---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 08/11/16: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:10 AM - Re: Re: Wig Wag difficulties (Ed) 2. 06:00 PM - Re: Re: Wig Wag difficulties (Robert L. Nuckolls, III) 3. 09:09 PM - Re: Re: Wig Wag difficulties (Ed) ________________________________ Message 1 _____________________________________ Time: 09:10:17 AM PST US Subject: Re: AeroElectric-List: Re: Wig Wag difficulties From: Ed Howdy Bob, It behaved the same with two different flashers, both EL 13A-2, one Tridon brand the other Novita which appears to be the follow on to Tridon. Maybe 75 ohms would work at 14.4v, but I'm testing in the garage at more like 12.6 with a power supply supporting a battery. When cold, it would sometimes flash for a few and then stop. My guess is that the resistance went up with heat and the current was reduced below the threshold that the flasher would work with. The mountable and heat sinked resistors seem like a good idea. Better than zip tying a hot resistor to the wires for sure. I am not worried about .3A as long as the alternator is running. If it is offline, so will be my main buss and the exterior lighting. My load analysis shows me at 26.4A for night VFR while wigwaging. That's 66% of my 40A alternator capacity. When I designed and built my electrical system, I was planning to use 100w halogens as I have in my other airplane. I've dropped at least 4 amps with the LEDs. I'm also going with LED position/strobe lights for an additional current and weight savings of around 9 amps and 2 1/2 pounds. Ed On 8/10/2016 8:17 PM, Robert L. Nuckolls, III wrote: > At 01:09 PM 8/10/2016, you wrote: >> >> To update where I'm at - I paralleled two 75 ohm, 5w resistors on each >> light and got solid flashing for the 20 minutes that I tested it. The >> resistors are too hot to grip between fingers but not too hot to touch >> lightly. I calc about .33A loss and about 4.16 watts. I might try some >> 50 ohm, 10w resistors which should save me a tenth of an amp and run >> slightly cooler. > > A power resistor running at rated dissipation > will sizzle-spit . . . over 100C surface > temperature. They just do that. > > Your experiment suggests that the flasher > in hand is a bit more demanding of a low- > as-practical resistance to ground on the > OFF lamp. > > I've had a couple builders use resistors > much like this > > *http://tinyurl.com/jroz29g* > > while rated at many more watts . . . if > not mounted to a heat sinking surface, > it too would be too hot to touch. The > handy thing about these guys is that > they're easy to mount on metal surface > that sharply reduces their operating > surface temperature. > > And . . . of course . . . you can change > out the flasher for one more specific > to the application. > > I've opened several versions of those > devices. One particular model was easily > converted to a 4-wire device by cutting > a trace on the board and soldering > on a ground wire to bring out of the case. > > Then the need for 'grounding resistors' > goes away. But if the externally added > resistors is not a source of heartburn, > then I suspect the devices cited above > will do the job . . . and the price is > right. > > > Bob . . . > ________________________________ Message 2 _____________________________________ Time: 06:00:17 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Wig Wag difficulties At 11:05 AM 8/11/2016, you wrote: > >Howdy Bob, > >It behaved the same with two different flashers, both EL 13A-2, one >Tridon brand the other Novita which appears to be the follow on to >Tridon. Maybe 75 ohms would work at 14.4v, but I'm testing in the >garage at more like 12.6 with a power supply supporting a battery. >When cold, it would sometimes flash for a few and then stop. My >guess is that the resistance went up with heat and the current was >reduced below the threshold that the flasher would work with. > >The mountable and heat sinked resistors seem like a good idea. >Better than zip tying a hot resistor to the wires for sure. > >I am not worried about .3A as long as the alternator is running. If >it is offline, so will be my main buss and the exterior lighting. My >load analysis shows me at 26.4A for night VFR while wigwaging. >That's 66% of my 40A alternator capacity. When I designed and built >my electrical system, I was planning to use 100w halogens as I have >in my other airplane. I've dropped at least 4 amps with the LEDs. >I'm also going with LED position/strobe lights for an additional >current and weight savings of around 9 amps and 2 1/2 pounds. > >Ed Good moves. Why would you run wig-wags with an off-line alternator? First, such an occurrence is rare. When it does occur, the design goal is NOT to run everything including the kitchen sink . . . but to keep really USEFUL things running until the airport of INTENDED DESTINATION is in sight. In the earliest days of the implementation of an e-bus, EN ROUTE operating loads were often