---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 09/15/17: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:14 AM - Dual batteries (robintaylor) 2. 08:39 AM - Re: Dual batteries (Rob Turk) 3. 09:28 AM - Re: Dual batteries (robintaylor) 4. 09:55 AM - Re: Dual batteries (user9253) ________________________________ Message 1 _____________________________________ Time: 08:14:03 AM PST US Subject: AeroElectric-List: Dual batteries From: "robintaylor" In the UK we can now obtain certification to fly home builds under IFR. There are quite strict requirements to achieve this. I want to install a second battery in my RV9 to improve redundancy in the event of an alternator failure. My current battery is a Concorde RG-25XC and I would like the second battery to be an Odyssey PC680. I specify these because I had trouble starting my RV and changed from the Odyssey to the larger capacity Concorde, but I still have the battery and battery holder in the plane. My questions are, Is it OK to run two different AH batteries in parallel. Is it OK to connect the second battery via another solenoid activated by the master switch or is there a better way. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=472905#472905 ________________________________ Message 2 _____________________________________ Time: 08:39:32 AM PST US Subject: Re: AeroElectric-List: Dual batteries From: Rob Turk Just putting batteries in parallel doesn't do much for redundancy. If one develops a short, your backup will be toast too. You may want to consider a further redesign of your electrical system in order to have a true main and backup/essentials battery. Not sure if you are weight constrained, but you could consider an AeroAkku LFP-450D. It's identical in size to the PC680 and weighs 5kg less than a PC680 On 9/15/2017 5:13 PM, robintaylor wrote: > > In the UK we can now obtain certification to fly home builds under IFR. > There are quite strict requirements to achieve this. > I want to install a second battery in my RV9 to improve redundancy in the event of an alternator failure. > My current battery is a Concorde RG-25XC and I would like the second battery to be an Odyssey PC680. > I specify these because I had trouble starting my RV and changed from the Odyssey to the larger capacity Concorde, but I still have the battery and battery holder in the plane. > My questions are, > Is it OK to run two different AH batteries in parallel. > Is it OK to connect the second battery via another solenoid activated by the master switch or is there a better way. > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=472905#472905 > > ________________________________ Message 3 _____________________________________ Time: 09:28:36 AM PST US Subject: AeroElectric-List: Re: Dual batteries From: "robintaylor" Thanks for quick reply. I think I should have said endurance not redundancy. I am trying to do as little as possible and alternator failure is what they consider the main risk so battery endurance is what key. Regarding the batteries, I am light up front because I only have a wooden Cato prop but I will look at the batteries. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=472907#472907 ________________________________ Message 4 _____________________________________ Time: 09:55:06 AM PST US Subject: AeroElectric-List: Re: Dual batteries From: "user9253" Yes, it is OK to put two different sized lead-acid batteries in parallel. It is also OK to to install another solenoid. It could be energized via the master switch. But I would use a separate switch. You might consider installing a backup alternator (Z-13/8) instead of a second battery. Two batteries still have limited endurance. A second alternator gives unlimited endurance, maybe with less weight than adding another battery. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=472908#472908 ------------------------------------------------------------------------------------- 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.