---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 08/18/14: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:21 AM - Re: Z-19 Function (Justin Jones) 2. 03:38 AM - Re: Z-19 Function (Justin Jones) 3. 07:00 AM - Re: Z-19 Function (Robert L. Nuckolls, III) 4. 10:11 AM - Re: Z-19 Function (Ken Ryan) 5. 10:36 AM - Re: Z-19 Function (Justin Jones) 6. 10:42 AM - Re: Z-19 Function (Justin Jones) 7. 11:50 AM - Re: Z-19 Function (Jeff Luckey) 8. 03:26 PM - Re: Z-19 Function (Robert L. Nuckolls, III) 9. 07:44 PM - Real life lessons in wire ratings . . . (Robert L. Nuckolls, III) 10. 07:52 PM - Dynon D-180 & flickering LEDs (user9253) ________________________________ Message 1 _____________________________________ Time: 03:21:13 AM PST US Subject: Re: AeroElectric-List: Z-19 Function From: Justin Jones Thanks fit the input Jeff. I appreciate it. I like the way redundancy in the system you drew. You are correct that a single 10A breaker for both coils is a single point o f failure and I don't like it. If a 4-diode rectifier were used with an inpu t from both battery buses, it would solve the issue. Then a single breaker w ould be powering it them from 2 different power sources. On Aug 17, 2014, at 20:06, Jeff Luckey wrote: > Justin, > > ... I have also learned that a single 10A breaker feeds both coils. I wo uld think the 4-diode rectifier with power from the engine battery bus and t he main battery bus would solve the single-point of failure issue with a sin gle power source... > > Without looking a schematic it is difficult to get a clear picture of what you are describing but a single breaker for both coils? Is that not the de finition of a single point of failure? > > > ... I feel that with a dual battery system and a way to isolate the batte ries from each other during flight, a higher level of safety is achieved. > > Agree. > > > ... The pilot would simply isolate the batteries and shut off all items t hat are drawing a load from that battery bus. .... > > The drawing that I posted yesterday does the isolation you are talking abo ut but it does so automatically without any interruption of current flow and requires no pilot interaction. > > > The challenge is to engineer a reliable and redundant 12V system that will allow for safe and reliable operation regardless of individual component, c omplete bus, or even power source failure. > > This wheel has been invented many times over. Between Bob N's Z drawing(s ) and the one I posted, you should be able accomplish your goals. > > > -Jeff > > > On Sunday, August 17, 2014 8:37 PM, Justin Jones wrote: > > > Here is the link to the downloadable instruction manual. http://flyefii.co m/customer_projects/EFII_Ignition_Instruction_sheet_rev9-13.pdf > > There is a Dual ECU addendum at the end of the instructions that deal with the installation of the dual ECUs. Through numerous emails that I have exc hanged with Robert, I have learned that there the entire system (both ECUs a nd IGN coils) draws 2.4 amps. I have also learned that a single 10A breaker feeds both coils. I would think the 4-diode rectifier with power from the e ngine battery bus and the main battery bus would solve the single-point of f ailure issue with a single power source. The system requires 5 breakers. 2- 5A breakers for the ECUs, 1- 10A breaker for the IGN Coils, and 2- 10A brea kers for the fuel pumps (one each). > > The reason for installing the electrically dependent system is for the per formance gains and the flexibility of using MOGAS. The system draws very li ttle current, and WHEN the alternator fails (and it will at some point), the pilot will be notified (low voltage and low amperage warnings). At this po int the pilot must shed the loads to protect the remaining battery power. T he EFII system will run as low as 6 volts. I feel that with a dual battery s ystem and a way to isolate the batteries from each other during flight, a hi gher level of safety is achieved. The pilot would simply isolate the batter ies and shut off all items that are drawing a load from that battery bus. W hen and if the primary battery=99s voltage gets too low, the pilot sim ply switches to the other battery and lands as soon as POSSIBLE. > > The challenge is to engineer a reliable and redundant 12V system that will allow for safe and reliable operation regardless of individual component, c omplete bus, or even power source failure. > > Any thoughts and tips are much appreciated. I have some experience in 12VD C systems but am by no means an engineer. > > Thanks again for the help! > > Justin > > > On Aug 17, 2014, at 12:02 PM, Robert L. Nuckolls, III wrote: > >> The system requires that both ECUs and both IGN coils are powered all the time . . . >> >> Okay, suppose one of these four items doesn't get power >> while the other three do . . . what happens? >> >> Suppose half of the system ECU and IGN get a momentary >> power interruption, what happens? >> >> Suppose there's complete interruption of power to all >> engine support which is 'fixed' in a few seconds, >> what happens? >> >> The legacy design philosophy we've applied to all >> systems intended for use in unforgiving environments >> is the failure mode effects analysis. FMEA looks at >> every component of the system and asks: >> >> How can this part fail? >> If it does fail, how will I become aware of it? >> If not immediately noticed or annunciated by >> warning system, is it pre-flight detectable? >> If it does fail, how is probable outcome of >> the flight affected? >> If it is necessary for comfortable