[Elecraft] My KX3 Battery Approach

[KB9WMJ at wi.rr.com]

Use a better AA battery (3.7V 4.9AH Li-ion):
http://www.ebay.com/itm/181411959514

and battery holder:
http://www.utmfg.com/category/BAT-AA.html

Use 4 of them for 14.8V.

Keith
KB9WMJ


----- Original Message ----- 
From: "hb9brj" <hb9brj at gmail.com>
To: <elecraft at mailman.qth.net>
Sent: Saturday, July 12, 2014 12:30 PM
Subject: Re: [Elecraft] My KX3 Battery Approach


Using 8 internal eneloop cells, I measured battery voltage versus current 
(as
shown on the KX3 display) during RX and different TX pwr levels, created an
Excel scatter chart and fitted a linear trend line. The result: 1.15 Ohms,
R^2 = 0.95.

A single eneloop cell has around 0.035 Ohms of internal resistance (measured
with a 4-connector battery DC resistance meter forcing current pulses thru
the cell under test).

My conclusion: 25% of the 1.15 Ohms are due to the 8 cells, 75% originate in
the battery holder and additional wiring.

Markus HB9BRJ