Return-Path: Sender: (Marvin Kaye) To: lml Date: Tue, 06 May 2003 23:02:57 -0400 Message-ID: X-Original-Return-Path: Received: from vineyard.net ([204.17.195.90] verified) by logan.com (CommuniGate Pro SMTP 4.1b4) with ESMTP id 2335809 for lml@lancaironline.net; Tue, 06 May 2003 21:52:53 -0400 Received: from localhost (loopback [127.0.0.1]) by vineyard.net (Postfix) with ESMTP id 1FF5091C21; Tue, 6 May 2003 21:52:48 -0400 (EDT) Received: from vineyard.net ([127.0.0.1]) by localhost (king1.vineyard.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 04975-01; Tue, 6 May 2003 21:52:47 -0400 (EDT) Received: from direct (fsy22.vineyard.net [66.101.65.22]) by vineyard.net (Postfix) with SMTP id BBE1E91C10; Tue, 6 May 2003 21:52:46 -0400 (EDT) X-Original-Message-ID: <002001c3143b$bf498bc0$16416542@direct> From: "Ted Stanley" X-Original-To: "Mail List Lancair" Subject: Re: Electrical System - Battery Charging X-Original-Date: Tue, 6 May 2003 21:54:24 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Virus-Scanned: by AMaViS at Vineyard.NET Brent Regan has made a good point regarding the "desulfation" of lead acid batteries. There are however reams of information available on the web written by people far more qualified than I on the subject of lead acid battery sulfation. I therefore hesitate to engage in technical debate of the subject. I will however pass on the following which seemed to be the most understandable description of sulfation I could find. Brent is right, BUT there seems to be more to "desulfating" than simple charging. See the item below. The little chargers I'm offering to the LML readership seem to be moderately priced while providing something more than a simple trickle charger. If you have an expensive battery it seems to be a rather small price to pay to extend its life by perhaps a factor of two or so, not to mention avoiding the potential hazards of having a battery whose capacity is minimal at the wrong time. Ted Stanley Lead Acid Battery Cycle: When lead acid batteries discharge, some of the sulfuric acid in the electrolyte is converted to lead sulfate crystals and begin to coat the plates. These crystals interfere with and reduce the capacity of the battery. During recharging operations, sulfate crystals are converted back into sulfuric acid. Most, but not all of the sulfates will be reconverted. These stubborn patches of sulfates will continue to grow and will harden to a class III bond. If unchecked they will grow to the point of battery failure. Sulfation is the failure mode of 84% of lead acid batteries that are discarded yearly. Sulfation on the plates are in three classes in bonding strength to the plates or grades of difficulty to remove. The first grade is removed by recharging. The second grade rapidly dissolves with pulsing. The third or hardest grade (long term sulfation deposits) SLOWLY dissolve with pulsing, as the chemical bonds are really tough to break. Equalization charges, while it accelerates the consumption of the positive plate(s) serve two purposes. First it is a crude and inefficient method of desulfation. Secondly, it creates gassing in the battery. This results in the stirring of electrolyte. Without this stirring, electrolyte can stratify (layer) with the acid settling to the bottom of the case. This condition will cause the bottoms of the plates to be rapidly consumed and severely reduce capacity. An alternative to equalization charging would be to use two different approaches to maintain the battery bank. Desulfating the plates by pulse conditioning will ensure the total removal of class III bonded sulfates. Electrolyte stratification can be eliminated by bubbling (aerating) the batteries using compressed air periodically. The industry standard when using alternate battery maintenance methods is to set the charge controllers to 5% above float voltage levels.