reduced to 3 amps or less. Certainly, running any form of exterior lighting does not improve significantly on your probability of comfortable termination of flight. Adding the SD-8 in Z-13/8 was a quantum jump in options for EN ROUTE energy consumption. A Plan-B could consider continuous consumption of 8A or more . . . with total independence on the battery's contained energy. Once the airport was in sight, you could fire up everything, kitchen sink and all, for descent and approach to landing. The through process in this particular Failure Modes Effects Analysis is to deduce electrical demands for sustained flight sans main alternator. For myself, the design goal would be to sustain useful/ necessary electro-whizzies, battery only for duration of fuel aboard. I.e. your ELECTRICAL endurance should be equal to or greater than FUEL endurance. In no scenario can I imagine that exterior lighting of any kind is a significant factor in the equation for comfortable termination of flight at airport of intended destination. Back when LongEz was king, a nav/com, transponder, turn-coordinator and minimal panel lighting was easily power up for 4 hours or more by a rather small battery. Your own demands for comfortable EN ROUTE operations without a main alternator are undoubtedly different. It's a good thing to KNOW what they are and then design for meeting those demands for what ever ENDURANCE value you choose . . . perhaps an hour is okay in your book . . . but 3+ hours would not be a bad thing. Energy consumption for exterior lighting doesn't figure into that consideration. Bob . . . ________________________________ Message 3 _____________________________________ Time: 09:09:35 PM PST US Subject: Re: AeroElectric-List: Re: Wig Wag difficulties From: Ed Howdy Bob, Yeah, I had an alternator fail in our 6A and just kept going. I had cap checked the RG-25 battery at the most recent annual using a 4 amp load with a West Mountain Radio CBA, and got 8 hours out of it to 10.5v so I knew that the situation wasn't critical. We flew on for a couple of hours, landed for gas, and flew another hour and a half to our intended destination. Replaced the alternator the next day and still had plenty of pop in the battery for engine start. My new plane will pull a little over 6 amps at minimum load with 2 electronic ignitions, another 2 amps if I don't kill the MFD. I have two PC680s which I will cap check before I fly and at each annual so I will know my endurance. I can power the E-bus with either or both batteries so I can run one and hold the other in reserve if I so choose. Using the Odyssey discharge charts, I'm reading about 5 hrs. endurance, if I'm careful. I may still put on an SD-8 for belt and suspenders. Ed On 8/11/2016 5:58 PM, Robert L. Nuckolls, III wrote: > At 11:05 AM 8/11/2016, you wrote: >> > > > Good moves. Why would you run wig-wags with > an off-line alternator? > > First, such an occurrence is rare. > > When it does occur, the design goal is > NOT to run everything including the kitchen > sink . . . but to keep really USEFUL things > running until the airport of INTENDED DESTINATION > is in sight. In the earliest days of the implementation > of an e-bus, EN ROUTE operating loads were often > reduced to 3 amps or less. > > Certainly, running any form of exterior lighting > does not improve significantly on your probability > of comfortable termination of flight. > > Adding the SD-8 in Z-13/8 was a quantum jump > in options for EN ROUTE energy consumption. A > Plan-B could consider continuous consumption > of 8A or more . . . with total independence > on the battery's contained energy. > > Once the airport was in sight, you could > fire up everything, kitchen sink and all, > for descent and approach to landing. > > The through process in this particular > Failure Modes Effects Analysis is to deduce > electrical demands for sustained flight > sans main alternator. For myself, the > design goal would be to sustain useful/ > necessary electro-whizzies, battery only > for duration of fuel aboard. > > I.e. your ELECTRICAL endurance should be > equal to or greater than FUEL endurance. > In no scenario can I imagine that exterior > lighting of any kind is a significant factor > in the equation for comfortable termination > of flight at airport of intended destination. > > Back when LongEz was king, a nav/com, transponder, > turn-coordinator and minimal panel lighting > was easily power up for 4 hours or more by > a rather small battery. > > Your own demands for comfortable EN ROUTE > operations without a main alternator are > undoubtedly different. It's a good thing > to KNOW what they are and then design > for meeting those demands for what ever > ENDURANCE value you choose . . . perhaps > an hour is okay in your book . . . but 3+ > hours would not be a bad thing. > > Energy consumption for exterior lighting > doesn't figure into that consideration. > > > 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.