continuation >> of flight, what are my alternatives? >> >> Here's my personal notions that go to the topic >> of system reliability >> >> Nuckolls' first law of airplane systems design sez: "Things break" >> >> The second: "Systems shall be designed so that when things break, no imme diate hazard is created." >> >> The third: "Failure tolerant design dictates that items needed for >> comfortable termination of flight are backed up with Plan-B alternatives. " >> >> The forth: "Upgrading the quality, reliability, longevity, or >> capability of a part shall be because you're tired of replacing it >> or want some new operating feature, not because it damned near >> got you killed." >> >> Before you march off to craft a never fails power >> source(s) . . . it seems prudent to ASSUME there >> WILL be failures . . . and craft a system that is >> comfortably tolerant of such failures. >> >> Your query to the List cited an imperative for everything >> that supports engine operations to be powered at all >> times . . . if this is strictly true, then are you >> sure that you want to install it on your airplane? >> >> >> >> Bob . . . >> >> >> href="http://www.matronics.com/Navigator?AeroElectric-List">http://www. matronics.com/Navigator?AeroElectric-List >> href="http://forums.matronics.com/">http://forums.matronics.com >> href="http://www.matronics.com/contribution">http://www.matronics.com/c ontribution >> > > --> > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= > ________________________________ Message 2 _____________________________________ Time: 03:38:47 AM PST US From: Justin Jones Subject: Re: AeroElectric-List: Z-19 Function I guess I should have said that 2 single breakers would be powering the coils from 2 different power sources. On Aug 18, 2014, at 2:19 AM, Justin Jones wrote: > Thanks fit the input Jeff. I appreciate it. I like the way redundancy in the system you drew. > > You are correct that a single 10A breaker for both coils is a single point of failure and I don't like it. If a 4-diode rectifier were used with an input from both battery buses, it would solve the issue. Then a single breaker would be powering it them from 2 different power sources. > > > > On Aug 17, 2014, at 20:06, Jeff Luckey wrote: > >> Justin, >> >> ... I have also learned that a single 10A breaker feeds both coils. I would think the 4-diode rectifier with power from the engine battery bus and the main battery bus would solve the single-point of failure issue with a single power source... >> >> Without looking a schematic it is difficult to get a clear picture of what you are describing but a single breaker for both coils? Is that not the definition of a single point of failure? >> >> >> ... I feel that with a dual battery system and a way to isolate the batteries from each other during flight, a higher level of safety is achieved. >> >> Agree. >> >> >> ... The pilot would simply isolate the batteries and shut off all items that are drawing a load from that battery bus. .... >> >> The drawing that I posted yesterday does the isolation you are talking about but it does so automatically without any interruption of current flow and requires no pilot interaction. >> >> >> The challenge is to engineer a reliable and redundant 12V system that will allow for safe and reliable operation regardless of individual component, complete bus, or even power source failure. >> >> This wheel has been invented many times over. Between Bob N's Z drawing(s) and the one I posted, you should be able accomplish your goals. >> >> >> -Jeff >> >> >> On Sunday, August 17, 2014 8:37 PM, Justin Jones wrote: >> >> >> Here is the link to the downloadable instruction manual. http://flyefii.com/customer_projects/EFII_Ignition_Instruction_sheet_rev9- 13.pdf >> >> There is a Dual ECU addendum at the end of the instructions that deal with the installation of the dual ECUs. Through numerous emails that I have exchanged with Robert, I have learned that there the entire system (both ECUs and IGN coils) draws 2.4 amps. I have also learned that a single 10A breaker feeds both coils. I would think the 4-diode rectifier with power from the engine battery bus and the main battery bus would solve the single-point of failure issue with a single power source. The system requires 5 breakers. 2- 5A breakers for the ECUs, 1- 10A breaker for the IGN Coils, and 2- 10A breakers for the fuel pumps (one each). >> >> The reason for installing the electrically dependent system is for the performance gains and the flexibility of using MOGAS. The system draws very little current, and WHEN the alternator fails (and it will at some point), the pilot will be notified (low voltage and low amperage warnings). At this point the pilot must shed the loads to protect the remaining battery power. The EFII system will run as low as 6 volts. I feel that with a dual battery system and a way to isolate the batteries from each other during flight, a higher level of safety is achieved. The pilot would simply isolate the batteries and shut off all items that are drawing a load from that battery bus. When and if the primary battery=92s voltage gets too low, the pilot simply switches to the other battery and lands as soon as POSSIBLE. >> >> The challenge is to engineer a reliable and redundant 12V system that will allow for safe and reliable operation regardless of individual component, complete bus, or even power source failure. >> >> Any thoughts and tips are much appreciated. I have some experience in 12VDC systems but am by no means an