Well,what I came up with is since the Micor supplies arent adjustable,was two silicon diodes in the charging circuit. Drops it to 13.5v then added a contactor,normally closed,with a 125vac coil to connect direct to the batteries during an outage. I will post the results once implemented. 73,Lee
Eric Lemmon wrote: > There is a simple way to have a reliable backup battery system without a > relay. Try this: > > Connect your fused repeater power cable directly to the battery terminals, > without any intervening devices. Connect your power supply to the battery > through a single Schottky diode. Adjust the power supply voltage so that the > battery is floated at its optimum voltage, to account for the small forward > voltage drop across the Schottky diode. I use a Schottky diode because its > forward voltage drop under load is much smaller than that of a silicon diode > and is stable. > > The diode is needed because some power supplies have a tendency to go into a > "crowbar shutdown" mode if the AC input goes away (as during a power failure) > while a DC voltage is maintained at its output by a battery. Such an event > will blow fuses and will almost certainly shut down the repeater. > > Unless the repeater operates almost continuously, the power supply does not > need to match the current draw of the radio during transmit. I have a 50 > watt base station set up this way that has a 26 Ah VRSLA battery floated by > an Astron RS-10 power supply, and it has been 100% reliable through many > power outages. > > I used an International Rectifier #122NQ030R diode, simply because it was > easy to mount on a copper bar that is bolted to the positive terminal of the > power supply. The "R" in the part number indicates reverse polarity, meaning > that the diode terminal screw is the cathode, which is convenient for > attaching the load wire. Here's the datasheet: > http://www.irf.com/product-info/datasheets/data/122nq030.pdf > > 73, Eric Lemmon WB6FLY > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
