---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 10/21/10: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:15 AM - Re: Ground Power / Tiedown Power Cart (PHILLIPS I) 2. 06:44 AM - Re: Ground Power / Tiedown Power Cart (user9253) 3. 07:10 AM - Re: AUX Battery (user9253) 4. 07:30 AM - Re: AUX Battery (Robert L. Nuckolls, III) 5. 11:12 AM - MGL Avionics - Clip on ferrites for radio noise suppression (AZFlyer) 6. 05:20 PM - Re: MGL Avionics - Clip on ferrites for radio noise suppression (Robert L. Nuckolls, III) 7. 07:07 PM - Voltage Regulator Sense Wire Location (Rick Titsworth) 8. 10:07 PM - Re: Ground Power / Tiedown Power Cart (jerb) ________________________________ Message 1 _____________________________________ Time: 12:15:29 AM PST US Subject: Re: AeroElectric-List: Ground Power / Tiedown Power Cart From: PHILLIPS I Hi I am using a 12volt battery pack with built in inverter but my system is only 12v, http://www.northerntooluk.com/automotive-equipment/battery-chargers-and-cab les/400w-emergency-power-source_2354E.html But it shouldn=92t be too difficult to use two together for your 24v starts , it also come=92s with LED light and tyre pump, Just a idea! Ivor On 20 October 2010 21:44, Ed Gilroy wrote: > Here's a subject I have not seen discussed, as of yet, on the list or in > Bob's Aero-Electric Connection: > > We would like to construct a 12 volt, 24 volt, and 110 volt ground power > cart for powering electrical tools, etc. and for jumping our club airplan es > during the winters here in the wilds of Jersey. We have non-electrified > outdoor tiedown spots. > > It would seem (2) 12 volt automotive batteries in series would be > inexpensive and we would keep them charged via simple 12v solar chargers > mounted on top of our storage shed. The 24V charging/inverting devices ar e > hundreds of dollars. > > So how might such a circuit look to "isolate" the batteries for 12 volt > charging and occasional 120v inverter usage from the 12v side and still > allow on-demand 24/28V "jumping"? > > My thinking says manually isolate the 24v series circuit until I want to > "jump" and just throw a switch to go 24v with everything else physically > disconnected. Or is there a more elegant solution? Idiot proof would be > best, remember these are pilots !!! > > I have thought about this for some months but see no simple solution to > provide this "isolation" function but then I am a BSCS, not an EE. > > Thanks... Ed > > * > =========== =========== =========== =========== > * > > ________________________________ Message 2 _____________________________________ Time: 06:44:48 AM PST US Subject: AeroElectric-List: Re: Ground Power / Tiedown Power Cart From: "user9253" No matter how fool proof you make a dual voltage cart, it is only a matter of time before someone uses the wrong voltage on the their plane. The damage caused will be much greater than the cost of a second cart. So I suggest having two carts, one for 12 volt and one for 24 volt. The carts can be clearly marked. And it should be obvious that the cart with two batteries if for 24 volts. Or how about just having one cart for 12 volts to take care of the majority of aircraft. For the infrequent occasions when 24 volts are required, a spare battery can be connected in series. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=316573#316573 ________________________________ Message 3 _____________________________________ Time: 07:10:15 AM PST US Subject: AeroElectric-List: Re: AUX Battery From: "user9253" > Is there any reason to use a resistor in this configuration? No, I see no reason to use a resistor. If someone else used a resistor, they should be able to explain why. Just because some other builder wired their plane wrong is no reason to do it the same way. There have been arguments on this forum about what type of diode to use to minimize voltage drop. Using a resistor does not minimize voltage drop. If there is a reason for using a resistor, it would be interesting to know how and why it was used. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=316578#316578 ________________________________ Message 4 _____________________________________ Time: 07:30:22 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: AUX Battery At 08:34 PM 10/20/2010, you wrote: >I'm designing my system using a small AUX Battery and single Alt. I >want to charge the aux battery with a Schottkey diode. The AUX >battery will power the avionics during start to prevent brown out >and can be used as clearance delivery and/or a backup bus for the >EFIS/430W GPS/Comm. Others I know of who have done it this way also >used a 50 ohm resistor in series with the diode for reasons no one >can really explain to me. The battery is a small 7ah sealed unit and >I plan to charge it thru the diode and a 7.5 amp fuse. Is there any >reason to use a resistor in this configuration? No. In fact the ideal aux battery charging circuit has a MINIMUM of voltage drop. The Shottky diode offers the closest solid state solution with drops averaging 0.3 to 0.5 volts. You can acquire these devices packaged for user-friendly installations from https://matronics.com/aeroelectric/Catalog/AEC/9001/IM9001-700A.pdf or http://www.periheliondesign.com/powerschottkydiodesfiles/PowerSchottky%20Manual.pdf or loose parts from electronics suppliers of various sorts http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=MBRF40250TGOS-ND Alternatively, you can achieve essentially zero-volts drop for the charging circuit with incorporation of an Aux Battery Management Module that closes a relay