At 07:31 PM 01/08/07, you wrote: >Hi, > >New member here. Thanks for allowing me to join. >Our club has acquired some large lead-acid 12v batteries we would like >to use to back up our repeater in emergency situations. Does anyone >know of a good (but simple and inexpensive [we are a very small group >in a very small town]) circuit to accomplish this? Any input would be >appreciated. > >Danny WM5C >Heart Of Texas Ham Operators Group (HOTHOG) >Brady, TX >www.hothog.org
Run the system off the battery, and use a top quality automatic charger to keep the battery up, and make sure the charger is fail safe. You don't need a failed charger boiling and cooking your expensive battery bank. A good reference is Home Power Magazine at www.homepower.com HPM is the bible of the off-the-power-grid community, and the web site has a wealth of information. Plus, they walk the walk as well as talk the talk - the entire magazine is produced with home-made electrical power, and it's edited and published by a ham. They simply do all the layout on computers, then zip up the layout files and email them to the printing / mailing house. They periodically package all the back issues for several years on a CD (one PDF file per monthly magazine). The CDs make searching for a topic easy. More information is on their web site. Another source is the RV community. Many of the tour-bus sized motor homes have 12v battery banks that are charged by a dedicated alternator off the main diesel engine, and some have a small generator that provides AC power when parked. Most have an automatic charger that can keep the battery up when plugged into what they call "shore power" (the term comes from the marine environment). So check out the RV supplier web sites. But take anything you read at a sales site with the proverbial grain of salt - google (and google groups) the manufacturer and model and see if anybody is complaining about it. Mike WA6ILQ
