---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 04/27/17: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:24 PM - Re: TSU'd Usb charger?? (Dj Merrill) 2. 12:49 PM - Re: TSU'd Usb charger?? (Tim Olson) 3. 12:53 PM - fuel gage/sender compatability (ashleysc@broadstripe.net) 4. 01:01 PM - Re: TSU'd Usb charger?? (Rene) 5. 01:13 PM - Re: TSU'd Usb charger?? (Tim Olson) 6. 01:49 PM - Re: Re: Interesting thread on overvoltage event (Jan de Jong) 7. 04:04 PM - Re: fuel gage/sender compatability (Robert L. Nuckolls, III) 8. 05:16 PM - Mitchell fuel gauge. (Tim Yoder) 9. 06:05 PM - Re: Mitchell fuel gauge. (Robert L. Nuckolls, III) 10. 06:53 PM - Re: fuel gage/sender compatability (ashleysc@broadstripe.net) ________________________________ Message 1 _____________________________________ Time: 12:24:10 PM PST US Subject: Re: AeroElectric-List: TSU'd Usb charger?? From: Dj Merrill I've been using this one in the plane and I haven't noticed any interference: https://www.amazon.com/gp/product/B00E1UWA4O/ -Dj -- Dj Merrill - N1JOV - EAA Chapter 87 Sportsman 2+2 Builder #7118 N421DJ - https://deej.net/sportsman/ Glastar Flyer N866RH - https://deej.net/glastar/ ________________________________ Message 2 _____________________________________ Time: 12:49:39 PM PST US Subject: Re: AeroElectric-List: TSU'd Usb charger?? From: Tim Olson I use the exact same thing...SCOSCHE USBC242M, 12 Watts per port (2.4A) 4.8A total. In fact, I probably own about 10 of them with the 2 that were delivered to my house today. I've been using them in both of my aircraft now for at least a couple years with no interference. I don't think I'd buy TSO'd for anything, given that installing a simple lighter/Aux jack is cheap and simple and technology changes so fast. Why spend a couple hundred on a TSO'd box that will probably be obsolete in 3 years anyway. My new audio panels use USB-C ports, and I'm sure within a couple years many other devices will be using USB-C too. Easier to just buy a few new chargers to pop back in the jack. I've said the same thing to people who when building their plane put DVD players in the panel and headrest monitors in the seats. 2 years after it was installed, nobody used DVD anymore. Now you just load the movie on your ipad. Tim On 4/27/2017 2:22 PM, Dj Merrill wrote: > > I've been using this one in the plane and I haven't noticed any > interference: > > https://www.amazon.com/gp/product/B00E1UWA4O/ > > -Dj > ________________________________ Message 3 _____________________________________ Time: 12:53:35 PM PST US From: ashleysc@broadstripe.net Subject: AeroElectric-List: fuel gage/sender compatability Calling all Electronics Wizards; I have a fuel sender installed in each wing that ranges from 10 ohms full to 73 ohms empty. These are hard to get to, and I don't want to change them out unless necessary. I have a dual fuel gauge capable of reading the fuel depth in two tanks. It wants 40 ohms full and 240 ohms empty. Is there some type of "resistance multiplier circuit that I could install between sender and gauge so that they can be used together? Cheers! Stu. ________________________________ Message 4 _____________________________________ Time: 01:01:17 PM PST US From: "Rene" Subject: RE: AeroElectric-List: TSU'd Usb charger?? Tim, quit talking about me. BTW, anybody what some PSengineering video screens? Hate to just throw them out....but nobody on e-bay wanted them. Rene' 801-721-6080 -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Tim Olson Sent: Thursday, April 27, 2017 1:48 PM Subject: Re: AeroElectric-List: TSU'd Usb charger?? I use the exact same thing...SCOSCHE USBC242M, 12 Watts per port (2.4A) 4.8A total. In fact, I probably own about 10 of them with the 2 that were delivered to my house today. I've been using them in both of my aircraft now for at least a couple years with no interference. I don't think I'd buy TSO'd for anything, given that installing a simple lighter/Aux jack is cheap and simple and technology changes so fast. Why spend a couple hundred on a TSO'd box that will probably be obsolete in 3 years anyway. My new audio panels use USB-C ports, and I'm sure within a couple years many other devices will be using USB-C too. Easier to just buy a few new chargers to pop back in the jack. I've said the same thing to people who when building their plane put DVD players in the panel and headrest monitors in the seats. 2 years after it was installed, nobody used DVD anymore. Now you just load the movie on your ipad. Tim On 4/27/2017 2:22 PM, Dj Merrill wrote: > > I've been using this one in the plane and I haven't noticed any > interference: > > https://www.amazon.com/gp/product/B00E1UWA4O/ > > -Dj > ________________________________ Message 5 _____________________________________ Time: 01:13:31 PM PST US Subject: Re: AeroElectric-List: TSU'd Usb charger?? From: Tim Olson HA, funny Rene', I didn't even know that you did that too. :) I know there were quite a few though. If it's an avionics item, it's probably good for a few years. But if it's consumer goods, well, now you know. :) Tim On 04/27/2017 02:59 PM, Rene wrote: > > Tim, quit talking about me. BTW, anybody what some PSengineering video > screens? Hate to just throw them out....but nobody on e-bay wanted them. > > Rene' > 801-721-6080 > ________________________________ Message 6 _____________________________________ Time: 01:49:51 PM PST US Subject: Re: AeroElectric-List: Re: Interesting thread on overvoltage event From: Jan de Jong Bob, thanks a lot for the little experiment. No descending into weeds necessary then. Jan de Jong > In the mean time, I subjected a fully charged ETX36 lithium battery to a 40v, 15A constant current source. > > Didn't take time to record and plot the data but my suspicions were correct, these batteries WILL grunt some level of over-charge current. > > In this experiment, it took several seconds for battery voltage to rise above 16.0 volts. Risks to accessories in an airplane fitted