---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 10/11/13: 38 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:00 AM - Re: B-787 Li-Ion battery story continues (Jan de Jong) 2. 04:36 AM - Re: B-787 Li-Ion battery story continues (James Kilford) 3. 05:11 AM - Re: iPad charger? (Bill Watson) 4. 05:18 AM - Congratulations, Bob! (Henador Titzoff) 5. 05:31 AM - Re: iPad charger? (Henador Titzoff) 6. 05:41 AM - Re: B-787 Li-Ion battery story continues (Peter Pengilly) 7. 07:06 AM - Re: iPad charger? (earl_schroeder@juno.com) 8. 07:07 AM - Re: Congratulations, Bob! (Robert L. Nuckolls, III) 9. 07:18 AM - Re: iPad charger? () 10. 07:19 AM - Re: iPad charger? (Eric M. Jones) 11. 07:23 AM - Re: Congratulations, Bob! () 12. 07:26 AM - Re: iPad charger? (Robert L. Nuckolls, III) 13. 07:30 AM - Re: Re: iPad charger? () 14. 07:37 AM - Re: Congratulations, Bob! (Peter Pengilly) 15. 08:00 AM - Re: iPad charger? (earl_schroeder@juno.com) 16. 08:36 AM - Re: Charge battery thru Ground Power Jack (jonlaury) 17. 09:34 AM - Re: Re: Charge battery thru Ground Power Jack (Robert L. Nuckolls, III) 18. 09:37 AM - Cover of Revision 13 (Robert L. Nuckolls, III) 19. 09:50 AM - Re: B-787 Li-Ion battery story continues (BobsV35B@aol.com) 20. 09:53 AM - Re: Cover of Revision 13 (James Kilford) 21. 09:55 AM - Re: iPad charger? (Eric Page) 22. 09:58 AM - Re: B-787 Li-Ion battery story continues (Eric Page) 23. 10:13 AM - Words as parts (Robert L. Nuckolls, III) 24. 10:18 AM - Re: Charge battery thru Ground Power Jack (user9253) 25. 10:26 AM - Re: Cover of Revision 13 (Robert L. Nuckolls, III) 26. 10:32 AM - Re: Re: Charge battery thru Ground Power Jack (Robert L. Nuckolls, III) 27. 10:50 AM - Re: Re: iPad charger? (Sacha) 28. 11:19 AM - Relay for Critical Power Feed (Thomas E Blejwas) 29. 11:47 AM - Re: Cover of Revision 13 (Gerry van Dyk) 30. 02:48 PM - Re: Re: iPad charger? (Eric Page) 31. 04:30 PM - Re: Relay for Critical Power Feed (Eric Page) 32. 04:59 PM - Re: Re: iPad charger? (Eric Page) 33. 06:14 PM - Re: Cover of Revision 13 (Robert L. Nuckolls, III) 34. 08:04 PM - Re: Cover of Revision 13 (Sacha) 35. 08:12 PM - Re: Re: iPad charger? (Sacha) 36. 08:49 PM - Re: Cover of Revision 13 (Bill) 37. 10:01 PM - Re: Re: iPad charger? (Verso Electronics) 38. 11:36 PM - EXP 2 Bus workaround (Fred Klein) ________________________________ Message 1 _____________________________________ Time: 03:00:05 AM PST US From: Jan de Jong Subject: Re: AeroElectric-List: B-787 Li-Ion battery story continues Hi Bob, I agree. Over-discharging and then recharging at full speed is a reported safety issue. I wondered about the mention of discharge by itself ("starting an APU") as a safety issue. Maybe the increased internal resistance (50 to 100% increase at 15% SOC I saw somewhere) makes it so. On the other hand, the exothermal reaction starts more slowly and is less violent in a discharged cell. Bottom line - I should have kept my peace. Jan de Jong On 10/10/2013 3:29 PM, Robert L. Nuckolls, III wrote: > > > At 06:46 AM 10/10/2013, you wrote: >> >> >> I am puzzled by the article of the recent addition, that states that >> a li-ion battery is especially prone to destructive thermal runaway >> when discharged. >> I do not believe this is true, on the contrary. > > Can you elaborate? I've read from several sources that > the Li-Ion technologies are at greatest risk for unhappy > thermal events when they're discharged and then RECHARGED > without regard to their special needs. > > The cell's tendency to dissipate heat internally is highest > when at a low state of charge (a state if higher internal > resistance?) is combined with legacy recharge philosophies > for allowing say a 60A alternator to run essentially full-bore to > bring the battery back up to full charge. > > Hence, the "special chargers" that plug into dedicated > connectors on some products for the purpose of achieving > a fully charged battery after deep discharge. > > I think this is the condition being described in the > article. It's also a condition that seems to be ignored > the literature by some suppliers of Li-Ion products. > It's a fundamental question to be explored about the > suitability of an Li-Ion product as a drop-in, plug-n-play > replacement for a lead-acid battery. > > Boeing seems to have given due diligence to this > phenomenon by stating that a battery allowed to discharge > below some value is considered 'scrap' . . . hence the > multiple replacements of batteries in the field . . . > batteries that were retired much too early. I wonder if > these were 'recycled' in any way . . . perhaps returned > to a battery lab where they were carefully recharged and > perhaps returned to service? > > I think I've read elsewhere that some suppliers of > commercial off the shelf Li-Ion batteries suggest that > a battery not be discharged below 30% of full capacity. > If this is good advice, then one would want to (1) either > select new batteries with 30% more headroom for capacity > in the endurance mode and then monitored for load-shedding > at 30% and/or (2) take extra care in recharging the > battery should you take it down too far . . . don't let > your alternator do it. > > Our friends at Cessna are still sifting the simple-ideas > that drive this technology. I'll be working in the same > building with these folks which may add to my own > understanding along with some simple-ideas that can be > shared. Got to be careful here. Contractors > and employees alike sign non-disclosure agreements. But > no doubt, the simple ideas that drive the physics of > battery performance are not going to be any kind of > 'secret' . . . these are the ingredients that drive > risks and successes in the marketplace and will have > to be well understood by everybody. There is still much to > learn my friends. I'll remain cautious with any advice I > have for dropping this technology into an OBAM aircraft. > Setting airplanes on fire is really bad for business. > > > Bob . . . > ________________________________ Message 2 _____________________________________ Time: 04:36:32 AM PST US Subject: Re: AeroElectric-List: B-787 Li-Ion battery story continues From: James Kilford Some interesting stuff in there Bob. Two things in particular stood out: 1) Are customers going to have the appetite for the increase in useful load when compared with the risk associated with the new battery technology, when such benign alternatives exist? 2) What is the wisdom of making things so different for ground crew on one Boeing aeroplane? It seems to be tempting fate by making ground operations different. In my line of work the non-functional requirements are often the ones that bite you, and perhaps this is a similar case. James On 10 October 2013 04:03, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > > I've published a compendium of articles on the B787 > battery story at: > > http://tinyurl.com/ag2e9xk > > but in particular, there's a recent addition that > adds a lot of useful information > > http://tinyurl.com/lyc5845 > > > Bob . . . > > ________________________________ Message 3 _____________________________________ Time: 05:11:00 AM PST US From: Bill Watson Subject: Re: AeroElectric-List: iPad charger? Add me to the list - I already have the panel spot and fuse slot identified. Is there an 'easy' way to determine externally whether a given cheapo or high price cig plug usb charger is the switcher/linear regulator type or the type that has some chance of working for awhile? 