Return-Path: Received: from fed1rmmtao12.cox.net ([68.230.241.27] verified) by logan.com (CommuniGate Pro SMTP 4.3c1) with ESMTP id 742428 for flyrotary@lancaironline.net; Thu, 17 Feb 2005 00:33:26 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.27; envelope-from=daveleonard@cox.net Received: from davidandanne ([68.101.147.215]) by fed1rmmtao12.cox.net (InterMail vM.6.01.04.00 201-2131-117-20041022) with SMTP id <20050217053239.SVDT12414.fed1rmmtao12.cox.net@davidandanne> for ; Thu, 17 Feb 2005 00:32:39 -0500 From: "DaveLeonard" To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Re: Battery voltage (was: Racetech RV6A Forced Landing) Date: Wed, 16 Feb 2005 21:32:47 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0044_01C5146F.0EC60130" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 In-Reply-To: Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_0044_01C5146F.0EC60130 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Tracy, again I concur with you. My voltage alarm also goes off at 13.5 volts for the same reason :-) Dave Leonard My voltage alarm is set to go off at around 13.5 volts. This is higher than a fully charged battery. In other words, alarm goes off the instant that the alternator fails. System voltage is about 14.2 volts under normal conditions. It is amazing that people with a complete understanding of how critical electrical system is on an EFI aircraft engine would install an alarm light so small or positioned in such a way that it would not be noticed. I would have to be brain dead not to notice mine. I have had one alternator failure which occurred almost immediately after engine start (this seems to be common). The alarm went off and I taxied back to the hangar. My reaction was not to install another 30 to 40 pounds of electrical stuff on the aircraft. Tracy George, Most of the motorcycles will still show at least 11 volts while cranking and those are small batteries. They will jump back up to at least 12.5 after cranking. I agree that 9.5 volts is almost totally dead for practical purposes. Most battery based systems will have trouble at around 10 volts. Use a backup battery and a changeover system with any electrically based system. The EXP Buss (I think) is sold by the anywhere map people. Makes it very easy to set up a battery backup system and still charge both. I think Eggenfellner also sells them. Good looking product, a good friend has one. For battery info go to the Yuasa web site. In the technical section they have a excellent do's and don'ts of battery operation. There is also a good description of the different battery types and their discharge rates. Good info to know about this VITAL system part! Bill Jepson In a message dated 2/15/2005 11:34:28 PM Pacific Standard Time, lendich@optusnet.com.au writes: Bill, What would you expect the battery to show under starting load. George ( down under) > > > I suspected a charging system failure immediately and checked the > >battery voltage in the SDS monitor. This read 9.5 volts so I knew then that > >we had a charging system failure. At the time, I was not worried about > >making it to an airport, assuming that the alternator had failed just in the > >last few minutes and believing that I had 20-25 minutes of battery power > >remaining. In fact, it is likely that the alternator failed soon after > >takeoff from Springbank but I did not notice signs of the failure until the > >battery was well over half dead. ------=_NextPart_000_0044_01C5146F.0EC60130 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tracy, again I concur with = you.  My=20 voltage alarm also goes off at 13.5 volts for the same reason = :-)
 
Dave Leonard

 
My voltage alarm is set to go off at around 13.5 = volts.  This=20 is higher than a fully charged battery.  In other = words, alarm goes=20 off the instant that the alternator fails.  System voltage is = about 14.2=20 volts under normal conditions.
 
It is amazing that people with a complete understanding of = how=20 critical electrical system is on an EFI aircraft engine would install = an alarm=20 light so small or positioned in such a way that it would not be = noticed. =20 I would have to be brain dead not to notice mine.  I have had one = alternator failure which occurred almost immediately after engine = start (this=20 seems to be common).  The alarm went off and I taxied back to the = hangar.  My reaction was not to install another 30 to 40 pounds = of=20 electrical stuff on the aircraft.
 
Tracy
George,
 Most of the motorcycles will still show at least 11 volts = while=20 cranking and those are small batteries. They will jump back up to at = least=20 12.5 after cranking. I agree that 9.5 volts is almost totally dead = for=20 practical purposes. Most battery based systems will have trouble at = around=20 10 volts. Use a backup battery and a changeover system with any = electrically=20 based system. The EXP Buss (I think) is sold by the anywhere map = people.=20 Makes it very easy to set up a battery backup system and still = charge both.=20 I think Eggenfellner also sells them. Good looking product, a good = friend=20 has one.
 For battery info go to the Yuasa web site. In the = technical=20 section they have a excellent do's and don'ts of battery operation. = There is=20 also a good description of the different battery types and their = discharge=20 rates. Good info to know about this VITAL system part!
Bill Jepson 
 
In a message dated 2/15/2005 11:34:28 PM Pacific Standard Time, = lendich@optusnet.com.au writes:
Bill,
What = would you=20 expect the battery to show under starting load.
George ( down=20 under)

>
> >  I suspected a charging = system=20 failure immediately and checked the
> >battery voltage in = the SDS=20 monitor. This read 9.5 volts so I knew then
that
> >we = had a=20 charging system failure. At the time, I was not worried = about
>=20 >making it to an airport, assuming that the alternator had = failed just=20 in
the
> >last few minutes and believing that I had = 20-25=20 minutes of battery power
> >remaining. In fact, it is = likely that=20 the alternator failed soon after
> >takeoff from = Springbank but I=20 did not notice signs of the failure until
the
> = >battery was=20 well over half dead.
=
 
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