When I was working on my 2S which was to have a Corvair with electronic ignition and fuel only in the wings and needing a fuel pump I thought of the backup battery situation and I was considering instead of a big battery for starting and a small one as a backup using two smallish 7AH or so batteries with a paralleling solenoid that would be used only for starting. I figured I would diode isolate both alternator feeds to charge the batteries and have one buss for primary ignition and one fuel pump and the second for secondary ignition and the other fuel pump. The buss for electronics, lights, etc. would have a switch so it could run off either battery.
Not sure if this would be the best way to do it or not, but it is an alternative to think about vs. the big battery and small backup battery. My Mustang is using the big/small battery method because it makes sense to me on this particular plane with the backup only needed for avionics, not for critical things like ignition and fuel pump. -------- Original Message -------- Subject: Re: KR> Batteries From: Dj Merrill via KRnet <krnet at list.krnet.org> List-Post: krnet@list.krnet.org Date: Wed, October 14, 2015 11:46 am To: KRnet <krnet at list.krnet.org> Cc: Dj Merrill <deej at deej.net> There is simply no need to have TWO heavy "substantial" batteries in the airplane. If any part of the electrical system is compromised, I'm not silly enough to take off at 2am in the middle of winter in Wyoming. I'll go get a nice warm hotel room and fix the problem in daylight, preferably in a heated hangar.
