Return-Path: Sender: (Marvin Kaye) To: lml Date: Thu, 10 Jul 2003 22:33:11 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m08.mx.aol.com ([64.12.136.163] verified) by logan.com (CommuniGate Pro SMTP 4.1b9) with ESMTP id 2471225 for lml@lancaironline.net; Thu, 10 Jul 2003 18:53:46 -0400 Received: from Sky2high@aol.com by imo-m08.mx.aol.com (mail_out_v36_r1.1.) id q.7a.43dbb218 (4238) for ; Thu, 10 Jul 2003 18:53:44 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <7a.43dbb218.2c3f4877@aol.com> X-Original-Date: Thu, 10 Jul 2003 18:53:43 EDT Subject: Re: [LML] Re: Alternator Sizing X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1057877623" X-Mailer: 9.0 for Windows sub 330 -------------------------------1057877623 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 7/10/2003 5:13:47 PM Central Daylight Time, kycshann@kyol.net writes: do you know? Shannon, OK, you have the right attitude! Your battery may only be useful down to about 9 volts. I know some of my systems fail when they go below 8 volts - Engine monitor shuts down, air-data computer stops working, maybe the radios/GPS pack it in. The starter motor won't work, just in case you need it. The resistance devices, like lights, may continue to work, only dimmer. So, you must not rely on the amp-hour rating of the battery - maybe someone will do some tests - because it is not useful all the way to empty (0 volts). Also, if the charging system is failing or the alternator is not large enough, the battery may already be dragged down by the time the problem is recognized. If the battery is old, it may not have the load life you need. Nuckolls has proposed using 2 17 amp-hour batteries in parallel and replacing one of them every year to help with the age problem. I know that a failed B&C sealed battery will not drag down another - I have done that test. One of the reasons I chose the LASAR electronic ignition is that its backup is not tied to the electrical system - it reverts back to magnetos and, each magneto backs up the other. It is not on the essential bus. I do know some folks running electronic only ignitions with one or two batteries, but only one electrical system bus, one alternator - no backup. An all electric airplane is an interesting challenge what with multiple alternators, bus multiples, interesting switching, but only one engine. That's all I know. Scott Krueger 2003 Air Venture Cup Racer #94 Sky2high@aol.com LNC2 N92EX IO320 Aurora, IL (KARR) PS It's OK, we're not going to get out of this life alive. -------------------------------1057877623 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 7/10/2003 5:13:47 PM Central Daylight Time,=20 kycshann@kyol.net writes:

do you know?

Shannon,

OK, you have the right attitude!

Your battery may only be useful down to about 9 volts. I know som= e=20 of my systems fail when they go below 8 volts - Engine monitor shuts down,=20 air-data computer stops working, maybe the radios/GPS pack it in. The=20 starter motor won't work, just in case you need it. The resistance dev= ices,=20 like lights, may continue to work, only dimmer. So, you must not= =20 rely on the amp-hour rating of the battery - maybe someone will do some test= s -=20 because it is not useful all the way to empty (0 volts).

Also, if the charging system is failing or the alternator is not large=20 enough, the battery may already be dragged down by the time the problem is=20 recognized. If the battery is old, it may not have the load life=20= you=20 need. Nuckolls has proposed using 2 17 amp-hour batteries in=20 parallel and replacing one of them every year to help with the age prob= lem. I=20 know that a failed B&C sealed battery will not drag down another - I hav= e=20 done that test.

One of the reasons I chose the LASAR electronic ignition is that its=20 backup is not tied to the electrical system - it reverts back to magnetos an= d,=20 each magneto backs up the other. It is not on the essential=20 bus.

I do know some folks running electronic only ignitions with one or two=20 batteries, but only one electrical system bus, one alternator - no=20 backup. An all electric airplane is an interesting challenge what with= multiple=20 alternators, bus multiples, interesting switching, but only one engine.

That's all I know.

Scott=20 Krueger
2003 Air Venture Cup Racer #94
Sky2high@aol.com
LNC2 N92EX=20= IO320=20 Aurora, IL (KARR)

PS It's OK, we're not going to get out of this=20 life alive.

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