'Easy' being defined as with a multi-meter or perhaps even a quick peek inside. I've been thru a number myself. I have one that seems to work on my other non-iPad devices but I've been saving it for an emergency iPad charge. In the end, I was so ashamed of having cigarette plug in my '10 that I hid it behind a back seat cushion. Given the variety of devices needing a USB charge, I can't wait to put something up front. I figure by the time I get it, the USB standard will change but that's life. Bill On 10/10/2013 8:48 PM, Eric Page wrote: > > Rumen: No worries. I think I've seen three Erics on the List! I haven't seen the charger you've got, but I'm sure it's a switcher. They all are. Getting enough current at 5V to rapid-charge an iPad through a linear regulator fed with 14V would make an 18-watt heater! > > Marvin: Panel mounted and hard wired is exactly my plan. Nice, neat installation and zero hassle during use. > > Michael and Earl: Thanks for your interest; I'll add you to my contact list. > > Cheers, > > Eric > > do not archive > > ________________________________ Message 4 _____________________________________ Time: 05:18:33 AM PST US From: Henador Titzoff Subject: AeroElectric-List: Congratulations, Bob! Bob,=0A=0AMany people have chimed in about your contract job with Cessna. I want to congratulate you, too.- I think you are a great asset in the OBA M world and will help Cesspool become Cessna again.=0A=0ASuch jobs require a lot of time. I can't help but think that your AE activities will slow dow n, since there's only so many femtoseconds in a day. It's okay. Do a great job at Cessna and- whatever time you have left is good enough for us. Hop efully your home lab activities will be supplanted by Cessna lab activities , which means you will be helping both entities.=0A=0AIf contracting pays o ff big time, perhaps you will find it in your heart to send us all $100 so we can get through the shutdown. :)=0A=0A-=0AHenador Titzoff ________________________________ Message 5 _____________________________________ Time: 05:31:56 AM PST US From: Henador Titzoff Subject: Re: AeroElectric-List: iPad charger? Eric, as you can see, there's quite a bit of interest in your iPad charger. Not sure what switching IC you will use, but I woild like to see an automotive charger that provides two USB outputs. The ones I've used are flakier than hell, and I'm starting a 6,000 mile USA round trip in December. I want to take my Garmin 496 so I can capture breadcrumb trails to send home to mama. That will require one 12 cigarette socket and two USB outputs. Anyone know of something reliable that exists today? Henador Titzoff -------------------------------------------- On Thu, 10/10/13, Eric Page wrote: Subject: Re: AeroElectric-List: iPad charger? To: "aeroelectric-list@matronics.com" Date: Thursday, October 10, 2013, 5:48 PM --> AeroElectric-List message posted by: Eric Page Rumen: No worries. I think I've seen three Erics on the List! I haven't seen the charger you've got, but I'm sure it's a switcher. They all are. Getting enough current at 5V to rapid-charge an iPad through a linear regulator fed with 14V would make an 18-watt heater! Marvin: Panel mounted and hard wired is exactly my plan. Nice, neat installation and zero hassle during use. Michael and Earl: Thanks for your interest; I'll add you to my contact list. Cheers, Eric do not archive AeroElectric-List Email Forum - - MATRONICS WEB FORUMS - List Contribution Web Site - -Matt Dralle, List Admin. ________________________________ Message 6 _____________________________________ Time: 05:41:00 AM PST US From: Peter Pengilly Subject: Re: AeroElectric-List: B-787 Li-Ion battery story continues I think Boeing have got themselves into a difficult place - possibly involving considerable politics. Its clear the original decision was based on saving weight - I don't know what the value per pound would have been but I project I was involved with not too long ago was up to $10,000 per pound saved and was talking of going to $50K - that's development $$ spent to save one pound. A Li battery was probably very attractive and a low cost weight save. But the technology maturity assessment now seems to be inaccurate. It has become clear that the actual in service weight saving is negligible with the extra metal work, the maintenance overhead is large, and the reputational impact for all concerned is is difficult to quantify. The big picture view seems to say fit a NiCad for a quiet life, I'm guessing that most airlines would accept a small weight increase (on a 260,000 lb airframe) - is the weight saving equation now around the other way? But what are the internal Boeing political implications of such a change? We'll probably never know ... Its an interesting saga to watch from the outside and try to guess what is going on! Peter On 11/10/2013 12:35, James Kilford wrote: > Some interesting stuff in there Bob. Two things in particular stood out: > > 1) Are customers going to have the appetite for the increase in useful > load when compared with the risk associated with the new battery > technology, when such benign alternatives exist? > > 2) What is the wisdom of making things so different for ground crew on > one Boeing aeroplane? It seems to be tempting fate by making ground > operations different. In my line of work the non-functional > requirements are often the ones that bite you, and perhaps this is a > similar case. > > James > > > On 10 October 2013 04:03, Robert L. Nuckolls, III > > > wrote: > > > > > I've published a compendium of articles on the B787 > battery story at: > > http://tinyurl.com/ag2e9xk > > but in particular, there's a recent addition that > adds a lot of useful information > > http://tinyurl.com/lyc5845 > > > Bob . . . > > =================================== > - > ric-List" > target="_blank">http://www.matronics.com/Navigator?AeroElectric-List > =================================== > MS - > k">http://forums.matronics.com > =================================== > e - > -Matt Dralle, List Admin. > t="_blank">http://www.matronics.com/contribution > =================================== > > > * > > > * ________________________________ Message 7 _____________________________________ Time: 07:06:56 AM PST US From: "earl_schroeder@juno.com" Subject: Re: AeroElectric-List: iPad charger? I have taken a 12V to 110VAC device and used a multiple outlet adapter for power on long trips. Messy but workable. Earl ---------- Original Message ---------- Eric, as you can see, there's quite a bit of interest in your iPad charger. Not sure what switching IC you will use, but I woild like to see an automotive charger that provides two USB outputs. The ones I've used are flakier than hell, and I'm starting a 6,000 mile USA round trip in December. I want to take my Garmin 496 so I can capture breadcrumb trails to send home to mama. That will require one 12 cigarette socket and two USB outputs. Anyone know of something reliable that exists today? Henador Titzoff -------------------------------------------- do not archive ________________________________ Message 8 _____________________________________ Time: 07:07:17 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Congratulations, Bob! At 07:18 AM 10/11/2013, you wrote: >Bob, > >Many people have chimed in about your contract job with Cessna. I >want to congratulate you, too. I think you are a great asset in the >OBAM world and will help Cesspool become Cessna again. Certainly Cessna, (like EVERY other manufacturer of goods and services) has suffered from the stubbing of technological and marketing toes. But such is the