[Elecraft] Looking for a good battery/charging system for K1

[Jim Miller KG0KP]

What about bringing along a couple of diodes to use externally to drop the 
excess voltage until your supply batteries have depleated a bit.  Eliminate 
them one at a time as the voltage drops.  Same result of having the 
longevity of the higher voltage supply and no additional strain on the K1.

JMHO (not a K1 owner),
73, de Jim KG0KP

----- Original Message ----- 
From: "Paul Kirley" <pkirley at fuse.net>
To: <elecraft at mailman.qth.net>
Sent: Friday, June 19, 2009 8:37 AM
Subject: [Elecraft] Looking for a good battery/charging system for K1


> Before you reach a decision on battery packs, be sure to read Wayne's Tech 
> Note at
> http://www.elecraft.com/TechNotes/k1_battery_op.htm
>
> Basically, the principle of impedance matching applies to both input and 
> output of a rig.  A DC input mismatch results in waste heat, which is 
> usually not a problem unless the DC is in limited supply, e.g., from a 
> battery.
>
> My particular K1 tends to drift a bit more when its regulators have to 
> dissipate extra DC input voltage as heat.  The second regulators in the K1 
> put out about 6.3V, so an input of 14.3V results in twice as much wasted 
> voltage in the regulators as an input of 10.3V, i.e., four times as much 
> wasted heat to cause more drift.
>
> For battery supplies, I prefer packs of 8 AA NiMH cells.  Alternatively, I 
> use a variable AC supply which I set to 10V (plus an extra 0.3V that 
> doesn't make it to the K1's voltmeter).  Either of these supplies matches 
> my preferred 4W output setting fairly well, according to Wayne's note.
>
> 73, Paul W8TM
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>