X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 1 [X] Return-Path: Sender: To: lml Date: Wed, 20 Dec 2006 15:55:37 -0500 Message-ID: X-Original-Return-Path: Received: from smtp4.na.baesystems.com ([63.164.202.13] verified) by logan.com (CommuniGate Pro SMTP 5.1.3) with ESMTP id 1694852 for lml@lancaironline.net; Wed, 20 Dec 2006 12:01:07 -0500 Received-SPF: none receiver=logan.com; client-ip=63.164.202.13; envelope-from=christopher.zavatson@baesystems.com Received: from smtp2.na.baesystems.com (smtp2.na.baesystems.com [10.40.96.13]) by smtp4.na.baesystems.com (8.13.6/8.13.6) with ESMTP id kBKGxxQH006526 for ; Wed, 20 Dec 2006 12:00:06 -0500 (EST) Received: from GLDMS00006.goldlnk.rootlnka.net ([10.44.64.12]) by smtp2.na.baesystems.com (8.13.6/8.13.6) with ESMTP id kBKGxpVD020906 for ; Wed, 20 Dec 2006 11:59:59 -0500 (EST) Received: from gldms10601.goldlnk.rootlnka.net ([10.64.39.18]) by GLDMS00006.goldlnk.rootlnka.net with Microsoft SMTPSVC(6.0.3790.1830); Wed, 20 Dec 2006 11:59:50 -0500 Received: from GLDMS10607.goldlnk.rootlnka.net ([10.64.39.20]) by gldms10601.goldlnk.rootlnka.net with Microsoft SMTPSVC(6.0.3790.1830); Wed, 20 Dec 2006 08:59:49 -0800 X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C72458.40F2D98E" Subject: RE: [LML] Re: electric attitude indicators X-Original-Date: Wed, 20 Dec 2006 08:59:46 -0800 X-Original-Message-ID: In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Re: electric attitude indicators Thread-Index: AccjwHpzn7G9urKpSQSOys9RWnF7+gAg2Tbg From: "Zavatson, Christopher J \(US SSA\)" X-Original-To: "Lancair Mailing List" X-OriginalArrivalTime: 20 Dec 2006 16:59:49.0895 (UTC) FILETIME=[42C00170:01C72458] This is a multi-part message in MIME format. ------_=_NextPart_001_01C72458.40F2D98E Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Hamid, Where did this come from?: <> =20 For the batteries in question here, the very definition of the nominal battery capacity designation is the number of amps that can be discharged for one hour. This definition is provided in the battery manufacturer's literature - see Gill and Concorde websites. Other manufacturers may use a different definition, in particular for energy batteries (long duration, low current applications). Gill does provide capacity data for a 20 hour discharge, but the Ah rating claimed is for the 60 minute discharge. Note that the '25' in Gill 'G-25' does not mean 25 Ah, just as the '25' in Concorde's 'RG-25XC' does not mean 25 Ah. The Gill G-25 is rated at 18 Ah and the Concorde RG-25XC at 24 Ah. =20 Other conditions that apply in order to achieve the battery rated capacity are: -the battery must be new -the test must start with a fully charged battery (manufacturer's procedure must be followed) -the battery must start at the correct temperature (results are sensitive to this) =20 If you only get 45 minutes at a 1C discharge, the battery would fail Concorde's criteria for airworthiness and the battery should be rejected. Concorde uses 80% capacity as their acceptable limit (or 19.2 Ah for the RG25XC). The manufacturers specify how often to perform a capacity test. I do one on my RG25XC at every annual inspection (I mean 'condition inspection'). =20 =20 Chris Zavatson N91CZ 360std www.N91CZ.com ------_=_NextPart_001_01C72458.40F2D98E Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

Hamid,

Where did this come from?:

<<One little detail that most people are not aware of is = that a 35Ah battery is rated to produce that much energy if it is drained over = 20 hours.

….If you drain it at 35A, it will not last one full hour, = likely somewhere

around 45 minutes or less at room temperature = >>

 

For the batteries in question here, the very definition of the = nominal battery capacity designation is the number of amps that can be discharged for = one hour.  This definition is provided in the battery manufacturer’s = literature – see Gill and Concorde websites.  Other manufacturers may use a = different definition, in particular for energy batteries (long duration, low = current applications).  Gill does provide capacity data for a 20 hour = discharge, but the Ah rating claimed is for the 60 minute discharge.  Note = that the ‘25’ in Gill ‘G-25’ does not mean 25 Ah, just as the = ‘25’ in Concorde’s ‘RG-25XC’ does not mean 25 Ah.  The = Gill G-25 is rated at 18 Ah and the Concorde RG-25XC at 24 = Ah.

 

Other conditions that apply in order to achieve the battery = rated capacity are:

-the battery must be new

-the test must start with a fully charged battery = (manufacturer’s procedure must be followed)

-the battery must start at the correct temperature (results are sensitive to this)

 

If you only get 45 minutes at a 1C discharge, the battery would = fail Concorde’s criteria for airworthiness and the battery should be rejected.  Concorde uses 80% capacity as their acceptable limit (or = 19.2 Ah for the RG25XC).  The manufacturers specify how often to perform = a capacity test.  I do one on my RG25XC at every annual inspection (I = mean ‘condition inspection’).

 

 

Chris Zavatson

N91CZ

360std

www.N91CZ.com

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