nature of success/failure in the free-market exchange of value. They are, after all, managed by mere mortals. I think the measure of an institution is defined not so much by the nature of their blunders but by what is done repair damage to stature and to prevent them from happening again. My boss has identified some shortcomings in his domain that he has asked me to consider and then apply skills specific to mitigation of those weaknesses. I cannot speak for other bosses throughout the Cessna hierarchy but this one seems to have a solid grip on his mission and design goals. >Such jobs require a lot of time. I can't help but think that your AE >activities will slow down, since there's only so many femtoseconds >in a day. It's okay. Do a great job at Cessna and whatever time you >have left is good enough for us. Hopefully your home lab activities >will be supplanted by Cessna lab activities, which means you will be >helping both entities. Actually, my work there probably won't have much to do with the hammer-n-tongs implementation of their technology. Those folks are WAaaaayy out ahead of anything we did at Beech on the airplanes. Now . . . If I could round up all those guys I used to work with at the Targets Division, I'm confident that they would fit nicely into the herding of bytes and electrons at Cessna. My greatest attention will be on communication. The use of English words in a manner that describes design goals and requirements as accurately and unambiguously as their words in C describe functions in their airplanes. >If contracting pays off big time, perhaps you will find it in your >heart to send us all $100 so we can get through the shutdown. :) Understand. Dr. Dee was bullied from her chairmanship of the psychology department at Bethany College. She has been looking at replacement opportunities for the last 6 months or so. Just yesterday she received a phone call from her 1st choice of opportunities that not only got her a healthy raise but relieved her of much of the $overhead$ associated with the Bethany job. She loved the work with Bethany students and the honorable amongst her colleagues. However, tariffs levied on her finances and the attacks on her integrity made it seem as if she were paying to work there! The AeroElectric-List came into being and grew during my full time tenure at Beech . . . I'm not expecting that pressures on my 'spare' time will be any greater at Cessna. In fact, the efficient conversion of time to cash gives us the opportunity to exercise the principals of Spontaneous Order to allocation of time. I'll be able to hire some maintenance and upgrade work on the house instead of making my own sawdust. You guys should have seen Dr. Dee yesterday. She got up on the roof and cleaned some gutters before patching some leaks at the joints. Scared the @#^#$ out of me, but she was grin'n ear-to-ear when she got down with the job done. I'm hanging new gutters on the other end of the house today. I thank you all for the kind thoughts and wishes. Compared with two months ago we are now more optimistic for the future than ever. I'm running low on R12 books. Need to get the next revision done and printed. Bob . . . ________________________________ Message 9 _____________________________________ Time: 07:18:18 AM PST US From: Subject: Re: AeroElectric-List: iPad charger? Eric- yes, it is a switcher allright, judging by its size. I am going to subject the critter to some harsh testing before I use it on a 24 V bus. It didn't smoke the first time I used it. The question is how to safely protect equipment these things power - would a fast fuse suffice ? Wondering if something like ebay item 321224237532 could do the job reliably (need just to add a panel USB receptacle). Add me please as well to your contact list. Rumen ---- Eric Page wrote: ============ Rumen: No worries. I think I've seen three Erics on the List! I haven't seen the charger you've got, but I'm sure it's a switcher. They all are. Getting enough current at 5V to rapid-charge an iPad through a linear regulator fed with 14V would make an 18-watt heater! Marvin: Panel mounted and hard wired is exactly my plan. Nice, neat installation and zero hassle during use. Michael and Earl: Thanks for your interest; I'll add you to my contact list. Cheers, Eric do not archive ________________________________ Message 10 ____________________________________ Time: 07:19:04 AM PST US Subject: AeroElectric-List: Re: iPad charger? From: "Eric M. Jones" I've made one of these 10-37V input, variable output 5A linear chargers for a customer. I don't like switch mode power supplies where they can be avoided due to the unknowns of RFI/EMI. Better quality switchers CAN be found. I might be persuaded to make a run of these in about a month. -------- 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=410314#410314 Attachments: http://forums.matronics.com//files/5a_avr_850.pdf ________________________________ Message 11 ____________________________________ Time: 07:23:36 AM PST US From: Subject: Re: AeroElectric-List: Congratulations, Bob! Congratulations from me too, Bob. Cessna just added an excellent asset. Rumen do not archive ---- "Robert L. Nuckolls wrote: ============ At 07:18 AM 10/11/2013, you wrote: >Bob, > >Many people have chimed in about your contract job with Cessna. I >want to congratulate you, too. I think you are a great asset in the >OBAM world and will help Cesspool become Cessna again. Certainly Cessna, (like EVERY other manufacturer of goods and services) has suffered from the stubbing of technological and marketing toes. But such is the nature of success/failure in the free-market exchange of value. They are, after all, managed by mere mortals. I think the measure of an institution is defined not so much by the nature of their blunders but by what is done repair damage to stature and to prevent them from happening again. My boss has identified some shortcomings in his domain that he has asked me to consider and then apply skills specific to mitigation of those weaknesses. I cannot speak for other bosses throughout the Cessna hierarchy but this one seems to have a solid grip on his mission and design goals. >Such jobs require a lot of time. I can't help but think that your AE >activities will slow down, since there's only so many femtoseconds >in a day. It's okay. Do a great job at Cessna and whatever time you >have left is good enough for us. Hopefully your home lab activities >will be supplanted by Cessna lab activities, which means you will be >helping both entities. Actually, my work there probably won't have much to do with the hammer-n-tongs implementation of their technology. Those folks are WAaaaayy out ahead of anything we did at Beech on the airplanes. Now . . . If I could round up all those guys I used to work with at the Targets Division, I'm confident that they would fit nicely into the herding of bytes and electrons at Cessna. My greatest attention will be on communication. The use of English words in a manner that describes design goals and requirements as accurately and unambiguously as their words in C describe functions in their airplanes. >If contracting pays off big time, perhaps you will find it in your >heart to send us all $100 so we can get through the shutdown. :) Understand. Dr. Dee was bullied from her chairmanship of the psychology department at Bethany College. She has been looking at replacement opportunities for the last 6 months or so. Just yesterday she received a phone call from her 1st choice of opportunities that not only