Re: KR> Backup battery
KRnetters, True confessions time... About seven years ago I flew N191PZ from Seattle to San Diego with an overnight stop at Van Nuys (KVNY) airport in LA. I started up at Van Nuys, taxied out and took off per normal. About 20 minutes into the flight my transponder was reported to be intermittent, right over LA basin. Another 10 minutes went by as I checked everything in the cockpit... except the alternator switch, which had been off the entire time. I do not like feeling nor looking like an idiot, but I sure was one that day. That said, the battery started the plane, ran my radio, transponder, and EFIS displays for 30 minutes airborne and was still pumping out enough juice to fire the engine. The transponder would not hack the lower voltage (Old NARCO AT-50A box = VERY HIGH power requirements), but the rest of the plane was doing just fine. It is up to each pilot/builder to decide whether or not they have sufficient (battery) power on board, but I am proof positive the Corvair motor with a single battery will save your hash even when you are being a moron for 30+ minutes. I am just finishing the build on a Corvair-powered Saberwing and will be going with a single gel-cell battery based on experience. Your mileage may vary. iMs, Zip -Original Message- From: "Flesner via KRnet" Sent: Saturday, August 11, 2018 4:24pm To: "Stef den Boer via KRnet" Cc: "Flesner" Subject: Re: KR> Backup battery On 8/11/2018 5:41 PM, Stef den Boer via KRnet wrote: > 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. > Stef > > +++ Stef, Don't count on getting the full reserve out of the batteries as the voltage will drop as the capacity is use. The lower voltage may not be sufficient for the electronic ignition. Li-ion may hold a better voltage than lead acid but take a look at Li-ph (lithium phosphate?) for safety reasons, much more stable. Someone more educated on the subject might offer better advise. Larry Flesner ___ 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 ___ 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
Re: KR> Backup battery
On 8/11/2018 5:41 PM, Stef den Boer via KRnet wrote: 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. Stef +++ Stef, Don't count on getting the full reserve out of the batteries as the voltage will drop as the capacity is use. The lower voltage may not be sufficient for the electronic ignition. Li-ion may hold a better voltage than lead acid but take a look at Li-ph (lithium phosphate?) for safety reasons, much more stable. Someone more educated on the subject might offer better advise. Larry Flesner ___ 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
Re: KR> Backup battery
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 > : > > > 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 batteryto 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
Re: KR> Backup battery
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 batteryto 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
Re: KR> Backup battery
Paul, I have had a few inflight starts on my engine, all initiated by me. With wind blowing through the prop at ~115+ knots turning an engine in filght is not a problem for most batteries. If a battery is strong enough to crank and start your engine on the ground, it will be able to handle an airborne restart. Mark may have had another reason for having second battery. From memory, that battery was well aft in his plane (weight and balance?) but I may be mistaken on this point. iMs, Zip -Original Message- From: "Ppaulvsk via KRnet" Sent: Friday, August 10, 2018 2:19pm To: "KRnet" Cc: "Ppaulvsk" Subject: KR> Backup battery 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. Paul ViskBelleville Il.618-406-4705 ___ 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 ___ 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
