---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 07/19/13: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:18 AM - Re: Battery capacity tester- Why isn't there a flyback diode? (Eric M. Jones) 2. 07:33 AM - Re: Re: Battery capacity tester- Why isn't there a flyback diode? (Roger & Jean) 3. 10:00 AM - Re: Re: Battery capacity tester- Why isn't there a flyback diode? (Robert L. Nuckolls, III) 4. 10:28 AM - Heathrow 787 fire (Robert L. Nuckolls, III) 5. 10:30 AM - Re: Lithium Ferrous Batteries (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:18:27 AM PST US Subject: AeroElectric-List: Re: Battery capacity tester- Why isn't there a flyback diode? From: "Eric M. Jones" There probably should be a "flyback" diode there. Actually I've been searching the antique shops for an AC plug-in clock and haven't been able to find one. This issue of EDN has a plethora of battery-related designs, among which is a similar battery-tester. See attached. http://www.edn.com/design/analog/4368112/Circuit-measures-battery-capacity?elq=e82db0a50e5244e5961468cc2f470404&elqCampaignId=258 ps: The 787 has yet ANOTHER battery problem. Yikes! -------- 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=404929#404929 Attachments: http://forums.matronics.com//files/battery_tester_873.pdf ________________________________ Message 2 _____________________________________ Time: 07:33:22 AM PST US From: "Roger & Jean" Subject: Re: AeroElectric-List: Re: Battery capacity tester- Why isn't there a flyback diode? Actually I've been searching the antique shops for an AC plug-in clock and haven't been able to find one. Walmart has a couple of these clocks in the $10 range. I bought one at my local store recently. Roger ________________________________ Message 3 _____________________________________ Time: 10:00:27 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Battery capacity tester- Why isn't there a flyback diode? At 09:32 AM 7/19/2013, you wrote: > Yes, a coil spike suppressor would e good idea. Should have been there in the first place . . . sorry 'bout that. >Actually I've been searching the antique shops for an AC plug-in >clock and haven't been able to find one. > Walmart has a couple of these clocks in the $10 range. > I bought one at my local store recently. But they are getting harder to find. The AA powered quartz movement has all but totally captured the wall/desk clock market. The cap-tester I photographed last week measures both battery voltage and elapsed time in software. Bob . . . ________________________________ Message 4 _____________________________________ Time: 10:28:26 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Heathrow 787 fire > >ps: The 787 has yet ANOTHER battery problem. Yikes! I've been reading some of the un-journalistic babbling about the Heathrow event. Yes, the ELT was located in the fire zone. Yes, it contains a lithium battery. But . . . The history of this design goes back about 8 years with 6000+ in service. The battery is never 'charged' hence any triggering event for battery failure is limited to electronic failure in the ELT or external environmental effects (temperature, vibration, etc.). The paper, voice and byteprint pundits are not known for their sense of history or technical acumen. A mention of the word 'lithium' in an aviation context has the effect of an overdose of meth. I remain skeptical that the ELT battery is root cause of this event but hopefully, more level headed investigators will ultimately prevail. There is another feature of the 797 construction that I find more disturbing. Look through the collection of videos and pictures for the SFO event. As soon as the wreckage comes to rest people are exiting the front of the aircraft on slides, many carrying their bags. Even videos of trucks spraying water and/or foam are remarkably clear of visible flames. Aftermath pictures show little evidence of active burning outside the fuselage eitehr right or left side. There is no evidence of burn thru from outside. Yet, there are huge holes in the fuselage top which had to be caused by release of combustion energy inside the fuselage. Fortunately, by the time all that stuff was fully involved, the airplane was largely empty of passengers. This offers questions about the combustibility of materials in the cabin. Check the few pictures of the Heathrow event airplane. Once again we see evidence of heat damage to outside of the aircraft no doubt caused by combustion of stuff inside the airplane with convection concentrating effects on the roof of the cabin. No doubt the ELT was burned. Recall that Swissair 111 suffered a cabin fire that started with arcing of wires with damaged insulation but PROPAGATED by combustible materials adjacent to the failed wires. I am reluctant to jump onto the lithium wagon for assigning root cause to this event. Bob . . . ________________________________ Message 5 _____________________________________ Time: 10:30:43 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Lithium Ferrous Batteries At 09:48 PM 7/17/2013, you wrote: Bob, I've been a customer of Pegasus Auto Racing for a few years now. I started out buying silicon radiator hose from them, they sent a catalog and I found quite a few aircraft related items and their prices are certainly no worse than Spruce so if they have the item I need I usually get it from them. This is by way of saying they are a good solid business. When I received their latest catalog I noticed that they are