got her a healthy raise but relieved her of much of the $overhead$ associated with the Bethany job. She loved the work with Bethany students and the honorable amongst her colleagues. However, tariffs levied on her finances and the attacks on her integrity made it seem as if she were paying to work there! The AeroElectric-List came into being and grew during my full time tenure at Beech . . . I'm not expecting that pressures on my 'spare' time will be any greater at Cessna. In fact, the efficient conversion of time to cash gives us the opportunity to exercise the principals of Spontaneous Order to allocation of time. I'll be able to hire some maintenance and upgrade work on the house instead of making my own sawdust. You guys should have seen Dr. Dee yesterday. She got up on the roof and cleaned some gutters before patching some leaks at the joints. Scared the @#^#$ out of me, but she was grin'n ear-to-ear when she got down with the job done. I'm hanging new gutters on the other end of the house today. I thank you all for the kind thoughts and wishes. Compared with two months ago we are now more optimistic for the future than ever. I'm running low on R12 books. Need to get the next revision done and printed. Bob . . . ________________________________ Message 12 ____________________________________ Time: 07:26:13 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: iPad charger? At 07:10 AM 10/11/2013, you wrote: > >Add me to the list - I already have the panel spot and fuse slot identified. > >Is there an 'easy' way to determine externally whether a given >cheapo or high price cig plug usb charger is the switcher/linear >regulator type or the type that has some chance of working for >awhile? 'Easy' being defined as with a multi-meter or perhaps even >a quick peek inside. Interesting question. While all the discussion has been centered on I-Pad supplies, the problems are not limited to the I-Pad. If somebody had told me 10 years ago that the whole world will run out of a USB port in the future, I would have scoffed. But here we are. At first the USB port was a serial data specialty connection that just happened to include a 5VDC source that would support a half-amp or so of load by some accessory . . . like a mouse or a keyboard. But the mobile phone industry jumped on that 5v source as a means by which batteries could be charged. This prompted a huge growth in 5v power conditioners from wall-warts, cigar-lighter adapters and a boost in power output ratings of USB ports on appliances. I have a USB hub on my desktop that comes with a 5v, 2A wall wart intended to augment the 5v, 1/2A capability of the port on the computer. Now comes the I-Pad and similar devices with screens that need power. Dr. Dee has a Kindle that charges with a 5v wall-wart . . . or USB port on a computer . . . but charging times are long (6+ hours) and these chargers will not support simultaneous charging and operation of the device. I found a 5v 2A wall wart that will both charge and power her Kindle. The key feature is to identify a power source that offers several times the current carrying ability of the run-of-the-mill adapters that have served us well with mobile phones and MP3 players over the past ten years. My gut feeling is that the contemporary 5v adapters that are failing are simply being taxed beyond their design ratings. JUST BECAUSE the thing plugs into a USB mini or micro port doesn't mean that it was ever intended to supply 5 to 10 watt power demands of the new devices. I've never seen a cigar lighter adapter where the nameplate rating exceeded 600 mA (3 watts). I suspect that most are not rated for even that much. I have ordered some 5v, 3A current limited, voltage regulated step-down converters that will accept up to 33 volts of DC input. I'll test these on the bench and then craft a project that will offer a row of USB connectors (DC power only) and a wide range of DC input voltages with the design goal of grunting the greater demands of contemporary devices for 5v power while paying due diligence to noise issues. Those who are interested in measuring demands and qualifying their adapters could build adapter harnesses that would permit a multimeter view of both current demand and supply voltage under load. Bob . . . ________________________________ Message 13 ____________________________________ Time: 07:30:20 AM PST US From: Subject: Re: AeroElectric-List: Re: iPad charger? Yes Eric, the linear 24->19 V PS you made for me works beautifully. Rumen ---- "Eric M. Jones" wrote: ============ I've made one of these 10-37V input, variable output 5A linear chargers for a customer. I don't like switch mode power supplies where they can be avoided due to the unknowns of RFI/EMI. Better quality switchers CAN be found. I might be persuaded to make a run of these in about a month. -------- 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=410314#410314 Attachments: http://forums.matronics.com//files/5a_avr_850.pdf ________________________________ Message 14 ____________________________________ Time: 07:37:42 AM PST US From: Peter Pengilly Subject: Re: AeroElectric-List: Congratulations, Bob! Good luck, sir! I have always found that the English language, in either the Queen's or US dialect, was a remarkably poor tool for such a task. Its a challenge to which we must all pay particular heed as the alternatives are not very attractive. Peter On 11/10/2013 15:03, Robert L. Nuckolls, III wrote: > My greatest attention will be on communication. The > use of English words in a manner that describes design > goals and requirements as accurately and unambiguously > as their words in C describe functions in their airplanes. ________________________________ Message 15 ____________________________________ Time: 08:00:34 AM PST US From: "earl_schroeder@juno.com" Subject: Re: AeroElectric-List: iPad charger? Another item to throw into the mix: The iPad cable is more than 'just' a cable. If you slide down the sleeve on the connector that plugs into the mini iPad you will find a circuit board containing a bunch of components. Buying a 'cheap' replacement cord from eBay will probably charge the mini but the new iOS upgrade will pop up a warning message informing you it may not.. The 'wall-mart' 110VAC is not the cause of the warning.. I have tried them from three different suppliers with the same results. Only the original cord mutes the warning. I've read somewhere that the charging rate of the iPad is also controlled by the cord. Buyer beware... ;) Earl >>Now comes the I-Pad and similar devices with screens that need power. Dr. Dee has a Kindle that charges with a 5v wall-wart . . . or USB port on a computer . . . but charging times are long (6+ hours) and these chargers will not support simultaneous charging and operation of the device. My gut feeling is that the contemporary 5v adapters that are failing are simply being taxed beyond their design ratings. JUST BECAUSE the thing plugs into a USB mini or micro port doesn't mean that it was ever intended to supply 5 to 10 watt power demands of the new devices. I've never seen a cigar lighter adapter where the nameplate rating exceeded 600 mA (3 watts). I suspect that most are not rated for even that much. Bob . . . << ________________________________ Message 16 ____________________________________ Time: 08:36:43 AM PST US Subject: AeroElectric-List: Re: Charge battery thru Ground Power Jack From: "jonlaury" user9253 wrote: > This is a catch 22 situation. A smart battery charger will not turn on and start charging a