engineer. >> >> Thanks again for the help! >> >> Justin >> >> >> On Aug 17, 2014, at 12:02 PM, Robert L. Nuckolls, III wrote: >> >>> The system requires that both ECUs and both IGN coils are powered all the time . . . >>> >>> Okay, suppose one of these four items doesn't get power >>> while the other three do . . . what happens? >>> >>> Suppose half of the system ECU and IGN get a momentary >>> power interruption, what happens? >>> >>> Suppose there's complete interruption of power to all >>> engine support which is 'fixed' in a few seconds, >>> what happens? >>> >>> The legacy design philosophy we've applied to all >>> systems intended for use in unforgiving environments >>> is the failure mode effects analysis. FMEA looks at >>> every component of the system and asks: >>> >>> How can this part fail? >>> If it does fail, how will I become aware of it? >>> If not immediately noticed or annunciated by >>> warning system, is it pre-flight detectable? >>> If it does fail, how is probable outcome of >>> the flight affected? >>> If it is necessary for comfortable continuation >>> of flight, what are my alternatives? >>> >>> Here's my personal notions that go to the topic >>> of system reliability >>> >>> Nuckolls' first law of airplane systems design sez: "Things break" >>> >>> The second: "Systems shall be designed so that when things break, no immediate hazard is created." >>> >>> The third: "Failure tolerant design dictates that items needed for >>> comfortable termination of flight are backed up with Plan-B alternatives." >>> >>> The forth: "Upgrading the quality, reliability, longevity, or >>> capability of a part shall be because you're tired of replacing it >>> or want some new operating feature, not because it damned near >>> got you killed." >>> >>> Before you march off to craft a never fails power >>> source(s) . . . it seems prudent to ASSUME there >>> WILL be failures . . . and craft a system that is >>> comfortably tolerant of such failures. >>> >>> Your query to the List cited an imperative for everything >>> that supports engine operations to be powered at all >>> times . . . if this is strictly true, then are you >>> sure that you want to install it on your airplane? >>> >>> >>> >>> Bob . . . >>> >>> >>> href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.m atronics.com/Navigator?AeroElectric-List >>> href="http://forums.matronics.com/">http://forums.matronics.com >>> href="http://www.matronics.com/contribution">http://www.matronics.com/co ntribution >>> >> >> --> >> >> >> ======================== >> courier new,courier">http://www.matronics.com/Navigator?AeroElectric-List >> ======================== >> cs.com >> ======================== >> matronics.com/contribution >> ======================== >> > > > ________________________________ Message 3 _____________________________________ Time: 07:00:26 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-19 Function At 12:53 AM 8/18/2014, you wrote: >http://www.flyefii.com/customer_projects/EFII_Installation_Manual_rev9-13.pdf Hmmmm . . . These systems probably perform as advertised . . . but the supplier has not served their customer well in terms of system integration data. In particular, their treatment of electrical systems architecture and failure modes is sketchy to non-existent. The word 'fail' appears three times . . . not in the context of a system integrator's work instruction or pilot's operating manual . . . but of a marketing brochure. I went back into the series of Justin's postings . . . the first one showed up in February of this year. It seems that by the time he first came to the List, drawings were made, parts bought, holes drilled and a lot of decisions already under the bridge were being 'fine tuned'. I am not pleased to note that this project is probably way too complex for reasons not well defined. If the supplier of this system has offered nothing more than the documents cited, then he is . . . well. Suffice it to say that if I walked into some airframe OEM attempting to sell this hardware on no better data . . . I wouldn't get past the purchasing agents. Just because our airplanes are relatively unregulated and 'experimental' does not relieve any supplier of a duty to reduce costs and risk. This is especially true when the product is being offered to a non-professional marketplace. I have often opined here on the List that every electrical system . . . ESPECIALLY one with the potential for complexity as this one . . . should start with the bus-by-bus load analysis. This exercise starts the thinking processes that guide hardware sizing and architecture decisions that go to the elegant (read frugal) design. I've been struggling with a task for a client to refine requirements documents on a system that has already been built. It DOES function as advertised . . . but its schematic has the appearance of a bucket full of parts stirred vigorously with a paint mixer until desired functionality was achieved. The problem I'm wrestling with is whether or not I want to continue to pursue the task for the client. Once the documentation is completed, do I want to sign the author's signature line? Doing so would add my own credential to an activity which (in my never humble opinion) does not serve the end-user well for cost of ownership and mitigation of risk. Justin's project presents a similar conundrum. I'm recalling a conversation with a builder about 20 years ago who said, "I shielded all the wires and installed filters here, there, and a few over there . . . what else do I need?" I