[Elecraft] Batteries for K1

[Mike Morrow]

David wrote:

> My K1 has a KBT1 an Internal battery Adapter and I have 4 
> rechargeable batteries at my own. What could be better, buy more 
> rechargeable batteries or a small battery, however bigger than AA 
> batteries, to operate with ?

I have a ten-year-old K1.  I used the KBT1 for about 18 months and
then removed it.  I don't like potential chemical corrosion sources
(batteries) inside my K1, the KBT1 micro-speaker is far inferior to
the standard K1 speaker, and the K1 just looks so much better with
the standard top cover and speaker.

For short-time operation, I use an external 10-cell (arranged 5x2)
AA-cell holder with a six-inch cable going to the K1.  I use NiMH
cells.  But for most situations where the additional weight isn't
objectionable, I use a small 4- to 5-Ah 12-volt sealed-lead-acid
(SLA) battery.  One charge lasts for a long operating interval.
SLA batteries are available in smaller size and capacity, but I've
been happiest with what I described.  I always use rechargeable
batteries of some sort.  

My K1 (with LCD backlight, KNB1, KAT1, KFL1-4) on 10.12 MHz
using a 12-volt DC supply consumes:

On RECEIVE
Low AF Out        60 mA
High AF Out      120 mA
              
On TRANSMIT   
0.1 Watt (min)   280 mA
1.0 Watt         450 mA
2.0 Watt         550 mA
3.0 Watt         650 mA
4.0 Watt         750 mA
5.0 Watt         850 mA
7.0 Watt (max)  1200 mA

The best efficiency seems to be around the 5 Watt output setting.
It is apparent that AA-cell capacity can be depleted fairly quickly.
It pays to have adequate battery capacity.  That's why I like the
5-Ah SLA battery.

73,
Mike / KK5F
K1 S/N 175