battery unless it first sees a battery connected. And the aircraft ground power circuit will not turn on unless it first sees ground power connected. > Even if a battery maintainer was able to energize the aircraft ground power contactor, that contactor might consume all of the maintainer output. The maintainer might not have enough energy left to charge or maintain the aircraft battery. > I do not see a simple solution to this problem. > There is an error in the schematic. The wire coming out of the top of the OV module should connect to the top of contactor coil, not the bottom of the coil. Bad things could happen if wired as drawn. > Joe Joe, thanks for having my back on the OVM wiring. Got that corrected on the schematic. In exploring Charles' idea of a manual switch, intuitively I thought that drawing power from the battery while trying to charge it might mess up the charging side of things. But what about attaching a 12 v wall wart supply to the positive of the GPJ to provide the necessary current to close the contactor and light the indicator lamp? Upon contactor closure, the batt maitainer would sense battery 12.5v (+/-) and supply the necessary V+ to charge the batt. The fly in the ointment that I can see is that the higher voltage of the batt would takeover the current demands of the contactor and lamp and we're back to square one. UNLESS... the charger can provide enough amperage for both contactor demand and battery demand now that the connection to the batt has been accomplished. I think I may be chasing my tail. John Read this topic online here: http://forums.matronics.com/viewtopic.php?p=410329#410329 ________________________________ Message 17 ____________________________________ Time: 09:34:43 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Charge battery thru Ground Power Jack > >In exploring Charles' idea of a manual switch, intuitively I thought >that drawing power from the battery while trying to charge it might >mess up the charging side of things. Truly 'smart chargers' will tolerate this. For example: http://tinyurl.com/mzzselv Here, a load applied during a sustaining state the charter went to work to grunt the load and stayed in the top-off mode. It returned to the sustaining mode when the load was removed. A still heavier load would have overwhelmed the charger's ability to grunt the load and no doubt the voltage would have sagged. But recovery after removal of load would have been the same. I cannot speak to this capability in other maintainers without tests. > But what about attaching a 12 v wall wart supply to the positive > of the GPJ to provide the necessary current to close the contactor > and light the indicator lamp? Upon contactor closure, the batt > maitainer would sense battery 12.5v (+/-) and supply the necessary > V+ to charge the batt. The fly in the ointment that I can see is > that the higher voltage of the batt would takeover the current > demands of the contactor and lamp and we're back to square one. > UNLESS... the charger can provide enough amperage for both > contactor demand and battery demand now that the connection to the > batt has been accomplished. >I think I may be chasing my tail. Why not simply provide a ground maintenance connector for the battery? Take a 5A fuse from your battery bus to any handy connector situated for easy access in the hangar. Plug your maintainer into this jack while parked. But even before that, what is the perceived value of 'plugging-in'? RG batteries exhibit very low self discharge rates . . . and those rates are temperature dependent. A battery stored in a hangar over the winter would probably start the engine next spring. Plugging- in between flights during the flying season probably doesn't add much to the utility or service life of the battery. But assume you are plugged-in. Assume further that the charger-maintainer is in the same league as the Schumacher 1562 series devices. Hitting the battery with some load for ground ops while the charger is attached will not chase the charger into the weeds; proper charging/maintaining of the battery will resume when the load is removed. Bob . . . ________________________________ Message 18 ____________________________________ Time: 09:37:45 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Cover of Revision 13 Still looking for suggestions/photos as candidtates for the front cover of Revision 13. Many of you will recall that we had a run-off here on the list to choose from several options on R12. At the moment, there's nothing in the hopper . . . Bob . . . ________________________________ Message 19 ____________________________________ Time: 09:50:20 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: B-787 Li-Ion battery story continues Along that same venue, is the model T Ford really any better than a good horse? Is that new fangled and short lived electric light any better than those nice whale oil lamps we already have? Inquiring minds want to know? Happy Skies, Old Bob Do Not Archive In a message dated 10/11/2013 11:17:36 A.M. Central Daylight Time, peter@sportingaero.com writes: I think Boeing have got themselves into a difficult place - possibly involving considerable politics. Its clear the original decision was based on saving weight - I don't know what the value per pound would have been but I project I was involved with not too long ago was up to $10,000 per pound saved and was talking of going to $50K - that's development $$ spent to save one pound. A Li battery was probably very attractive and a low cost weight save. But the technology maturity assessment now seems to be inaccurate. It has become clear that the actual in service weight saving is negligible with the extra metal work, the maintenance overhead is large, and the reputational impact for all concerned is is difficult to quantify. The big picture view seems to say fit a NiCad for a quiet life, I'm guessing that most airlines would accept a small weight increase (on a 260,000 lb airframe) - is the weight saving equation now around the other way? But what are the internal Boeing political implications of such a change? We'll probably never know ... Its an interesting saga to watch from the outside and try to guess what is going on! Peter ________________________________ Message 20 ____________________________________ Time: 09:53:54 AM PST US Subject: Re: AeroElectric-List: Cover of Revision 13 From: James Kilford How about a mosaic made up of lots of small photos of people's installations? Or perhaps specific detail from people's installations, e.g. a fuse, a regulator, an alternator, etc. In fact, given the name of Aeroelectric Connection... how about they're each of a connection used in an installation, e.g, a crimp, a spade, a lug, a contactor bolt, etc. I'll volunteer to assemble them into one mosaic. Cheers, James On 11 October 2013 17:36, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > > Still looking for suggestions/photos as candidtates > for the front cover of Revision 13. Many of you will > recall that we had a run-off here on the list to > choose from several options on R12. At the moment, > there's nothing in the hopper . . . > > > Bob . . . > > ________________________________ Message 21 ____________________________________ Time: 09:55:39 AM PST US Subject: Re: AeroElectric-List: iPad charger? From: Eric Page That would be my recommendation too. Get a Y-splitter for your cigarette lighter socket. Plug the Garmin into one side and a small 110V inverter into the other. Use the OEM wall-wart USB chargers that came