponder and GRT EIS 4000 and then test with only the radio and EIS. When this is done, I will report the results. > > The seller of the battery did warn not to discharge below 9v as that would probably permanently damage the battery. And if discharged to below 11 volts, it must be recharged in the cell balance mode. > > Isn't this one reason why we call it Experimental? > > Blue skies & tailwinds, > Bob Borger > Europa XS Tri, Rotax 914, Airmaster C/S Prop. > Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP > 3705 Lynchburg Dr. > Corinth, TX 76208-5331 > Cel: 817-992-1117 > rlborger@mac.com > > On Jan 8, 2013, at 12:00 PM, "Robert L. Nuckolls, III" wrote: > > > This morning's news included a bit concerning > a battery fire in a B787 on the ramp at Boston > airport. > > http://tinyurl.com/bx3ww23 > > According to Skip Koss (and unlike the > Cessna ramp fire in the Citation) this fire appears > to have been controlled by individuals both trained > and equipped for dealing with a lithium fire. > > A123 (manufacturer of the cells in the Cessna > battery) is shut down in bankruptcy although > I understand they've been purchased by a Chinese > interest. > > Folks. I think it's pretty clear that the large > energy storage lithium products are not ready for > prime time on airplanes. There's a lot of ground > based history being made and new product development > being conducted which may ultimately evolve into > products with aviation-grade failure modes and risks . . . > let us wait and see. > > Sometimes, the best way to drive a nail is with > a hammer and the best way to carry a reserve of > electrons is with lead-acid. > > http://tinyurl.com/3atma44 > > > Bob . . . > > ------------------------------------------------------------------------------------- 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.