[Elecraft] K2 Low Voltage Cutout

[ac5p at sbcglobal.net]

Hi Fred,  
I would vote for 11.0 or possibly even 10.5 Vdc, if K2 specs say opr range is 10-15V.
Too bad you couldnt borrow an Astro Whattmeter from an RC plane or car enthusiast. With that you could actually measure the Ah demand of the K2 as well as get a good idea of the actual energy and operating time available from the battery.    
73, Mike  AC5P



--- On Fri, 6/10/11, Fred Jensen <k6dgw at foothill.net> wrote:


From: Fred Jensen <k6dgw at foothill.net>
Subject: [Elecraft] K2 Low Voltage Cutout
To: "Elecraft Reflector" <elecraft at mailman.qth.net>
Date: Friday, June 10, 2011, 11:02 PM


I, and a friend, purchased "12V 9.8Ah" Li-ion batteries.  Unfortunately, 
all the specs plus everything on the battery is in Chinese, which more 
unfortunately, the locals at the Sechuan Cuisine can't really decipher. 
  Mike has moved on to an A123, probably a wise move, he hikes up big 
mountains to put them on the air for SOTA.

I've discharged and charged this battery several times, and it really 
appears to be a 7 or so Ah battery.  I know that the input voltage to my 
K2 is regulated down to something quite a bit less, and it really 
doesn't care what I feed it until it gets to some low point.  I'm taking 
it to a SOTA activation at Leviathan Peak over Field Day.

The battery seems to have a more or less linear voltage vs discharge 
curve.  Question:  At what voltage should I consider switching to an 
alternate battery so my K2 doesn't die mid-Q?

Now, ALL ... this is a very specific question, the answer is a number, 
in volts, that's all I'm looking for. This is not intended to start a 
very long thread on battery chemistries, buying from China, better 
batteries, how Elecraft could make the K2 better, interfacing a P3 with 
my K2, KPA500 cables, ... and I really hope you get the idea.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2011 Cal QSO Party 1-2 Oct 2011
- www.cqp.org
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