with a PM (read small) alternator and legacy ov protection (16.2v) are small. Indeed, if the system loads are a significant fraction of the alternators maximum output, one might well never trip a legacy ov protection system. ________________________________ Message 7 _____________________________________ Time: 04:04:46 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: fuel gage/sender compatability At 02:52 PM 4/27/2017, you wrote: > > >Calling all Electronics Wizards; >I have a fuel sender installed in each wing that ranges from 10 ohms >full to 73 ohms empty. These are hard to get to, and I don't want to >change them out unless necessary. I have a dual fuel gauge capable >of reading the fuel depth in two tanks. It wants 40 ohms full and >240 ohms empty. Is there some type of "resistance multiplier circuit >that I could install between sender and gauge so that they can be >used together? >Cheers! Stu. Yeah . . . sort of. It's called an 'operational amplifier'. A versatile device that can 'watch' your 10/73 transducer and convert it into a VOLTAGE that mimics the voltages expected across the 40/240 transducer when wired to the mated instrument. What we need is a measure of the transducer bias current that comes out of the instrument when terminated with a 40 ohm resistor, and then with a 240 ohm resistor. Knowing those values will allow us to calculate the resistors that tell the op-amp how to apply its magic. This technique will set the 'endpoints' for the instrument . . . calibration at empty and full. Accuracy of the readings between these values will have to be deduced by filling the tanks with the ship in a pitch attitude consistent with level flight. However, even without calibration, they'll be sufficiently accurate to run your pucker factor up as the needles drop below 1/4 full. Bob . . . ________________________________ Message 8 _____________________________________ Time: 05:16:05 PM PST US From: "Tim Yoder" Subject: AeroElectric-List: Mitchell fuel gauge. I have a Mitchell fuel gauge that read 0-15 lbs and I need it to read 0-7 lbs. My fuel pressure is 3/4 to 3 lbs. Is there a way to to make the gauge indicate half of the value across the 0-15 scale? Mitchell doesn't sell a 0-7 lb gauge. Thanks for any help. ________________________________ Message 9 _____________________________________ Time: 06:05:09 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Mitchell fuel gauge. At 07:15 PM 4/27/2017, you wrote: >I have a Mitchell fuel gauge that read 0-15 lbs and I need it to >read 0-7 lbs. My fuel pressure is 3/4 to 3 lbs. Is there a way to to >make the gauge indicate half of the value across the 0-15 scale? >Mitchell doesn't sell a 0-7 lb gauge. >Thanks for any help. I presume you're talking about gage with and electronic transducer at the engine and a 'specialized' meter at the panel. It's not difficult to re-scale some instruments and tailor them to other signal sources. Here's a loadmeter I used to sell that was made from a generic, 1 milliamp DC instrument. http://www.aeroelectric.com/Catalog/AEC/9007/9007-120-1_Loadmet These were easy to take apart, glue new scale placards onto the existing plate, paint the pointer and put it back together. Then I tailored matching shunts for any value of 100% from 10 to 100Amps. Your task depends on what kind of transducer/ meter configuration you have. It MIGHT be so simple as to reduce the value of a calibration resistor such that the instrument reads 2x real pressure. If I were starting from scratch, I'd get a transducer like this http://tinyurl.com/m2noxox and fit one of the meters like I showed above with a 0-5 psi scale plate. Then, a handful of jelly bean components would provide 5v regulated to power the instrument and set scale-factor + offset to match the transducer. Your Mitchell hardware MIGHT be so adaptable but I can't offer more concrete information without having the parts on the bench to see how they dance with each other. Maybe someone on the List has dug into Mitchell's electro-magic . . . Bob . . . ________________________________ Message 10 ____________________________________ Time: 06:53:33 PM PST US From: ashleysc@broadstripe.net Subject: Re: AeroElectric-List: fuel gage/sender compatability Hi Bob; Thanks for your help. I will get 40 and 240 ohm resistors, make the test, and get back to you with the results via this mode. Cheers! Stu. ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Thursday, April 27, 2017 4:03:16 PM Subject: Re: AeroElectric-List: fuel gage/sender compatability At 02:52 PM 4/27/2017, you wrote: Calling all Electronics Wizards; I have a fuel sender installed in each wing that ranges from 10 ohms full to 73 ohms empty. These are hard to get to, and I don't want to change them out unless necessary. I have a dual fuel gauge capable of reading the fuel depth in two tanks. It wants 40 ohms full and 240 ohms empty. Is there some type of "resistance multiplier circuit that I could install between sender and gauge so that they can be used together? Cheers! Stu. Yeah . . . sort of. It's called an 'operational amplifier'. A versatile device that can 'watch' your 10/73 transducer and convert it into a VOLTAGE that mimics the voltages expected across the 40/240 transducer when wired to the mated instrument. What we need is a measure of the transducer bias current that comes out of the instrument when terminated with a 40 ohm resistor, and then with a 240 ohm resistor. Knowing those values will allow us to calculate the resistors that tell the op-amp how to apply its magic. This technique will set the 'endpoints' for the instrument . . . calibration at empty and full. Accuracy of the readings between these values will have to be deduced by filling the tanks with the ship in a pitch attitude consistent with level flight. However, even without calibration, they'll be sufficiently accurate to run your pucker factor up as the needles drop below 1/4 full. 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