[Elecraft] K3 13.8 VDC power

[Jim Brown]

On Mon,12/22/2014 7:05 AM, Greg Troxel wrote:
> Jim Brown <jim at audiosystemsgroup.com> writes:
>
>> I run a contesting station with two K3s driving power amps with a 10A
>> supply keeping the battery charged during the winter, and solar panels
>> doing it during the summer.
> What do you do about the voltage being 12.5ish instead of 13.8?  Run the
> K3s at reduced power (because of the amps you are doing anyway)?  Don't
> worry about extra IMD?  Use a DC-DC converter to get 13.8V?

Most of my contesting is done either at legal limit, with the K3s 
driving an amp or at QRP. For NAQP, of course, i run 100W. Even at 100W 
and 12.5V the K3 is pretty clean, and at the 40-50W level it takes to 
drive my Ten Tec Titans, even cleaner. The measurements in the link 
below were taken with my usual power setup.

k9yc.com/P3_SpectrumMeasurements.pdf

Someone mentioned using a solar charge controller. I'm using a GV MPPT 
charge controller between my solar panels and the battery. It's RF 
quiet. Most charge controllers make RF noise. GV makes several models 
for different battery types, voltages, and current ratings. They are 
available here. The company also seems to be a good place to buy Li 
batteries.

http://www.batteryspace.com/140w-10a-solar-charge-controller-with-mppt-for-lithium-batteries.aspx

73, Jim K9YC

73, Jim K9YC