asked, "Gee, do you have a noise problem?" "Oh no . . . I haven't flown the airplane yet." Justin has not been well served by his suppliers and is struggling with issues that should have been put to bed before he made his decision to purchase the system. It's not clear to what advice we can offer that would markedly refine a system that's already built. Justin, One thing I gleaned from the data package: With the exception of fuel injectors, the two systems are entirely redundant. Should one of the systems become unusable for any reason, including loss of power, then the other system can be pressed into service with no significant loss of engine performance. The manufacturer's citation of breaker sizes tells us NOTHING about this system's energy needs. You would do well to approach them with questions that go to ENERGY that moves through each breaker and under what conditions. I apologize for pushing this off on you . . . but these guys need to understand the problems THEIR customers are wrestling with. I could write and ask for the same data . . . but I would not be surprised if they don't really know the answers. This study needs to start with a customer . . . and you're the only one I know. If inquiring minds seek to be helpful, then it's something we need to know. If their answers seem less than confident, suggest that they contact me . . . or better yet, join the AeroElectric-List. There is no better opportunity for teaching responsible consumerism than to carry out our conversations with the supplier in open forum. Bob . . . ________________________________ Message 4 _____________________________________ Time: 10:11:22 AM PST US From: Ken Ryan Subject: Re: AeroElectric-List: Z-19 Function Justin, Have you considered using Robert's Bus Manager? It allows for two batteries, isolated for charging. Either or both batteries can be used for starting, and there is great redundancy for power to the essential bus. Also, it will monitor fuel pressure and automatically switch to the auxiliary pump if pressure is lost. Ken On Sun, Aug 17, 2014 at 7:25 PM, Justin Jones wrote: > Here is the link to the downloadable instruction manual. > http://flyefii.com/customer_projects/EFII_Ignition_Instruction_sheet_rev9 -13.pdf > > There is a Dual ECU addendum at the end of the instructions that deal wit h > the installation of the dual ECUs. Through numerous emails that I have > exchanged with Robert, I have learned that there the entire system (both > ECUs and IGN coils) draws 2.4 amps. I have also learned that a single 10 A > breaker feeds both coils. I would think the 4-diode rectifier with power > from the engine battery bus and the main battery bus would solve the > single-point of failure issue with a single power source. The system > requires 5 breakers. 2- 5A breakers for the ECUs, 1- 10A breaker for the > IGN Coils, and 2- 10A breakers for the fuel pumps (one each). > > The reason for installing the electrically dependent system is for the > performance gains and the flexibility of using MOGAS. The system draws > very little current, and WHEN the alternator fails (and it will at some > point), the pilot will be notified (low voltage and low amperage warnings ). > At this point the pilot must shed the loads to protect the remaining > battery power. The EFII system will run as low as 6 volts. I feel that > with a dual battery system and a way to isolate the batteries from each > other during flight, a higher level of safety is achieved. The pilot wou ld > simply isolate the batteries and shut off all items that are drawing a lo ad > from that battery bus. When and if the primary battery=99s voltage gets too > low, the pilot simply switches to the other battery and lands as soon as > POSSIBLE. > > The challenge is to engineer a reliable and redundant 12V system that wil l > allow for safe and reliable operation regardless of individual component, > complete bus, or even power source failure. > > Any thoughts and tips are much appreciated. I have some experience in > 12VDC systems but am by no means an engineer. > > Thanks again for the help! > > Justin > > > On Aug 17, 2014, at 12:02 PM, Robert L. Nuckolls, III < > nuckolls.bob@aeroelectric.com> wrote: > > The system requires that both ECUs and both IGN coils are powered all th e > time . . . > > Okay, suppose one of these four items doesn't get power > while the other three do . . . what happens? > > Suppose half of the system ECU and IGN get a momentary > power interruption, what happens? > > Suppose there's complete interruption of power to all > engine support which is 'fixed' in a few seconds, > what happens? > > The legacy design philosophy we've applied to all > systems intended for use in unforgiving environments > is the failure mode effects analysis. FMEA looks at > every component of the system and asks: > > > *How can this part fail? * > *If it does fail, how will I become aware of it? **If not immediately > noticed or annunciated by * > *warning system, is it pre-flight detectable? **If it does fail, how is > probable outcome of * > *the flight affected? **If it is necessary for comfortable continuation * > > *of flight, what are my alternatives?