with your portables. As Earl said, messy but functional. Eric On Oct 11, 2013, at 2:02 PM, "earl_schroeder@juno.com" wrote: > > > I have taken a 12V to 110VAC device and used a multiple outlet adapter for power on long trips. Messy but workable. Earl > > ---------- Original Message ---------- > > > > Eric, as you can see, there's quite a bit of interest in your iPad charger. Not sure what switching IC you will use, but I woild like to see an automotive charger that provides two USB outputs. The ones I've used are flakier than hell, and I'm starting a 6,000 mile USA round trip in December. I want to take my Garmin 496 so I can capture breadcrumb trails to send home to mama. That will require one 12 cigarette socket and two USB outputs. Anyone know of something reliable that exists today? > > Henador Titzoff > > -------------------------------------------- > > do not archive > > > > > > > > > > > > > > ________________________________ Message 22 ____________________________________ Time: 09:58:04 AM PST US Subject: Re: AeroElectric-List: B-787 Li-Ion battery story continues From: Eric Page All true. And GS Yuasa hasn't come out smelling of roses either! Eric do not archive On Oct 11, 2013, at 5:40 AM, Peter Pengilly wrote: > I think Boeing have got themselves into a difficult place - possibly invol ving considerable politics. > > Its clear the original decision was based on saving weight - I don't know w hat the value per pound would have been but I project I was involved with no t too long ago was up to $10,000 per pound saved and was talking of going to $50K - that's development $$ spent to save one pound. A Li battery was prob ably very attractive and a low cost weight save. But the technology maturity assessment now seems to be inaccurate. > > It has become clear that the actual in service weight saving is negligible with the extra metal work, the maintenance overhead is large, and the reput ational impact for all concerned is is difficult to quantify. The big pictur e view seems to say fit a NiCad for a quiet life, I'm guessing that most air lines would accept a small weight increase (on a 260,000 lb airframe) - is t he weight saving equation now around the other way? But what are the interna l Boeing political implications of such a change? We'll probably never know . .. > > Its an interesting saga to watch from the outside and try to guess what is going on! > > Peter > > On 11/10/2013 12:35, James Kilford wrote: >> Some interesting stuff in there Bob. Two things in particular stood out: >> >> 1) Are customers going to have the appetite for the increase in useful lo ad when compared with the risk associated with the new battery technology, w hen such benign alternatives exist? >> >> 2) What is the wisdom of making things so different for ground crew on on e Boeing aeroplane? It seems to be tempting fate by making ground operation s different. In my line of work the non-functional requirements are often t he ones that bite you, and perhaps this is a similar case. >> >> James >> >> >> On 10 October 2013 04:03, Robert L. Nuckolls, III wrote: olls.bob@aeroelectric.com> >>> >>> I've published a compendium of articles on the B787 >>> battery story at: >>> >>> http://tinyurl.com/ag2e9xk >>> >>> but in particular, there's a recent addition that >>> adds a lot of useful information >>> >>> http://tinyurl.com/lyc5845 >>> >>> >>> >>> >>> Bob . . . >>> >>> ======================== =========== >>> - >>> ric-List" target="_blank">http://www.matronics.com/Navigator?AeroElect ric-List >>> ======================== =========== >>> MS - >>> k">http://forums.matronics.com >>> ======================== =========== >>> e - >>> -Matt Dralle, List Admin. >>> t="_blank">http://www.matronics.com/contribution >>> ======================== =========== > > > ========================== ========= ========================== ========= ========================== ========= ========================== ========= > ________________________________ Message 23 ____________________________________ Time: 10:13:28 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Words as parts At 09:37 AM 10/11/2013, you wrote: > > >Good luck, sir! I have always found that the English language, in >either the Queen's or US dialect, was a remarkably poor tool for >such a task. Its a challenge to which we must all pay particular >heed as the alternatives are not very attractive. Yes, it'a a challenge . . . combined with infinite opportunity. Consider a bucket-load of assorted electronics components, nuts, bolts, enclosures and wire. Then consider the dictionary occupying a place of high stature on stands in thousands of libraries . . . 500,000+ words? These two conglomerates have a common opportunity to craft parts/words into an assembly with value to others. Words can be used to inform, entertain, persuade and injure. So it is with that bucket full of parts. Efficient use of words/parts is an acquired skill. Design goals must be tailored to the work-product's end-use. Design goals for technical writing MAY include elements of information, persuasion and entertainment. That's the stuff I like to do in my writing for the OBAM aviation readers. Technical writing for industry needs to be as trim, direct and invariable as the words used to program a computer or to describe the recipe for a fine dish. It's a different kind of writing. Technical writing often speaks to individuals for whom English is not a first language. This job will dictate that I trade the fun-hat for the information-hat. First to craft a sub-set dictionary of words that have singular meaning and chosen to be the preferred term for that meaning within the discipline. Then study and teach ways to craft the elegant sentence. A task no different than crafting the elegant circuit or software routine. Minimize the variety and numbers of parts/words while meeting design goals. The writing goal is to maximize concentricity of images/ideas between a writer and reader. My task would be no different were the root language anything other than English. Bob . . . ________________________________ Message 24 ____________________________________ Time: 10:18:37 AM PST US Subject: AeroElectric-List: Re: Charge battery thru Ground Power Jack From: "user9253" Any new switching circuit should be carefully analyzed to be sure that the reverse polarity and over-voltage protection is not defeated. Momentarily connecting a 12 volt wall wart is worth a try, or any 12 volt external battery for that matter, to get the battery maintainer operating. Without knowing the characteristics of the battery maintainer, experimenting is required. Consider charging the aircraft battery with a direct connection instead of using the ground power port. This charger from Walmart comes with a cord that attaches permanently to a battery. On the end of the cord is a plug that connects to another plug on the end of the battery charger cord. http://www.walmart.com/ip/Schumacher-Automotive-SpeedCharge-Battery-Maintainer-and-Charger/13005742 The hard part is finding a place on the aircraft to mount the plug so that the charger can be plugged in without opening the cowl. On my RV-12, I plug my battery maintainer into the always hot cigarette lighter outlet inside of the cockpit. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=410341#410341 ________________________________ Message 25 ____________________________________ Time: 10:26:42 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Cover of Revision 13 At 11:53 AM 10/11/2013, you wrote: >How about a mosaic made up of lots of small >photos of people's installations? Or perhaps >specific detail from people's installations, >e.g. a fuse, a regulator, an alternator, etc. >In fact, given the name of Aeroelectric >Connection... how about they're each of a >connection used in an installation, e.g, a >crimp, a spade, a lug, a contactor bolt, etc. > >I'll volunteer to assemble them into one mosaic. > >Cheers, > >James Sounds good to me! But you're going to have to sell it to the List. I'll put any and all offerings into a folder on the website. About a month before I have to finalize the content for printing, we'll have a run-off. Bob . . . ________________________________ Message 26 ____________________________________ Time: 10:32:28 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Charge battery thru Ground Power Jack >This charger from Walmart comes with a cord that attaches >permanently to a battery. On the end of the cord is a plug that >connects to another plug on the end of the battery charger cord. >http://www.walmart.com/ip/Schumacher-Automotive-SpeedCharge-Battery-Maintainer-and-Charger/13005742 Geesh . . . the thing is down to $17. That has to be the greatest bang for the buck of any similar product offered. Bob . . . ________________________________ Message 27 ____________________________________ Time: 10:50:33 AM PST US Subject: Re: AeroElectric-List: Re: iPad charger? From: Sacha Eric Would it be a simple matter to hook up a couple of USB ports to such a device to be able to charge two iDevices simultaneously? Sacha On Oct 11, 2013, at 16:29, wrote: > > Yes Eric, > the linear 24->19 V PS you made for me works beautifully. > Rumen > > ---- "Eric M. Jones" wrote: > > ============ > > I've made one of these 10-37V input, variable output 5A linear chargers for a customer. I don't like switch mode power supplies where they can be avoided due to the unknowns of RFI/EMI. Better quality switchers CAN be found. > > I might be persuaded to make a run of these in about a month. > > -------- > 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=410314#410314 > > > > > Attachments: > > http://forums.matronics.com//files/5a_avr_850.pdf > > > > > > > > > > > > ________________________________ Message 28 ____________________________________ Time: 11:19:15 AM PST US Subject: AeroElectric-List: Relay for Critical Power Feed From: Thomas E Blejwas Bob, In Z-19, you use a diode bridge for critical power feeds. Can a relay be used instead? For example: connect Power Source #1 to terminal 86 and to the critical component; connect Power Source #2 to terminal 30; and 87a to the critical component. If both switched on, power comes from #1, otherwise power comes from whichever is switched on. Seems that this has the advantage of no need for a heat sink and failure of the relay does not prevent power to the critical component. What am I missing? Thanks. Tom Sent from my iPad ________________________________ Message 29 ____________________________________ Time: 11:47:36 AM PST US From: "Gerry van Dyk" Subject: RE: AeroElectric-List: Cover of Revision 13 How about a central image of a nice homebuilt airplane with the images of electrical goodies and installations making a border for it? Gerry -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: October 11, 2013 11:26 AM Subject: Re: AeroElectric-List: Cover of Revision 13 At 11:53 AM 10/11/2013, you wrote: >How about a mosaic made up of lots of small >photos of people's installations? Or perhaps >specific detail from people's installations, >e.g. a fuse, a regulator, an alternator, etc. >In fact, given the name of Aeroelectric >Connection... how about they're each of a >connection used in an installation, e.g, a >crimp, a spade, a lug, a contactor bolt, etc. > >I'll volunteer to assemble them into one mosaic. > >Cheers, > >James Sounds good to me! But you're going to have to sell it to the List. I'll put any and all offerings into a folder on the website. About a month before I have to finalize the content for printing, we'll have a run-off. Bob . . . ________________________________ Message 30 ____________________________________ Time: 02:48:15 PM PST US From: Eric Page Subject: Re: AeroElectric-List: Re: iPad charger? On Oct 11, 2013, at 10:49 AM, Sacha wrote: > Eric > Would it be a simple matter to hook up a couple of USB ports to such a dev ice to be able to charge two iDevices simultaneously? > Sacha Sadly, no. The proprietary charging scheme adopted by Apple prevents rapid- charging from a USB port that doesn't follow their standard. iDevices look f or signaling voltages on the USB data pins to indicate available charging cu rrent. Absent those signals, they assume they're attached to a standard USB data port and limit themselves to 500mA (2.5W) -- that is, if they don't gi ve you the dreaded, "Charging is not supported with this accessory" message. 2.5W won't even keep up with usage for an iPad with the screen at full bri ghtness. The iPad 4 consumes ~8W in this state; the 2-4W of overhead in App le's 10- and newer 12-watt chargers is left for the battery. Eric ________________________________ Message 31 ____________________________________ Time: 04:30:42 PM PST US Subject: Re: AeroElectric-List: Relay for Critical Power Feed From: Eric Page That's a novel idea, Tom. It would work, if you assume that failure of PS#1 always means instantaneous loss of power output. This would immediately de-energize the relay coil and allow feed from PS#2. If, however, PS#1 suffered a slow ramp-down of output voltage (as with a failed alternator leaving a battery to supply the bus), then bus voltage would likely sag below the minimum for operation of the critical component before the relay de-energized. Relay coils exhibit substantial hysteresis; they require a higher voltage to energize than to de-energize. A 12V-rated relay might energize at 9V rising, but not de-energize until 6V falling. A 12V battery would be effectively dead long before the relay opened. This is why the diode bridge works so well. Whichever main bus has the higher voltage supplies the critical bus, and switchover is seamless, with no dropout during the change. I have a bag of automotive relays on the shelf. I'll try to remember to characterize their behavior when I get home on Monday and report back. Eric On Oct 11, 2013, at 11:18 AM, Thomas E Blejwas wrote: > Bob, > > In Z-19, you use a diode bridge for critical power feeds. Can a relay be used instead? For example: connect Power Source #1 to terminal 86 and to the critical component; connect Power Source #2 to terminal 30; and 87a to the critical component. If both switched on, power comes from #1, otherwise power comes from whichever is switched on. Seems that this has the advantage of no need for a heat sink and failure of the relay does not prevent power to the critical component. What am I missing? Thanks. > > Tom ________________________________ Message 32 ____________________________________ Time: 04:59:37 PM PST US Subject: Re: AeroElectric-List: Re: iPad charger? From: Eric Page It's certainly a truism that switchers are noisier than linear regs. I have a switch-mode horror show in my car to charge my phone. It makes the AM radio unlistenable when I plug it in! That said, I've learned through my own product development process just what you suggested: that you *can* make a quiet switcher. Board layout is critical to the effort. If the switched node is kept as small as possible -- preferably short and wide -- so as not to create an unintentional antenna, you've won half the battle. A shielded