between the two batteries only when the alternator is running (bus rises above 13.0 volts). Bob . . . ________________________________ Message 5 _____________________________________ Time: 11:12:49 AM PST US Subject: AeroElectric-List: MGL Avionics - Clip on ferrites for radio noise suppression From: "AZFlyer" Does anybody have first hand experience with the MGL ferrite beads or clip on ferrites for radio noise suppression? They seem to be a good added insurance during installation for EMI suppression for VHF frequencies... and not very expensive. Thanks for your feedback, Mike -------- Mike Miller @ millrml@aol.com 601 XL-B, 3300, Dynon Remember, "the second mouse gets the cheese"! Read this topic online here: http://forums.matronics.com/viewtopic.php?p=316597#316597 ________________________________ Message 6 _____________________________________ Time: 05:20:54 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: MGL Avionics - Clip on ferrites for radio noise suppression At 01:08 PM 10/21/2010, you wrote: > >Does anybody have first hand experience with the MGL ferrite beads >or clip on ferrites for radio noise suppression? > >They seem to be a good added insurance during installation for EMI >suppression for VHF frequencies... and not very expensive. Assuming that the components of any particular suite of avionics were designed and tested for use aboard aircraft, then sprinkling ferrite beads on the bundles to fend of 'gremlins' is about as practical as sprinkling Transorbs on all wires to ward off 'spikes'. There is no such thing as a totally quiet system . . . nor is there a device that is immune from all levels of electro- magnetic pestilence. But in a century of crafting electro- whizzies for airplanes, a very comfortable balance has been achieved between LIMITING the about of garbage a potential antagonist produces paired with designing potential victims for certain degrees of robustness. See: http://www.aeroelectric.com/articles/Philosophy/Whats_all_this_DO160_Stuff_Anyhow.pdf http://www.aeroelectric.com/articles/avmaster.pdf So assuming further that the combination of equipment you're installing has a successful service history in other airplanes when installed per instructions, then likelihood of encountering a noise problem is low. If a noise problem IS discovered, it's almost bound to have roots in (1) poor installation practices or (2) improper design for either the victim or antagonist. RFI beads are the least likely cures for 99+ percent of all noise problems. I've never found them useful on an airplane. I've never heard or read of anyone including such devices in the elegant solution for a system installed aboard any type certificated aircraft. Bob . . . ________________________________ Message 7 _____________________________________ Time: 07:07:15 PM PST US From: "Rick Titsworth" Subject: AeroElectric-List: Voltage Regulator Sense Wire Location Bob, I'm building a 28v Z-14 type dual-battery/dual-bus system with the voltage regulators on the inside of the firewall and both 24v batteries in the tail (for weight/balance considerations). I have 1 LR3C regulator paired with the std Kelly alternator and 1 LS1A regulator paired with a SD-20 alternator. I'm curious, where is the "ideal" location to connect the voltage sense wire (regulator terminal #3) to: a) Routed back to the battery contactors (i.e. near the batteries) b) Anywhere on the power bus(es) near the voltage regulators (i.e. inside of the firewall power bus stud) c) Through the firewall to the alternator d) Doesn't really matter (option B for convenience) I'm assuming I should also set-up/adjust the regulator/alternator output by measuring the voltage back by the batteries. Rick ________________________________ Message 8 _____________________________________ Time: 10:07:39 PM PST US From: jerb Subject: Re: AeroElectric-List: Ground Power / Tiedown Power Cart There are some golf cart batteries that work better for solar charging and can supply a good amount of current for jumping or running inverters. If I recall right cast was around $70 each if I recall right. If your interested I will ping my friend for info on them. There being used by folks living off the grid. A lot of folks are moving to isolated areas in preparation for the coming melt down. jerb At 03:44 PM 10/20/2010, you wrote: >Here's a subject I have not seen discussed, as of yet, on the list >or in Bob's Aero-Electric Connection: > >We would like to construct a 12 volt, 24 volt, and 110 volt ground >power cart for powering electrical tools, etc. and for jumping our >club airplanes during the winters here in the wilds of Jersey. We >have non-electrified outdoor tiedown spots. > >It would seem (2) 12 volt automotive batteries in series would be >inexpensive and we would keep them charged via simple 12v solar >chargers mounted on top of our storage shed. The 24V >charging/inverting devices are hundreds of dollars. > >So how might such a circuit look to "isolate" the batteries for 12 >volt charging and occasional 120v inverter usage from the 12v side >and still allow on-demand 24/28V "jumping"? > >My thinking says manually isolate the 24v series circuit until I >want to "jump" and just throw a switch to go 24v with everything >else physically disconnected. Or is there a more elegant >solution? Idiot proof would be best, remember these are pilots !!! > >I have thought about this for some months but see no simple solution >to provide this "isolation" function but then I am a BSCS, not an EE. > >Thanks... 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