[Elecraft] [K3] K3 Off Grid

[Don Wilhelm]

Paul,

It looks like you are ignoring the fact that your power supply is less 
than 100% efficient.
Power into the supply does not equal power out of it.

The readings from your Astron current meter are more realistic for the 
DC Current requirement.

73,
Don W3FPR

On 3/5/2014 3:16 PM, Paul Grigorieff wrote:
> OK, here are some new readings, taken with a Kill-A-Watt power consumption
> meter.  The readings in transmit mode were taken by keying down in CW for a
> few seconds and waiting until the meter reading stabilized.
>
> I have an Astron 70A power supply powering a Rigrunner that then supplies a
> K3, a KAT500, and a PigKnob.  The P3 is plugged into the K3.  There is a
> set of speakers, which draw .06A AC as well.
>
> K3 in RCV mode               .92A AC, or 84W       6 DC  at  14v
> K3 in XMIT, 15W out          2.7A AC, or 240W    17A DC    "
> K3 in XMIT, 50W out          3.7A AC, or 342W    24A DC    "
> K3 in XMIT, 100W out        4.7A AC, or 438W    31A DC    "
>
> How do these look to everyone?  I'd like to get them close to right so that
> I can calculate my battery needs for emergency operation.
>
> Something else I don't understand is the ammeter on the front of the
> Astron.  When the K3 is turned on,  the Astron's meter jumps up about 1A
> DC.  When the K3 is transmitting at 15W, the Astron's meter reads about 7A
> DC.  At 50W transmitted power, it reads 11A DC. And at 100W out, it reads
> 15A DC.  Quite a difference from the measured and computed DC amps listed
> above.  What is going on here?  Simply an innaccurate Astron meter?
>
>