Elecraft • www.elecraft.com • 831-662-8345
E
L E C R A F T
K B T 1
I N T E R N A L B A T T E R Y A D A P T E R
Installation and Operating Instructions
Revision A, June 29, 2001. Copyright © 2001, Elecraft; All Rights Reserved
Introduction
The KBT1 internal battery adapter allows convenient operation of the Elecraft K1 transceiver in the field,
minimizing station size and weight. You can use any AA-cell type, disposable or rechargeable (Alkaline,
NiCd, NiMH, etc.). NiMH cells are preferred because of their relatively flat discharge curve and large
number of recharge cycles. The replacement top cover provides quick access to the batteries--using just two
thumb screws--so it's easy to remove and recharge the batteries using any charger of your choice.
The internal battery can typically handle power settings of 5 watts or more on 80-30 meters, and 4 watts on
the higher bands. However, 2-3 watts is recommended for efficient operation from low voltages (9-10 V for
eight NiMH or NiCd cells). At 3 watts, you'll get roughly 5-10 hours on one charge with 1.6-AH NiMH or
Alkaline cells.
The K1 can operate with complete stability down to an internal battery voltage of about 8.2 volts, thanks to
its low-dropout first regulator and double regulation of the VFO. Battery life is extended near end of charge
by the KBT1's special reverse-polarity protection diode (95SQ015), which is optimized for low voltage
drop (less than 0.2V @ 500 mA).
The kit includes a recessed battery-disable switch, accessible from the top cover. This switch should be set
to the OFF position whenever an external battery is used, as well as when the K1 is transported. Also
included is a slightly smaller replacement speaker. To provide physical stability, the battery holder and
speaker are held firmly in place by a custom aluminum bracket.
Specifications
Battery type
1
Any type of AA cell; NiMH, NiCd, or Alkaline recommended
Weight
2
Approx. 7 oz. (200 g) for 8 NiMH or Alkaline AA cells
Operating time (1600 mA-hr NiMH or standard Alkaline)
Receive only
Over 20 hours (using headphones; 60 mA avg. receive current drain)
Transceive
5-10 hours typ. (3 W transmit, transmit duty cycle 20%)
1
AA-size batteries from some manufacturers may intentionally exceed the standard AA diameter
specification (approx. 0.55" or 14 mm) as a means of slightly increasing capacity. Batteries over this size
should not be used with the KBT1 because they will not fit in the standard AA-cell holder supplied. Radio
Shack NiMH and Alkaline cells (among others) are the correct size.
2
The KBT1 bracket and other parts add less than 1 oz. net because the replacement speaker is lighter than
the original.
