[Elecraft] Off the Grid

[Fred Jensen]

On 3/4/2014 2:41 PM, Paul Grigorieff wrote:
> This might be helpful.

> My K3, on receive, with the KAT500 in-line, the P3, and my massive 70A
> Astron p.s. powering the K3, drew about 20A DC.  Putting the K3 in
> transmit mode, with just under 12W drive (so as not to kick in the 100w
> amp) required about 30A DC.  Boosting the output to 50W drew about 70A
> DC.  Running it "wide open," at 100W out, required about 80A DC.  And
> finally, turning on the KPA-500, with 15W drive to yield 300W out,
> required 150A DC.

Hmmmm ... I power my K3, P3, and KAT500 with a Yaesu 1030A power supply. 
  The KPA500 is plugged into the wall of course so I turned it off.  At 
100W the total current is 21A for a total efficiency of ~40%.  I get 
closer to 50% out of my K2 @ 5W output.  The K3/P3/KAT500 combo drain 
might be 1A in receive, the scale is really cramped that low.  80A at 
12V is 960W for an overall efficiency of ~11%.  That seems awful low to me.

A friend gave me a solar panel with a 12Ah SLAB in it.  I've only had 
the chance to use it with my K2 in one Spartan Sprint [too cold out on 
the deck], but I may do QRPTTF with it at the end of April if I don't do 
a SOTA Summit.  The sun is headed back north but the sun angle is still 
not normal to the panel and looking at the charging current vs the 
average drain when I'm keying the K2 on CW @ 5W, it appears I could send 
all of War and Peace during the day and not drain the battery. :-)

When I'm on the solar panel, I'm essentially "off-the-grid," all the 
energy in the battery is solar.  All the rest of the time, we are 
definitely *on* the grid.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org