* Here's my personal notions that > go to the topic > of system reliability > > *Nuckolls' first law of airplane systems design sez:* "Things break" * The > second:* "Systems shall be designed so that when things break, no > immediate hazard is created." *The third:* "Failure tolerant design > dictates that items needed for comfortable termination of flight are > backed up with Plan-B alternatives." *The forth:* "Upgrading the > quality, reliability, longevity, or capability of a part shall be because > you're tired of replacing it or want some new operating feature, not > because it damned near got you killed." > > Before you march off to craft a never fails power > source(s) . . . it seems prudent to ASSUME there > WILL be failures . . . and craft a system that is > comfortably tolerant of such failures. > > Your query to the List cited an imperative for everything > that supports engine operations to be powered at all > times . . . if this is strictly true, then are you > sure that you want to install it on your airplane? > > > Bob . . . > > * > > href="http://www.matronics.com/Navigator?AeroElectric-List ">http://www.matronics.com/Naviga tor?AeroElectric-List > href="http://forums.matronics.com/ ">http ://forums.matronics.com > href="http://www.matronics.com/contribution ">http://www.matronics.com/contribution > > * > > > * > =========== www.matronics.com/Navigator?AeroElectric-List> =========== =========== om/contribution> =========== > > * > > ________________________________ Message 5 _____________________________________ Time: 10:36:45 AM PST US From: Justin Jones Subject: Re: AeroElectric-List: Z-19 Function Bob, I appreciate your help and opinion with this matter. I will approach Robert about this and find out the specifics of the electrical demands of his system. I have heard great things about his customer service and the folks using his system in their running aircraft have nothing but great things to say about it and him. He is a very knowledgable A&P and has deep knowledge of his system. Thank you again. Justin On Aug 18, 2014, at 5:59 AM, Robert L. Nuckolls, III wrote: > At 12:53 AM 8/18/2014, you wrote: > >> http://www.flyefii.com/customer_projects/EFII_Installation_Manual_rev9-13. pdf > > Hmmmm . . . These systems probably perform as advertised . . . > but the supplier has not served their customer well in > terms of system integration data. In particular, their treatment > of electrical systems architecture and failure modes is > sketchy to non-existent. The word 'fail' appears three > times . . . not in the context of a system integrator's > work instruction or pilot's operating manual . . . but of > a marketing brochure. > > I went back into the series of Justin's postings . . . the first > one showed up in February of this year. It seems that by the > time he first came to the List, drawings were made, parts bought, > holes drilled and a lot of decisions already under the bridge > were being 'fine tuned'. > > I am not pleased to note that this project is probably way > too complex for reasons not well defined. If the supplier > of this system has offered nothing more than the documents > cited, then he is . . . well. Suffice it to say that > if I walked into some airframe OEM attempting to sell this > hardware on no better data . . . I wouldn't get past the > purchasing agents. > > Just because our airplanes are relatively unregulated and > 'experimental' does not relieve any supplier of a duty > to reduce costs and risk. This is especially true when the product is > being offered to a non-professional marketplace. > > I have often opined here on the List that every electrical > system . . . ESPECIALLY one with the potential for complexity > as this one . . . should start with the bus-by-bus load analysis. > This exercise starts the thinking processes that guide hardware > sizing and architecture decisions that go to the elegant (read > frugal) design. > > I've been struggling with a task for a client to refine > requirements documents on a system that has already been > built. It DOES function as advertised . . . but its schematic > has the appearance of a bucket full of parts stirred > vigorously with a paint mixer until desired functionality was > achieved. > > The problem I'm wrestling with is whether or not I want > to continue to pursue the task for the client. Once the > documentation is completed, do I want to sign the > author's signature line? Doing so would add my own > credential to an activity which (in my never humble > opinion) does not serve the end-user well for cost of > ownership and mitigation of risk. > > Justin's project presents a similar conundrum. I'm recalling > a conversation with a builder about 20 years ago who said, > "I shielded all the wires and installed filters here, there, > and a few over there . . . what else do I need?" > > I asked, "Gee, do you have a noise problem?" > > "Oh no . . . I haven't flown the airplane yet." > > Justin has not been well served by his suppliers > and is struggling with issues that should have > been put to bed before he made his decision to > purchase the system. > > It's not clear to what advice we can offer that > would markedly refine a system that's already > built. > > Justin, > > One thing I gleaned from the data package: > With the exception of fuel injectors, the two systems > are entirely redundant. Should one of the systems > become unusable for any reason, including loss of > power, then the other system can be pressed into > service with no significant loss of engine performance. > > The manufacturer's citation of breaker sizes tells > us NOTHING about this system's energy needs. You > would do well to approach them with questions > that go to ENERGY that moves through each breaker > and under what conditions. > > I apologize for pushing this off on you . . . but > these guys need to understand the problems THEIR > customers