Chuck, It sounds like rather than regulating, you would only need to drop the maximum available voltage to about 14 volts. 3 or 4 series diodes should do the job nicely - and you could easily use a switch to short the diodes after the battery voltage falls below 14 volts. If you limit the maximum current drawn to 1 amp (plenty for the KX1), 1N4007 diodes would do the job, but for higher currents, use diodes rted for your highest expected current draw.
Certainly a regulator would do the job too, but the input-output differential for a regulator must be at least 2 volts for loads in the 1 amp vicinity (LM317 spec) - so while an LM317 could regulate to 14 volts OK with a fully charged battery, the voltage available at the output of the regulator would vary drastically with load as soon as the battery voltage began to fall. 73, Don W3FPR > -----Original Message----- > > > I have a pair of Radio Shack NiCad RC model car batteries 7.2 vdc > 2000 mAh. > I have but them in series and get 16vdc when fully charged. In the past I > have put a 12 volt fan on the batteries until the charged was reduced to > 13.5 vdc and then used them as an external power supply for my > KX1. However > there has to be a better way. Can anyone offer a simple circuit that I > might put together that would provide a regulated 14vdc? > > _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
