X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 23 Mar 2007 17:58:39 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-masked.atl.sa.earthlink.net ([209.86.89.68] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1939607 for lml@lancaironline.net; Fri, 23 Mar 2007 16:58:47 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.68; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=HTFopBohnJkSDshI+JOZZoG7DlbE335dNxSm1RlxPl2dDP6Ml3eXFKH7iP+l0EkH; h=Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:X-ELNK-Trace:X-Originating-IP; Received: from [216.57.118.220] (helo=ccaselt) by elasmtp-masked.atl.sa.earthlink.net with asmtp (Exim 4.34) id 1HUqpk-0005xW-Rp for lml@lancaironline.net; Fri, 23 Mar 2007 16:58:01 -0400 X-Original-Message-ID: <00b801c76d8d$f156c380$2512020a@nvidia.com> From: "colyncase on earthlink" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Re: batteries. X-Original-Date: Fri, 23 Mar 2007 13:57:59 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00B5_01C76D53.444FEBB0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3028 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3028 X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da94063ba1de1e2844972d7461a3d763c647b350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 216.57.118.220 This is a multi-part message in MIME format. ------=_NextPart_000_00B5_01C76D53.444FEBB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable With the 2 12 VDC battery setup, the essential bus could be fed from 24 = volts or either of the 12 VDC batteries with the proper switching and = isolation question for the math wiz's: how much does your total MTBF improve when you go from 2 power = subsystems to 3? e.g. suppose the MTBF of a battery in the first two years of its life is = 1 per 10,000 hours Then, assuming for a moment that switches and contactors don't count, = the alternator MTBF is a don't care because it's way higher than the = battery. So you have two batteries, now you are talking at 1/(10,000 * 10,000) = failure rate. Is that good enough? ------=_NextPart_000_00B5_01C76D53.444FEBB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

With the 2 12 VDC battery setup, the essential bus could be fed = from 24=20 volts or either of the 12 VDC batteries with the proper switching and=20 isolation

question for the math wiz's:

how much does your total MTBF improve when you go from 2 power = subsystems=20 to 3?

e.g. suppose the MTBF of a battery in the first two years of its = life is 1=20 per 10,000 hours

Then, assuming for a moment that switches and contactors don't = count, the=20 alternator MTBF is a don't care because it's way higher than the = battery.

So you have two batteries, now you are talking at 1/(10,000 * = 10,000)=20 failure rate.

Is that good enough?

------=_NextPart_000_00B5_01C76D53.444FEBB0--