carrying the Ballistic Performance EV02 line of Lithium Ferrous batteries. https://www.pegasusautoracing.com/group.asp?GroupID=BALLISTICEVO2 What I don't get is that they spec them by number of cells. >From my limited understanding I would expect that the 2 cell battery would put out ~3 volts on each cell being something like an A123 size lithium battery of ~1.5 volts. Flying an electrically dependant engine on my trike, the little HKS 700 has CDI ignitions but they are not powered separately like the Rotax, I have been thinking of a winter project of adding one of these: The lithium cells deliver energy at about 3v per cell . . . http://tinyurl.com/la8nhr6 Hence, a 12v battery is made up of an array of 4 cells. Larger capacity batteries will add increments of 4 cells in parallel. https://www.pegasusautoracing.com/productdetails.asp?RecID=9402 as a reserve battery just for the ignition. I don't fly IFR or nights and rarely more than a half hour from an airport so 8 amp hours looks to give me at least an hour of reserve to get me to a safe touch down with power to spare. At 15 oz. the wires to hook it up would almost outweigh the battery. Have you ever heard of them? I've seen this product offered by various vendors for several years. Not heard anything 'unhappy' about them. I note that this series of batteries have multi-conductor service connectors on them. This suggests that they offer a specially maintenance tool for charging and testing the battery., For the guys who are using PC680's this battery; https://www.pegasusautoracing.com/productdetails.asp?RecID=9404 seems to offer a lot of performance for 2.5 lb and the price doesn't reflect the usual "aircraft mark up". Here is the company's web page and I've attached their instructions and warranty information. http://www.ballisticparts.com/products/batteries/batteries.php Does this all make sense or is it so much hokus pokus? Without a doubt, these batteries perform as advertised. So did the batteries in the 787. The uncertainty about this an all lithium products contemplated for use in vehicles is their plug-n-play compatibility with SVLA batteries. Do a google search on 'lithium motorcycle battery' . . . http://tinyurl.com/kpkjqv3 A number of these products feature battery maintenance connectors for attaching a specialized tool. Yet NONE of the advertising hype speaks to the value or requirement for this connector and the tool that attaches there. I think the Boeing 787 battery has become one of the world's most monitored (and pampered) battery with maintenance/monitor wires attached to every cell. Herein lies my discomfort. If these products were truly plug-n-play replacement for Ni-Cad and/or SLVA, then this maintenance connector would not exist, nor anything like a lithium-specific charger. We see a similar thing with battery charging offers from the likes of Schumacher with their battery selector switches labeled SLVA, Flooded, Gel-Cell, Deep Cycle, etc etc. Bottom line is that the electrical systems in our airplanes DO NOT feature mulit-conductor maintenance connectors that mate with the smart connector on this or any lithium product. Nor do our regulators feature any selector switch for tailoring system performance to SVLA, flooded, deep cycle, -OR- LITHIUM batteries. I cannot tell you that I KNOW and UNDERSTAND the suitability of any of these lithium products for use on your airplane. I do see unexplained features unique to the lithium battery manufacturing and marketing that suggests the batteries are not drop-in, plug-n-play replacements for the legacy SLVA battery. I DO know that SVLA batteries have a comforting track record and they do not go into fits of failure or fire when MILDLY abused by the vagaries of conditions encountered in millions of vehicles not the least of which are airplanes. Some years back I was motivated to withhold my recommendation for installing un-modified, internally regulated alternators. So too must I be circumspect about the lithium batteries in airplanes. There was never an argument with a stock automotive alternator's ability to perform as advertised. I DID KNOW and UNDERSTAND their inherent failure modes. Similarly can we expect the lithium products to be as energetic and light weight as they claim. In this instance my reservations are based upon what I DON'T KNOW about the batteries . . . (1) and NOBODY KNOWS about their historical performance in airplanes . . . their history is a tiny fraction of that we understand about SVLA. (2) Should we be considering some new regulator design that plugs into the maintenance connector on these batteries? (3) I do know that early drop-in replacements for SVLA proposed on biz-jets INCLUDED internal battery monitoring and maintenance electronics. (4)If Boeing finds value in doing it, should we adopt the philosophy? Take one of these batteries apart . . . Emacs! . . . and you find something like this inside. Emacs! If the suppliers of lithium products onto my grandson's helicopter find value in perhaps doubling the price of a toy battery to shepherd it's life in the consumer wild, how is it that other lithium products can be offered into operating conditions that are at least as abusive if not more so? In the best of all worlds, somebody would finance an investigative activity into the claims for plug-n-play capabilities of lithium products onto airplanes. At the present state of my knowledge, I haven't got a clue. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.