---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 09/26/08: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:29 PM - A Tale of Two Batteries (Ed Holyoke) ________________________________ Message 1 _____________________________________ Time: 03:29:56 PM PST US From: Ed Holyoke Subject: AeroElectric-List: A Tale of Two Batteries Howdy, I recently bought the West Mountain Radio CBA and did some tests on some old batteries. Here's what I found: Battery 1 came with our airplane and after about 2 years we decided to replace it. It is a Conorde RG-25XC rated at 25 ah. It was removed from the airplane in January of 06 and charged 2 or 3 times since. It mostly just sat. I charged it with a BatteryMINDer at 8 amps and discharged it at 4amps to 10.5v. It tested to 12.1 ah, or about half it's rated capacity. Battery 2 is the same make and model and is the battery which replaced Bat 1 in Jan/06. This battery gave no problems in service until the day that the positive cable chafed through and shorted against a stainless braided brake line in flight. It resulted in a smoke filled cabin and an emergency landing (on airport). When I arrived on the scene an hour and a half later, I moved the brake line away from the cable and measured 5 volts on the battery. Needless to say, the cable has been protected from this ever happening again. The battery was charged overnight (on an ancient non-smart charger) and returned to service. A month or two later, it failed to start the airplane and was changed out for another RG-25 XC. This was all about a year ago. I don't remember if I charged this battery after removal, but it was at 12.66 volts before I charged it for this test. I discharged it at 4 amps to 10.5v. It, surprisingly, came in at 25.4 ah - right at rated capacity. I'm going to swap it back into the airplane long enough to test Battery 3 and see how that one is doing. I also tested a friend's 35 ah Concorde battery which is a year old but hasn't yet seen service at 4 amps to 10.5v and got 37.4 ah out of it. In the meantime, my computer's UPS quit working so I pulled the 8 ah battery out of it and found it to be 5.3v. I extended the leads out of the UPS box and hooked them to Battery 1 and hooked my computer back up to it. The float voltage seems high at 13.72, but I'm not worried about it seeing as how that battery is useless for much else and if it fails at some point, I have another to replace it. Hope I didn't bore Y'all too much, Ed Holyoke ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.