---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 04/27/13: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:58 AM - Dual Batteries (user9253) 2. 09:08 AM - Re: Dual Batteries (Jeff Luckey) 3. 09:56 AM - Re: Dual Batteries (Tim Andres) 4. 12:06 PM - Re: Radio interference (Builder_Bill) 5. 05:08 PM - Re: Failed contactor (Roger & Jean) 6. 07:34 PM - Re: Failed contactor (nuckollsr) 7. 08:20 PM - Re: Dual Batteries (Ed Holyoke) ________________________________ Message 1 _____________________________________ Time: 07:58:58 AM PST US Subject: AeroElectric-List: Dual Batteries From: "user9253" > If you have dual, battery powered, electronic ignition > and single alternator, a second battery will improve system > reliability numbers. Bob, The above quote is from yesterday's AeroElectric daily digest. Did you inadvertently leave the word "NOT" out? Or are you recommending that aircraft with electrically dependent engines with single alternators have dual batteries? Modern AGM batteries are very unlikely to short out. Good workmanship will minimize the danger of an open circuit. In the event of an open battery circuit, the alternator is capable of providing power without the battery. I think that a second battery adds unnecessary weight, cost, and complexity. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399486#399486 ________________________________ Message 2 _____________________________________ Time: 09:08:50 AM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: Dual Batteries Joe, I disagree.- When you add the second battery, you add redundancy to the w hole power train [battery, master solenoid, shunt, wiring, etc].- If any one of those components fails, the associated battery is off-line. Another consideration is how long you can run after an alternator failure. - IIRC, the Odessy-type batteries have about a 20 amp-hour rating which, depending on your buss load, is probably 45-60 minutes of flight time after alt failure.- My personal preference is to have 100% reserve for emergen cy situations. Jeff Luckey --- On Sat, 4/27/13, user9253 wrote: From: user9253 Subject: AeroElectric-List: Dual Batteries >- ---If you have dual, battery powered, electronic ignition >- ---and single alternator, a second battery will improve system >- ---reliability numbers. Bob, The above quote is from yesterday's AeroElectric daily digest.- Did you i nadvertently leave the word "NOT" out?- Or are you recommending that airc raft with electrically dependent engines with single alternators have dual batteries? Modern AGM batteries are very unlikely to short out.- Good workmanship w ill minimize the danger of an open circuit.- In the event of an open batt ery circuit, the alternator is capable of providing power without the batte ry.- I think that a second battery adds unnecessary weight, cost, and com plexity. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399486#399486 le, List Admin. ________________________________ Message 3 _____________________________________ Time: 09:56:56 AM PST US From: Tim Andres Subject: Re: AeroElectric-List: Dual Batteries I think a lot of us, me included tend to over engineer these systems to some extent. Unless you really are going to follow C-130s into hurricanes or similar, Id suggest adding one layer of protection over what your Cessna/Piper had and call it good. Ebus, second alternator OR battery, PMAG or any one thing to add a layer over a bare bones system. If you lose both of those you're one un-lucky guy. Tim ________________________________ From: Jeff Luckey Sent: Sat, April 27, 2013 9:20:40 AM Subject: Re: AeroElectric-List: Dual Batteries Joe, I disagree. When you add the second battery, you add redundancy to the whole power train [battery, master solenoid, shunt, wiring, etc]. If any one of those components fails, the associated battery is off-line. Another consideration is how long you can run after an alternator failure. IIRC, the Odessy-type batteries have about a 20 amp-hour rating which, depending on your buss load, is probably 45-60 minutes of flight time after alt failure. My personal preference is to have 100% reserve for emergency situations. Jeff Luckey --- On Sat, 4/27/13, user9253 wrote: >From: user9253 >Subject: AeroElectric-List: Dual Batteries >To: aeroelectric-list@matronics.com >Date: Saturday, April 27, 2013, 7:57 AM > > > > >> If you have dual, battery powered, electronic ignition >> and single alternator, a second battery will improve system >> reliability numbers. > >Bob, >The above quote is from yesterday's AeroElectric daily digest. Did you >inadvertently leave the word "NOT" out? Or are you recommending that aircraft >with electrically dependent engines with single alternators have dual batteries? >Modern AGM batteries are very unlikely to short out. Good workmanship will >minimize the danger of an open circuit. In the event of an open battery >circuit, the alternator is capable of providing power without the battery. I >think that a second battery adds unnecessary weight, cost, and complexity. >Joe > >-------- >Joe Gores > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=399486#399486 > >http://www.matronics.com/Navigator?AeroElectric-List --> > > > ________________________________ Message 4 _____________________________________ Time: 12:06:42 