Elecraft KX3 Owner's Manual - Manual (Page 23)

23
Internal Batteries
The KX3’s internal battery pack can be used with eight 1.2-1.6 volt AA cells of any type. The pack typically
provides 4-6 hours of casual operation, ideal for field use or as backup during power outages. An internal NiMH
charger is also available (KXBC3, pg. 24).
Opening the Enclosure
To open the enclosure for battery installation, unplug the KXPD3 paddle, then follow the steps below.
1 Loosen all four thumb screws. Then slowly pull the halves apart only about 1/4” (6 mm).
2 Fold open starting at the back. 3 Continue opening. Do not disconnect the flex cable.
When closing the enclosure, be sure not to pinch the battery wires (red and black). If the flex cable
becomes loose at either end, press the connectors back into their sockets.
Recommended Battery Types
Lithium non-rechargeable batteries (e.g., Energizer
L91) are expensive, but their flat discharge curve
and 3 amp-hour rating provides maximum operating
time. In receive, the pack voltage will be about 12
V. In transmit, it will drop to 9-10 V due to the
cells’ high internal series resistance. This voltage is
sufficient for operation at up to 5.0 watts.
NiMH (nickel-metal hydride) batteries have a flat
discharge curve, like lithium cells, but a lower pack
voltage (typically 10 V receive, 8.5-9 V transmit).
Power output of up to 5.0 W is possible, though 3.0
W is recommended to extend battery life. The
advantage of NiMH cells is that they can be
recharged hundreds of times, either externally (in as
little as 1 to 2 hours), or internally (typically 8-12
hours, using the KXBC3 option module).
Alkaline batteries can be used if there’s no other
alternative, but they have several disadvantages.
They should always be used with power output set
to 3.0 W or less to minimize transmit current drain.
They have a steep discharge curve, so the pack will
drop from 12 V to 8 V in about half the time of
Lithium or NiMH cells.
Alkaline batteries are prone to leakage, and
must be removed after use. Damage caused by
battery leakage is not covered by the warranty.