---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 09/07/21: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:38 PM - Re: Z101 in an RV-10 (Robert L. Nuckolls, III) 2. 07:06 PM - Re: Z101 in an RV-10 (Watzlavick) 3. 07:44 PM - Re: Re: Z101 in an RV-10 (Charlie England) 4. 07:51 PM - Re: Z101 in an RV-10 (Watzlavick) ________________________________ Message 1 _____________________________________ Time: 03:38:29 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z101 in an RV-10 >In the RV-10, the battery and battery contactor are located in the tailcone. >Looking at the schematic, I will need to run a large conductor (probably 2AWG) >forward from the contactor to the starter. 4AWG is fine >My concern is that the "fat wire tie point" for the battery bus, aux bus, >and engine bus will need a second large conductor run forward (my aux and >engine busses have decent loads due to IFR and EFII equipment). This >seems like it will add considerable weight... "second large conductor", "decent loads", "considerable weight" are not quantified. The best decisions are made with calculated data. What are the loads on conductors to those busses from their aux power relays? >The only solution I can imagine would be to leave the battery in the tail >and move the battery contactor forward to the firewall. No. Battery contactors go next to batteries as do the aux power relays. See the (*) symbol on the upstream conductors? >This would leave a long length of unprotected wire Not recommended nor necessary >This might become more clear as I start to actually run wires but >for now it seems less than ideal. Thoughts? You have two aux bus feeders. I suspect 10AWG would be quite sufficient . . . but do the numbers. What are the loads and how long are they? 10AWG is on the order of .04 lb/ft so two 8' runs would add about 10 ounces. An 8' run of 2AWG is right at 2 pounds; 4AWG is about 1.2 pounds. So down-size to 4AWG and add two runs of 10AWG and it's about a wash. Your exact results may vary . . . Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 2 _____________________________________ Time: 07:06:55 PM PST US Subject: AeroElectric-List: Re: Z101 in an RV-10 From: "Watzlavick" I'm also considering Z101 for my RV-10 but I'm concerned about the always hot B-lead from the aux alternator to the rear mounted battery in a crash situation. I see 3 options: 1) add another contactor between the aux alternator and battery, 2) use Z-12 instead, or 3) don't fret about the hot B-lead. I've searched through the archives quite a bit and there doesn't seem to be a good consensus whether having an always hot lead with a rear battery is a really bad idea or not. A different question if I may - With Z-101 and the aux alt off, if the battery contactor fails open (unlikely I know) but the main alternator is still running, the battery would then charge via the diode between the main and Endurance bus assuming that relay is closed. Depending on the battery charge state, It seems possible the charge current could blow the fuseable link between the battery and Endurance bus, taking the battery off line. Seems like a diode is needed between the Endurance bus and battery to prevent that. Or is the battery charge current sufficiently limited? -Robert Read this topic online here: http://forums.matronics.com/viewtopic.php?p=503084#503084 ________________________________ Message 3 _____________________________________ Time: 07:44:19 PM PST US Subject: Re: AeroElectric-List: Re: Z101 in an RV-10 From: Charlie England On 9/7/2021 9:05 PM, Watzlavick wrote: > > I'm also considering Z101 for my RV-10 but I'm concerned about the always hot B-lead from the aux alternator to the rear mounted battery in a crash situation. I see 3 options: 1) add another contactor between the aux alternator and battery, 2) use Z-12 instead, or 3) don't fret about the hot B-lead. I've searched through the archives quite a bit and there doesn't seem to be a good consensus whether having an always hot lead with a rear battery is a really bad idea or not. > > A different question if I may - With Z-101 and the aux alt off, if the battery contactor fails open (unlikely I know) but the main alternator is still running, the battery would then charge via the diode between the main and Endurance bus assuming that relay is closed. Depending on the battery charge state, It seems possible the charge current could blow the fuseable link between the battery and Endurance bus, taking the battery off line. Seems like a diode is needed between the Endurance bus and battery to prevent that. Or is the battery charge current sufficiently limited? > > -Robert The 10ga aux B lead is protected by the 14ga fusible link. I didn't try to read the Z101B notes, but I'd assume that wire sizes for the aux alt assume a smaller alternator (typical B&C, etc vac pad mounted alternator @ ~30A max). The 10ga wire with 14ga fusible link should work for 30A. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 4 _____________________________________ Time: 07:51:16 PM PST US Subject: AeroElectric-List: Re: Z101 in an RV-10 From: "Watzlavick" Good point - after I sent the email, I started looking at charge currents and you're right - it's limited by the alternator output. I guess you could call the lack of a diode there a feature in that it allows the battery to be charged via an alternate path. It also seems like it would provide some load stabilization for the alternator. -Robert Read this topic online here: http://forums.matronics.com/viewtopic.php?p=503086#503086 ------------------------------------------------------------------------------------- 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.