are wrestling with. I could write and ask > for the same data . . . but I would not be surprised > if they don't really know the answers. This study > needs to start with a customer . . . and you're > the only one I know. > > If inquiring minds seek to be helpful, then > it's something we need to know. If their answers > seem less than confident, suggest that they contact > me . . . or better yet, join the AeroElectric-List. > There is no better opportunity for teaching > responsible consumerism than to carry out our > conversations with the supplier in open forum. > > Bob . . . > > > > ________________________________ Message 6 _____________________________________ Time: 10:42:11 AM PST US From: Justin Jones Subject: Re: AeroElectric-List: Z-19 Function Ken, I have considered using it. I am left wondering if his system has the same functions of Bob=92s Z-19 diagram, and his other diagrams for electrically dependent engines. If it does (and it seems to) it seems that it would be an added cost for no good reason. Here is the link to the Bus Manager Installation instructions. http://flyefii.com/bus_manager/Bus_Manager_Installation_Instructions.pdf Maybe Bob can weigh in on the Bus Manager? Thanks Justin On Aug 18, 2014, at 9:09 AM, Ken Ryan wrote: > Justin, > > Have you considered using Robert's Bus Manager? It allows for two batteries, isolated for charging. Either or both batteries can be used for starting, and there is great redundancy for power to the essential bus. Also, it will monitor fuel pressure and automatically switch to the auxiliary pump if pressure is lost. > > Ken > > > On Sun, Aug 17, 2014 at 7:25 PM, Justin Jones wrote: > Here is the link to the downloadable instruction manual. http://flyefii.com/customer_projects/EFII_Ignition_Instruction_sheet_rev9- 13.pdf > > There is a Dual ECU addendum at the end of the instructions that deal with the installation of the dual ECUs. Through numerous emails that I have exchanged with Robert, I have learned that there the entire system (both ECUs and IGN coils) draws 2.4 amps. I have also learned that a single 10A breaker feeds both coils. I would think the 4-diode rectifier with power from the engine battery bus and the main battery bus would solve the single-point of failure issue with a single power source. The system requires 5 breakers. 2- 5A breakers for the ECUs, 1- 10A breaker for the IGN Coils, and 2- 10A breakers for the fuel pumps (one each). > > The reason for installing the electrically dependent system is for the performance gains and the flexibility of using MOGAS. The system draws very little current, and WHEN the alternator fails (and it will at some point), the pilot will be notified (low voltage and low amperage warnings). At this point the pilot must shed the loads to protect the remaining battery power. The EFII system will run as low as 6 volts. I feel that with a dual battery system and a way to isolate the batteries from each other during flight, a higher level of safety is achieved. The pilot would simply isolate the batteries and shut off all items that are drawing a load from that battery bus. When and if the primary battery=92s voltage gets too low, the pilot simply switches to the other battery and lands as soon as POSSIBLE. > > The challenge is to engineer a reliable and redundant 12V system that will allow for safe and reliable operation regardless of individual component, complete bus, or even power source failure. > > Any thoughts and tips are much appreciated. I have some experience in 12VDC systems but am by no means an engineer. > > Thanks again for the help! > > Justin > > > On Aug 17, 2014, at 12:02 PM, Robert L. Nuckolls, III wrote: > >> The system requires that both ECUs and both IGN coils are powered all the time . . . >> >> Okay, suppose one of these four items doesn't get power >> while the other three do . . . what happens? >> >> Suppose half of the system ECU and IGN get a momentary >> power interruption, what happens? >> >> Suppose there's complete interruption of power to all >> engine support which is 'fixed' in a few seconds, >> what happens? >> >> The legacy design philosophy we've applied to all >> systems intended for use in unforgiving environments >> is the failure mode effects analysis. FMEA looks at >> every component of the system and asks: >> >> How can this part fail? >> If it does fail, how will I become aware of it? >> If not immediately noticed or annunciated by >> warning system, is it pre-flight detectable? >> If it does fail, how is probable outcome of >> the flight affected? >> If it is necessary for comfortable continuation >> of flight, what are my alternatives? >> >> Here's my personal notions that go to the topic >> of system reliability >> >> Nuckolls' first law of airplane systems design sez: "Things break" >> >> The second: "Systems shall be designed so that when things break, no immediate hazard is created." >> >> The third: "Failure tolerant design dictates that items needed for >> comfortable termination of flight are backed up with Plan-B alternatives." >> >> The forth: "Upgrading the quality, reliability, longevity, or >> capability of a part shall be because you're tired of replacing it >> or want some new operating feature, not because it damned near >> got you killed." >> >> Before you march off to craft a never fails power >> source(s) . . . it seems prudent to ASSUME there >> WILL be failures . . . and craft a system that is >> comfortably tolerant of such failures. >> >> Your query to the List cited an imperative for everything >> that supports engine operations to be powered at all >> times . . . if this is strictly true, then are you >> sure that you want to install it on your airplane? >> >> >> >> Bob . . . >> >> >> >> href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.m atronics.com/Navigator?AeroElectric-List >> href="http://forums.matronics.com/">http://forums.matronics.com >> href="http://www.matronics.com/contribution">http://www.matronics.com/co ntribution >> > > > > ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List > tp://forums.matronics.com > _blank">http://www.matronics.com/contribution > > > > > ________________________________ Message 7 _____________________________________ Time: 11:50:28 AM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: Z-19 Function Justin,=0A=0ASomeone mentioned the Bus Manager product. I am not privy to i ts design but that same functionality is provided in the system design that I posted, except for the fuel pump management.=0A=0A-Jeff=0A=0A=0A=0AOn Mo nday, August 18, 2014 10:56 AM, Justin Jones w rote:=0A =0A=0A=0ABob,=0A=0AI appreciate your help and opinion with this ma tter. -I will approach Robert about this and find out the specifics of th e electrical demands of his system. -I have heard great things about his customer service and the folks using his system in their running aircraft h ave nothing but great things to say about it and him. -He is a very knowl edgable A&P and has deep knowledge of his system.=0A=0AThank you again.=0A =0AJustin-=0A=0A=0A=0AOn Aug 18, 2014, at 5:59 AM, Robert L. Nuckolls, II I wrote:=0A=0AAt 12:53 AM 8/18/2014, you wr ote:=0A>=0A>=0A>http://www.flyefii.com/customer_projects/EFII_Installation_ Manual_rev9-13.pdf =0A>-- Hmmmm . . . These systems probably perform as advertised . .=0A.=0A>-- but the supplier has not served their custome r well in=0A>-- terms of system integration data. In particular, their =0Atreatment=0A>-- of electrical systems architecture and failure modes is=0A>-- sketchy to non-existent. The word 'fail' appears three=0A>- - times . . . not in the context of a system integrator's=0A>-- work instruction or pilot's operating manual . . . but=0Aof=0A>-- a marketin g brochure. =0A>=0A>-- I went back into the series of Justin's postings . . . the=0Afirst=0A>-- one showed up in February of this year. It see ms that by=0Athe=0A>-- time he first came to the List, drawings were ma de, parts=0Abought,=0A>-- holes drilled and a lot of decisions already under the=0Abridge=0A>-- were being 'fine tuned'.=0A>=0A>-- I am no t pleased to note that this project is probably=0Away=0A>-- too complex for reasons not well defined. If the=0Asupplier=0A>-- of this system h as offered nothing more than the=0Adocuments=0A>-- cited, then he is . . . well. Suffice it to say that=0A>-- if I walked into some airframe O EM attempting to sell=0Athis=0A>-- hardware on no better data . . . I w ouldn't get past=0Athe=0A>-- purchasing agents.=0A>=0A>-- Just beca use our airplanes are relatively unregulated=0Aand=0A>-- 'experimental' does not relieve any supplier of a duty=0A>-- to reduce costs and risk . This is especially true when the=0Aproduct is=0A>-- being offered to a non-professional marketplace.=0A>=0A>-- I have often opined here on t he List that every=0Aelectrical=0A>-- system . . . ESPECIALLY one with the potential for=0Acomplexity=0A>-- as this one . . . should start wit h the bus-by-bus load=0Aanalysis.=0A>-- This exercise starts the thinki ng processes that guide=0Ahardware=0A>-- sizing and architecture decisi ons that go to the elegant=0A(read=0A>-- frugal) design.=0A>=0A>-- I've been struggling with a task for a client to refine=0A>-- requireme nts documents on a system that has already=0Abeen=0A>-- built. It DOES function as advertised . . . but its=0Aschematic=0A>-- has the appearan ce of a bucket full of parts stirred=0A>-- vigorously with a paint mixe r until desired functionality=0Awas=0A>-- achieved.=0A>=0A>-- The p roblem I'm wrestling with is whether or not I want=0A>-- to continue to pursue the task for the client. Once the=0A>-- documentation is comple ted, do I want to sign the=0A>-- author's signature line? Doing so woul d add my own=0A>-- credential to an activity which (in my never humble =0A>-- opinion) does not serve the end-user well for cost of=0A>-- ownership and mitigation of risk.=0A>=0A>-- Justin's project presents a similar conundrum. I'm=0Arecalling=0A>-- a conversation with a builder about 20 years ago who=0Asaid,=0A>-- "I shielded all the wires and ins talled filters here,=0Athere,=0A>-- and a few over there . . . what els e do I=0Aneed?"=0A>=0A>-- I asked, "Gee, do you have a noise=0Aproblem? "=0A>=0A>-- "Oh no . . . I haven't flown the airplane=0Ayet."=0A>=0A> -- Justin has not been well served by his suppliers=0A>-- and is st ruggling with issues that should have=0A>-- been put to bed before he m ade his decision to=0A>-- purchase the system.=0A>=0A>-- It's not c lear to what advice we can offer that=0A>-- would markedly refine a sys tem that's already=0A>-- built.=0A>=0A>-- Justin, =0A>=0A>-- On e thing I gleaned from the data package: =0A>-- With the exception of f uel injectors, the two systems=0A>-- are entirely redundant. Should one of the systems=0A>-- become unusable for any reason, including loss of =0A>-- power, then the other system can be pressed into=0A>-- servi ce with no significant loss of engine=0Aperformance.=0A>=0A>-- The manu facturer's citation of breaker sizes tells=0A>-- us NOTHING about this system's energy needs. You=0A>-- would do well to approach them with qu estions=0A>-- that go to ENERGY that moves through each breaker=0A>- - and under what conditions.