inductor is a given, and judicious use of snubbers to tame ringing and overshoot bring you closer still. Most remaining noise can be blocked with carefully tuned filtering (thanks, Bob!). The main advantage of switchers, of course, is their efficiency: greater than 85% is common. That means less wasted electrons in capacity-limited applications (admittedly not an issue in a vehicle, as long as the alternator is online) and less heat in many cases. Eric On Oct 11, 2013, at 7:18 AM, "Eric M. Jones" wrote: > I've made one of these 10-37V input, variable output 5A linear chargers for a customer. I don't like switch mode power supplies where they can be avoided due to the unknowns of RFI/EMI. Better quality switchers CAN be found. > > I might be persuaded to make a run of these in about a month. > > -------- > Eric M. Jones > www.PerihelionDesign.com > 113 Brentwood Drive > Southbridge, MA 01550 > (508) 764-2072 > emjones(at)charter.net ________________________________ Message 33 ____________________________________ Time: 06:14:37 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Cover of Revision 13 At 01:47 PM 10/11/2013, you wrote: > > >How about a central image of a nice homebuilt airplane with the images of >electrical goodies and installations making a border for it? You're the artist . . . assemble a composite to propose and we'll add it to the mix of options. The front cover is of pretty high resolution and, of course, 8.5 x 11 inches. So the candidate image would probably want to be something on the order of 8500 pixels wide by 1100 tall. Bob . . . ________________________________ Message 34 ____________________________________ Time: 08:04:58 PM PST US Subject: Re: AeroElectric-List: Cover of Revision 13 From: Sacha > The front cover is of pretty high resolution and, of course, 8.5 x 11 inches. So the candidate image would probably want to be something on the order of 8500 pixels wide by 1100 tall. Theres a missing zero: 8500 x 11000 is what you meant I think ________________________________ Message 35 ____________________________________ Time: 08:12:36 PM PST US Subject: Re: AeroElectric-List: Re: iPad charger? From: Sacha > iDevices look for signaling voltages on the USB data pins to indicate available charging current. Absent those signals, they assume they're attached to a standard USB data port and limit themselves to 500mA (2.5W) Yup. What I was wondering is, suppose you have a 5V supply with the right signaling voltages and plenty of power? Does paralleling two USB ports onto its output work to supply two iPads (or an iPad and fast-charge an iPhone) or does one need some kind of circuit to isolate one from the other? ________________________________ Message 36 ____________________________________ Time: 08:49:49 PM PST US Subject: Re: AeroElectric-List: Cover of Revision 13 From: Bill Here are some sterling examples of what this list, Aero Electric Connection is about, *and *that give a nod to our list-master Matt Dralle at the same time. See: http://alturl.com/jwgiu By the way Bob - I'd like to see something personal that you pick for the cover too. Bill SF bay area On Fri, Oct 11, 2013 at 8:03 PM, Sacha wrote: > > > The front cover is of pretty high resolution and, of course, 8.5 x > 11 inches. So the candidate image would probably want to be something on > the order of 8500 pixels wide by 1100 tall. > > Theres a missing zero: 8500 x 11000 is what you meant I think > > ________________________________ Message 37 ____________________________________ Time: 10:01:06 PM PST US Subject: Re: AeroElectric-List: Re: iPad charger? From: Verso Electronics On Oct 11, 2013, at 8:11 PM, Sacha wrote: > Yup. What I was wondering is, suppose you have a 5V supply with the right signaling voltages and plenty of power? Does paralleling two USB ports onto its output work to supply two iPads (or an iPad and fast-charge an iPhone) or does one need some kind of circuit to isolate one from the other? I can't think of any reason paralleling them wouldn't work, assuming you only want to charge Apple devices. I haven't paralleled the data pins in my design (because I want the ports to be able to charge two different brands of devices simultaneously) but the bulk charging current is shared. Eric ________________________________ Message 38 ____________________________________ Time: 11:36:22 PM PST US From: Fred Klein Subject: AeroElectric-List: EXP 2 Bus workaround Guys...electrical wizards... With full knowledge of my ignorance of all things electric but with only scant knowledge of the challenges which lay ahead, some time ago I purchased an EXP 2 Bus, thinking that having one would simplify many issues and offset some of the novelty inherent with my auto engine conversion, a MPEFIed derivative of a EA81 Subaru built by RAM Performance Aero Engines which is liquid cooled. Aircraft is a Europa XS monowheel which is typically powered w/ a 912S or 914. I've been struggling to layout a circuit diagram which combines the EXP 2 BUS configured for an external solenoid with the dual battery / single alternator diagram Z-19 in the "Connection". I have made a number of decisions which have committed me to the digital world including: - an engine w/ electronic ignition, fuel injection, and an ECU (EC3, Real World Systems) which came w/ the engine, - a digital EMS (EM3, Real World Systems) which "talks" w/ the ECU, - a digital EFIS (Skyview) including moving map, digital terrain, Transponder, COM, and Intercom. By selecting an auto engine conversion, I have committed to: - one alternator, belt driven, - one coolant pump, belt driven, - single spark plug in each cylinder. Additionally, in order to provide redundancy, the engine and control system includes: - dual batteries, presently planned to be Odyssey 680's, - two independent high pressure fuel pumps, each w/ their own filter, - independent back up battery for Skyview, - independent back up battery for stand-alone GPS, Garmin 396, - redundant motherboards (A and B) for the ECU which are toggled from the panel. OK...about the EXP BUS...I've now read many reports (including the VAF threads) which point out its shortcomings...but having spent $550 for it and its companion Indicator Module, and given my inexperience and lack of knowledge of things electrical, I still believe it has a place in my panel, so I hope any critique of what I'm up to doesn't focus on simply getting rid of it. The main problem I'm having with the EXP BUS is that it simply does not have the two 20 amp circuits my engine guy sez are essential...one for the fuel injectors, and one for the coils. On my circuit diagram, I attempt to address it by running those two circuits off an Endurance bus which avoids the EXP BUS entirely. I do use available circuits in the EXP BUS for the ECU, the EMS, and the fuel pumps; these components are also fed from the Endurance bus. I have space on my panel (just above the EXP BUS, and below the Skyview flat screen) for a row of 6 - CB / switches which are presently planned to be: - rocker or toggle between Fuel Pump #1 and Fuel Pump #2, - Endurance Master Switch / 50 amp CB, - Battery #2 ON / OFF, - 20 amp CB for Fuel Injectors, - 20 amp CB for Coils, - spare Attached are pixs of my instrument panel in its present state, and a proposed circuit diagram. I'd be most appreciative of any comments, and particularly those which point our errors or weakness in the diagram. Fred ------------------------------------------------------------------------------------- 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.