[Elecraft] KX1 7.2V. Performance?

[Phil Wheeler]

If you are after a battery pack which will fit inside the KX1 and 
provide more TX power, I believe Lithium Ion or Lithium Polymer may be 
the best possibilities.  Both provide 3.6 V at end of life and are 
rechargable (with the right charger -- e..g., Maha C-777Plus).  So you 
could use three cells in series ( four might exceed the max of 15 V at 
full charge) of either type .  The trick will be to find them of a size 
and form factor compatible with the KX1's innards.

There are some recent threads re using such cells in the K2.  One 
(12/7/03) starts like this:

> Status Report on the Lithium Polymer batteries in Elecraft K2 project:
>
> The six LiPo cells arrived (3.7v 1600 mah each) from 
> www.BatteriesAmerica.com a couple of days ago. The voltages match 
> within 20mv so I did not worry about matching the stacks. I weighed 
> them, and with (extra) packaging they came to 7.5 ounces (for 11-12v 
> 3200mah capacity). Not bad.
>
> Note that BatteriesAmerica calls these Platinum Polymer rather than 
> Lithium Polymer. This is apparently an advertising ploy. They list 
> them in the RC section. 


73, Phil


drcuthbert@micron.com wrote:

>I can probably build the switching supply in a 1 x 1 x 0.25 inch format. But, I can't find any room in the KX1 for even that. Eveready AA NiMH cells are spec'ed at 2100 maH. The AAA is rated at 700 mAH. Doubling the voltage of the AA cells and accounting for switcher efficiency makes the six AA cells appear to have a capacity of 850 mAH. I wonder if there is room for 10 AAA cells in the KX1?. I am now using an external 1.2AH lead acid battery to run the radio but would the batteries to be self-contained yet give 3 watts of RF. 
>
>The alkalines don't look so good after a closer look at the specs. I can only extract about 2o% of the specified capacity before the voltage drops too low. I will pick up some Lithium's today and give them a try.
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