=0A>=0A>-- I apologize for pushing this o ff on you . . . but=0A>-- these guys need to understand the problems TH EIR=0A>-- customers are wrestling with. I could write and ask=0A>-- for the same data . . . but I would not be surprised=0A>-- if they don 't really know the answers. This study=0A>-- needs to start with a cust omer . . . and you're=0A>-- the only one I know.=0A>=0A>-- If inqui ring minds seek to be helpful, then=0A>-- it's something we need to kno w. If their answers=0A>-- seem less than confident, suggest that they c ontact=0A>-- me . . . or better yet, join the AeroElectric-List.=0A>- - There is no better opportunity for teaching =0A>-- responsible cons umerism than to carry out our=0A>-- conversations with the supplier in =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D ________________________________ Message 8 _____________________________________ Time: 03:26:03 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-19 Function At 01:49 PM 8/18/2014, you wrote: >Justin, > >Someone mentioned the Bus Manager product. I am not privy to its >design but that same functionality is provided in the system design >that I posted, except for the fuel pump management. > >-Jeff This might well be marching off in the wrong direction. Given what I understand about the engine accessories now, it's not clear that this installation's optimum configuration would not be well served with Z-13/8 or at worst, Z-12 with a 20A s/b alternator and one battery. Z-19 was tailored to engines that could not conveniently drive two alternators. Bob . . . ________________________________ Message 9 _____________________________________ Time: 07:44:14 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Real life lessons in wire ratings . . . Last weekend, Dr. Dee and I spent Friday/Saturday supporting our son's shaved ice and cotton candy business during "Old Settlers Days" in Mulvane, KS. Temperature in upper 90s. Shaved ice trailer with lights, rooftop a/c, freezer and shaved ice machine running on ac mains through 100', 12AWG extension cord not unlike that pictured below. Total current draw on the order of 13 amps. Emacs! Approximately 70' of cord was spooled out leaving about 30' still coiled on the reel. After 3 or 4 hours operation, a vendor on the row behind us asked if that 'smoke and bad smell' was something to be concerned about. I swapped out the smoking cord for a spare. I un-spooled the rest of the cord and discovered that when not allowed the benefits of cooling air, the wrapped up coils got pretty hot. The cord that was spooled out was warmer than ambient but not markedly so. Voltage at plug end under load was 124 volts . . . inside trailer it was 117 volts for a round trip drop of about 7 volts. Nonetheless, insulation on the poorly cooled wires inside the yellow jacket fused together. In some places the yellow jacket was breached and/or fused to adjacent turns. This cord reel is designed to encourage rolling out only that cordage which is needed . . . but if you're going to load it to near max ratings, then it's a good idea to un-spool the entire length. A profound demonstration of how temp rise on a wire is exacerbated by constriction of free air cooling. I cut off the damaged 30', installed a new plug and left the full in-service length of cord laid out on the ground for the rest of the event. Voltage drop went down to just over 5 volts on the shortened cord. Bob . . . ________________________________ Message 10 ____________________________________ Time: 07:52:47 PM PST US Subject: AeroElectric-List: Dynon D-180 & flickering LEDs From: "user9253" I have been corresponding with a RV-12 owner in TX. His Dynon D-180 has a problem with LEDs that flicker when they should be on steady. The D-180 supplies negative PWM voltage to LEDs which are external to the D-180. Download the D-180 Installation Manual http://www.dynonavionics.com/downloads/Install_Guides/FlightDEK-D180_Installation_Guide_Rev_H.pdf and read about "External EMS Warning Light" on page 4-10. The aircraft owner did some experiments. Here are the results: With the engine off and the D-180 powered by the aircraft battery, the LEDs are on steady. With the engine running, the LEDs flicker. With the engine still running, if the avionics switch is shut off, the D-180 reverts to its internal backup battery and the LEDs illuminate steadily. Engine still running and the avionics switch is turned back on, the LEDs flicker again. This experiment was repeated and the results are consistent. From these experiments I conclude that the D-180 puts out a steady PWM voltage when operating on battery power (whether aircraft battery or internal backup battery). And when operating off the alternator, the D-180 puts out an intermittent PWM voltage which causes LED flicker. With the engine running, the D-180 indicates a system voltage of 13.7 which is normal for RV-12s. All E-LSA RV-12s have a 22,000 microfarad capacitor connected to the output of the Rotax rectifier/regualtor. If that capacitor is bad, could that cause the D-180 to output an unsteady PWM voltage to the the LEDs? Or should the D-180 be able to function even if the aircraft electrical power is dirty and not pure DC? Thanks, Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=428713#428713 ------------------------------------------------------------------------------------- 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.