What about bringing along a couple of diodes to use externally to drop the excess voltage until your supply batteries have depleated a bit. Eliminate them one at a time as the voltage drops. Same result of having the longevity of the higher voltage supply and no additional strain on the K1.
JMHO (not a K1 owner), 73, de Jim KG0KP ----- Original Message ----- From: "Paul Kirley" <[email protected]> To: <[email protected]> Sent: Friday, June 19, 2009 8:37 AM Subject: [Elecraft] Looking for a good battery/charging system for K1 > Before you reach a decision on battery packs, be sure to read Wayne's Tech > Note at > http://www.elecraft.com/TechNotes/k1_battery_op.htm > > Basically, the principle of impedance matching applies to both input and > output of a rig. A DC input mismatch results in waste heat, which is > usually not a problem unless the DC is in limited supply, e.g., from a > battery. > > My particular K1 tends to drift a bit more when its regulators have to > dissipate extra DC input voltage as heat. The second regulators in the K1 > put out about 6.3V, so an input of 14.3V results in twice as much wasted > voltage in the regulators as an input of 10.3V, i.e., four times as much > wasted heat to cause more drift. > > For battery supplies, I prefer packs of 8 AA NiMH cells. Alternatively, I > use a variable AC supply which I set to 10V (plus an extra 0.3V that > doesn't make it to the K1's voltmeter). Either of these supplies matches > my preferred 4W output setting fairly well, according to Wayne's note. > > 73, Paul W8TM > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
