[Elecraft] Need suggestion for K1 external rechargeable battery

[Fred Jensen]

On 3/7/2012 6:52 PM, George Averill wrote:
> I have been powering my K1 with a 15 AH battery that I had on hand.
> Much too heavy for a back pack HI!  I'm looking for a small, light
> weight, rechargeable battery.  What AH battery should I be looking
> for if operating at 5W?  Any suggestions?

Hard to beat the LiFePO4 chemistry.  I use an A123 4S1P with my K2. 
Upsides:  Very flat discharge curve, mine starts at about 14V, declines 
to about 12.9 very quickly and pretty much stays there until it's dead, 
at which point the voltage falls very quickly.  Small, mine measures 
about 2 3/4" x 4 1/4" x 1" and weighs less than a pound.  On CW, at 5W, 
with a reasonable duty cycle [calling CQ, tuning, answering] it powers 
my K2 longer than I'm willing to sit on a SOTA summit [7-8 hours].  K2 
RX drain is 280ma, it'll power it RX only for 15-20 hours easy.

Downsides:  They're not exactly cheap, and you need a cell balancing 
charger for them.  I use a CellPro which has programs for every other 
battery known to humankind too.  Be sure to fuse the + power to the 
radio.  These batteries will deliver well over 15C into a short ... 
things get real hot real fast.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org