Hi, I am using also 2 batteries. Both are 7 amps but li-ion. Strong enough for my engine. One is to start the engine with awg 8 and one as a backup for the fuel pump and ignition with awg 12. One batterie gives me 20 min. So if I have a alt failure I have at least 40 min flight time left. Both batties are 1.6 kg including fire box and mount each. If you are interested see http://www.masttotaalconcept.nl/kr2/styled-28/index.html
Stef > Op 11 augustus 2018 om 0:48 schreef Mark Langford via KRnet > <krnet@list.krnet.org>: > > > Paul Visk wrote: > > >> Mark L., I noticed on your wiring schematic on your website you > have a 7 Ahr backup battery. Would you still recommend that size? Is > it large enough to turn the engine over while airborne?I'm at a point > now to where I can pretty much put everything on and do a > weight-n-balance and find out if I need to move my corvair engine > forward to pinpoint my cg.<< > > I never intended or expected that little 7Ah battery to start the > engine. It's there mainly as a backup power supply for fuel pump and > ignition system if the rest of the electrical system goes up in smoke. > It's isolated by a diode to keep it from being compromised by a main bus > melt-down. I do test it by starting the engine on it, which also takes > some electrical load off the main battery while it's spinning the engine > over using the main battery. > > As a data point, my experience has been that a high compression Corvair > with a 54" prop will not restart in a glide if there is no power applied > to the starter, not even if you point it at the ground and run it up to > Vne. The starter circuit won't be the thing that makes your engine > quit, and it's so simple it's difficult to see how it could fail in > flight unless as a victim of collateral damage. Running out of battery > "juice" due to an alternator failure and not noticing the voltage drop > is probably when you'll find a backup battery the most useful. When you > do notice, you should have some idea of how far you can fly before you > kill the backup battery....to avoid unpleasant surprises. You'd > probably want to head for nearest airport with something like a 7Ah > battery. Your Corvair ignition system probably burns 3A at 3000 RPM, > with another amp going to the fuel pump, but that doesn't mean you can > fly almost 2 hours if you are running purely on the 7Ah battery. > > For those who haven't seen it, the electrical system Paul is asking > about is at http://www.n56ml.com/electrical/index.html . > > Mark Langford > m...@n56ml.com > http://www.n56ml.com > > > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/krnet@list.krnet.org/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org Steph and his dad are building the KR-2S see http://www.masttotaalconcept.nl/kr2 _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