PM PST US Subject: AeroElectric-List: Re: Radio interference From: "Builder_Bill" Hey Bob, if the noise gets worst at higher alt output, does that implicate a rectifier diode exclusively? I was trying to think if there was another source of noise that would follow the alt load. Bill Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399493#399493 ________________________________ Message 5 _____________________________________ Time: 05:08:26 PM PST US From: "Roger & Jean" Subject: Re: AeroElectric-List: Failed contactor Hi Bob, Just checking to see if you had a chance to open up that failed Main contactor that I sent to you a few weeks back. No urgency, just checking. Thanks, Roger ________________________________ Message 6 _____________________________________ Time: 07:34:49 PM PST US Subject: AeroElectric-List: Re: Failed contactor From: "nuckollsr" Yes I did. Lots of moisture damage. I've got it on my list of things to do when I get back to the office on Monday. Will take some pictures and report to the List Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399510#399510 ________________________________ Message 7 _____________________________________ Time: 08:20:28 PM PST US From: Ed Holyoke Subject: Re: AeroElectric-List: Dual Batteries I'm doing dual Lightspeed Plasma 3 on my RV. I chose to run each directly off a separate PC680 with a fuselink. Either battery can be run on the main buss, or on the ebuss which also has a diode feed from the main. The 680 is rated at 17ah and my ebuss minimum comfortable load will be about 4 amps plus 2 more amps for the ignitions. Assuming day VFR, if I turn off one both battery contactors and have one battery supporting the ebuss, I should be able to run for about 3 plus hours while keeping the second battery in reserve except for the one amp I was drawing for the other ignition. That should leave me about 13 -14ah with which to run out my fuel with at least one ignition assured. This also assumes that I have tested the batteries recently and know how much they will really do at low draw rate. Putting a backup alternator on top of all that seems a little over the top, but maybe I'll add it before I undertake a Bahamas trip or something like that. The option I didn't select was for one battery and two alternators. Seems viable, and is lighter, but I just liked the separate feeds to the ignitions and being able to start from one battery and have no brownout problems with EFIS run from the other one. I will need to remember to close the contactor on the non starting battery after engine start so it will charge. I don't see that as a problem, just a post start checklist item. Push comes to shove, I can use both batteries for starting, too. If I do need both to start, it's time to do another capacity check and maybe replace one or both batteries. Ed Holyoke On 4/27/2013 9:56 AM, Tim Andres wrote: > I think a lot of us, me included tend to over engineer these systems > to some extent. Unless you really are going to follow C-130s into > hurricanes or similar, Id suggest adding one layer of protection over > what your Cessna/Piper had and call it good. Ebus, second alternator > OR battery, PMAG or any one thing to add a layer over a bare bones > system. If you lose both of those you're one un-lucky guy. > Tim > > > ------------------------------------------------------------------------ > *From:* Jeff Luckey > *To:* aeroelectric-list@matronics.com > *Sent:* Sat, April 27, 2013 9:20:40 AM > *Subject:* Re: AeroElectric-List: Dual Batteries > > Joe, > > I disagree. When you add the second battery, you add redundancy to > the whole power train [battery, master solenoid, shunt, wiring, etc]. > If any one of those components fails, the associated battery is off-line. > > Another consideration is how long you can run after an alternator > failure. IIRC, the Odessy-type batteries have about a 20 amp-hour > rating which, depending on your buss load, is probably 45-60 minutes > of flight time after alt failure. My personal preference is to have > 100% reserve for emergency situations. > > Jeff Luckey > > --- On *Sat, 4/27/13, user9253 //* wrote: > > > From: user9253 > Subject: AeroElectric-List: Dual Batteries > To: aeroelectric-list@matronics.com > Date: Saturday, April 27, 2013, 7:57 AM > > > > > > If you have dual, battery powered, electronic ignition > > and single alternator, a second battery will improve system > > reliability numbers. > > Bob, > The above quote is from yesterday's AeroElectric daily digest. > Did you inadvertently leave the word "NOT" out? Or are you > recommending that aircraft with electrically dependent engines > with single alternators have dual batteries? > Modern AGM batteries are very unlikely to short out. Good > workmanship will minimize the danger of an open circuit. In the > event of an open battery circuit, the alternator is capable of > providing power without the battery. I think that a second > battery adds unnecessary weight, cost, and complexity. > Joe > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=399486#399486 > > http://www.matronics.com/Navigator?AeroElectric-List --> > > > > > * > > > * > * > > > * ------------------------------------------------------------------------------------- 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.