After performing many hours of battery testing and poring over the data, it became obvious to me that a premium characteristic of a battery is low voltage drop over as much of the discharge curve as possible. Especially with rigs which take advantage of higher battery voltage by allowing higher power levels, as do the Elecraft KX2 and KX3.
By this, I am referring to the internal polarity protection found in almost all rigs. It consists of a diode in series with the positive side of the incoming supply voltage, and forward-biased in correct operation. When the supply is hooked up in reverse polarity, the diode becomes reverse-biased and does not conduct, protecting the internal circuitry from possible destruction. So far, so good, right?
The big problem with this very simple and inexpensive protection circuit is the forward voltage drop in conduction as in normal operation. The better rigs such as the Elecraft KX2 and KX3 use a Schottly diode which has a lower voltage drop than a normal silicon diode. As with a regular silicon diode, this voltage drop is proportional to forward current, i.e. the higher the current, the higher the voltage drop. Here is a chart graphically showing the relationship between