X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 18 Jan 2011 11:49:10 -0500 Message-ID: X-Original-Return-Path: Received: from wolverine.webiness.com ([65.61.103.66] verified) by logan.com (CommuniGate Pro SMTP 5.3.11) with ESMTPS id 4678025 for lml@lancaironline.net; Mon, 17 Jan 2011 20:05:06 -0500 Received-SPF: none receiver=logan.com; client-ip=65.61.103.66; envelope-from=brent@regandesigns.com DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=regandesigns.com; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:Subject:Content-Type; b=fwwSqxD5R28hoJ/UfPc8lUGM8Ac03uUbwL//EW99IeJAdPtx3vOyy8+G7ARQAxSGFbqrvSUwO0DieH7hhzx2ZuX3CtuDDg+nGJMwsJoaDQW0L1myL+yxX5Ni5UoZV+Y6; Received: from 207-170-226-178.static.twtelecom.net ([207.170.226.178] helo=[192.168.1.145]) by wolverine.webiness.com with esmtpa (Exim 4.69) (envelope-from ) id 1Pezzm-0003fJ-EY for lml@lancaironline.net; Mon, 17 Jan 2011 17:04:26 -0800 X-Original-Message-ID: <4D34E718.30601@regandesigns.com> X-Original-Date: Mon, 17 Jan 2011 17:04:24 -0800 From: Brent Regan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: Lithium Batteries Content-Type: multipart/alternative; boundary="------------020904000301040804080500" X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - wolverine.webiness.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - regandesigns.com This is a multi-part message in MIME format. --------------020904000301040804080500 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Lorn writes: <<<< As I look for a replacement for my battery, I ran across (suggested by Wolfgang) the following batteries. http://www.batterystuff.com/batteries/motorcycle/LFX18L1-BS12.html http://www.shoraipower.com/t-faq.aspx At only 2.5 lbs (compared to 25 lbs) and a reasonable $181 price these batteries appear to be a real breakthrough. <>Does anyone have any practical experience with the lithium batteries? >>>> Your airplane battery has two uses, cranking the engine and powering your avionics in the event of an alternator failure. The battery in the above link has a specific energy of 40 watt hours per pound (12V, 6AH, 2.12Lb). Lead Acid (PbSO4) runs 18 watt hours per pound (12V, 20AH, 13.5Lb) so the Lithium batteries have about 2.2 times better specific energy, NOT 10 times. The manufacturer claims the battery has 18 amp hour PbSO4 equivalent rating, in truth it has a 6 amp hour actual rating (see their FAQs), so it will power your avionics for 1/3 the amount of time. In order to have the equivalent energy storage, you would need three of these LiFePO batteries (6.2 Lbs & $550). LiFePO (Lithium Iron Phosphate) is the third(ish) generation of Lithium battery and the least likely to catch fire. It is the preferred chemistry for electric vehicles, including electric aircraft. Older Lithium Polymer are the most dangerous and frequently featured on YouTube videos for their pyrotechnic characteristics. They have a higher specific energy and are frequently used in electric RC models. All Lithium batteries require careful attention and precise charging with a constant current, constant voltage charger, cell temperature monitoring and cell balancing. That said, Space Ship Two uses a Valence LiFePO battery http://www.valence.com/ . My .02, wait for the cost to come down and reliability to go up. Regards Brent Regan --------------020904000301040804080500 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Lorn writes: <<<< As I look for a replacement for my battery, I ran across (suggested by Wolfgang) the following batteries.



At only 2.5 lbs (compared to 25 lbs) and a reasonable $181 price these batteries appear to be a real breakthrough.

<>Does anyone have any practical experience with the lithium batteries? >>>>

Your airplane battery has two uses, cranking the engine and powering your avionics in the event of an alternator failure. The battery in the above link has a specific energy of 40 watt hours per pound (12V, 6AH, 2.12Lb). Lead Acid (PbSO4) runs 18 watt hours per pound (12V, 20AH, 13.5Lb) so the Lithium batteries have about 2.2 times better specific energy, NOT 10 times.  The manufacturer claims the battery has 18 amp hour PbSO4 equivalent rating, in truth it has a 6 amp hour actual rating (see their FAQs), so it will power your avionics for 1/3 the amount of time. In order to have the equivalent energy storage, you would need three of these LiFePO batteries (6.2 Lbs & $550).

LiFePO (Lithium Iron Phosphate) is the third(ish) generation of Lithium battery and the least likely to catch fire. It is the preferred chemistry for electric vehicles, including electric aircraft. Older Lithium Polymer are the most dangerous and frequently featured on YouTube videos for their pyrotechnic characteristics. They have a higher specific energy  and are frequently used in  electric RC models.

All Lithium batteries require careful attention and precise charging with a constant current, constant voltage charger, cell temperature monitoring and cell balancing. That said, Space Ship Two uses a Valence LiFePO battery   http://www.valence.com/ .

My .02, wait for the cost to come down and reliability to go up.

Regards
Brent Regan
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