Elecraft® KX3
KXBC3 NiMH Battery Charger and
Real Time Clock
Installation Instructions
Revision A2, October 19, 2012
opy
C
right © 2012, Elecraft, Inc., All Rights Reserved
Introduction
When the KX3 is equipped with an internal battery using eight AA size NiMH cells, the KXBC3 allows
charging the battery from an external 13.8 VDC supply without removing it from the KX3. The KXBC3 also
provides a Real Time Clock and 24 hour alarm that will automatically power up the KX3.
The internal battery powers the KX3 whenever the external power source is removed, or any time the external
power supply voltage falls below the internal battery voltage. Although any type of AA size cells may be used
for the KX3 internal battery, only NiMH cells rated at 1900 mAH or greater may be charged with the KXBC3.
Installation involves opening the KX3 as if you were changing batteries and then using a screwdriver to remove
the KX3 battery retainer and replace it with the KXBC3 module.
The KXBC3 module and many components inside your KX3 may be damaged by
Electrostatic Discharge (ESD) simply by touching them or a circuit board containing
them unless you take specific steps to prevent such damage. See Preventing
Electrostatic Discharge Damage on page 5 before opening the package containing the
KXBC3 module or working inside your KX3.
Specifications
Battery Compatibility:
Read Charging Batteries on pg 3 for important safety information before charging batteries!
Charging Current:
Charging Temperature:
External Power Supply:
Real Time Clock:
Clock Holdup Time:
CAUTION
NiMH type batteries with a capacity of 1900 mAH or higher.
200 mA
0º C to 40º C.
13.8 V at 500 mA for receive only when charging; approx. 3 amperes when
transmitting and charging.
Time of day (hh:mm:ss) with 24 hour alarm that will wake up the KX3 if
power is off.
≥ 5 minutes. Allows changing the internal batteries without losing time or
alarm setting. The clock continues to run during this time.
1
Setup and Operation
If you haven’t already done so, follow the instructions starting on pg 5 to install your KXBC3 module.
You must have firmware revision 01.22 or later installed in your KX3 for the KXBC3 module to operate as
described here. Check the firmware currently installed as follows:
1. Turn the KX3 on (hold the
BAND- and ATU TUNE switches simultaneously).
2. Hold MENU to enter the menu and then turn the OFS/VFO B knob to select FW REVS.
See Firmware Upgrades in your Owner’s manual for details about how to upgrade your firmware if needed.
Real-Time Clock and Alarm
The real-time clock operates in 24 hour time format and includes an alarm that can be used to wake up the KX3
at a preset time.
Set the real- time clock as follows:
3. Turn the KX3 on (hold the
4. Hold MENU to enter the menu and then turn the OFS/VFO B knob to select TIME.
5. Enter the current time as follows:
Tap
1 and turn the VFO A knob to display the correct hours on the display (the clock displays
times in 24-hour format).
Tap
2 and turn the VFO A knob to display the correct minutes on the display.
Tap 3 and turn the VFO A knob to display the correct seconds on the display.
DISP
6.
Tap
to exit the menu.
BAND- and ATU TUNE switches simultaneously).
The clock will continue to run for up to 5 minutes with the power disconnected so you can change batteries
without needing to reset the time.
Set the alarm as follows:
1. Turn the KX3 on (hold the BAND- and ATU TUNE switches simultaneously).
2. Hold MENU to enter the menu and then turn the OFS/VFO B knob to select ALARM.
3. Enter the time that you want the KX3 to alert you as follows:
Tap
Tap 3 and turn the VFO A knob to the minutes.
Tap 1 and to turn the alarm on. The display will change from OFF to ON.
4. Tap DISP
2 and turn the VFO A knob to set the hour.
to exit the menu.
An asterisk ( ) will appear to the left of the time in the VFO B area of the display indicating that the alarm has
been set.
At the selected alarm time, the KX3 will emit a series of short beeps and the alarm will shut off automatically.
If you have turned the KX3 off, it will turn on automatically, with the volume set at the same level that it was
when turned off, and emit the series of short beeps. Only a few microamperes of current are required to keep the
clock running when the KX3 is off. This is supplied by either the external power supply or the internal batteries.
2
Charging Batteries
For best results, use a set of cells of the same manufacture, age and mAH rating. Most cells will show some
charge even when new but they will have different levels of charge. It is normal to require several
charge/discharge cycles to balance the charges of all the cells making up the battery and give the best
performance.
WARNING!
To avoid injury to yourself or to the KX3:
Install only NiMH batteries rated for 1900 mAH or greater. Do not attempt to charge
any other type of battery.
Check the plastic coating on each cell for damage. The coating prevents shorts between
cells and the shield on the KXBC3 module or other metallic objects.
Do not install or change batteries with external power applied.
To start a charging cycle:
1. Connect the KX3 to an external power source and turn it on (hold the
simultaneously).
2. Hold MENU to enter the menu and turn the OFS/VFO B knob to select BAT CHG.
3. Turn the
VFO A knob to select CHG 4 Hr, 12 Hr or 16 Hr to set the charging time (see calculating
charging time below for help choosing the correct charging time).
4. Tap
DISP
to exit the menu and start the charging cycle.
BAND- and ATU TUNE switches
When charging is in progress, an asterisk ( ) will appear after BT when checking the battery voltage on the
VFO B display. (Tap
DISP and turn the OFS/VFO B knob to select BT.)
To stop a charging cycle:
1. Hold MENU to enter the menu and turn the OFS/VFO B knob to select BAT CHG.
2. Turn the
VFO A knob to select CHG OFF.
Power-Off Pending Mode
If you turn the KX3 off while charging is in progress, the KX3 switches to a Power-Off Pending Mode in which
the charger keeps operating and the charging cycle count-down timer is shown on the display although the KX3
is otherwise off. When the charging cycle is completed, the KX3 switches off entirely.
To exit the Power-Off Pending Mode, hold the BAND- and ATU TUNE switches to turn the KX3 on again,
enter the
BAT CHG menu and set the entry to CHG OFF.
Determining the Charging Time
NiMH cells are reasonably tolerant of over-charging. However, their life and capacity will be shortened by
routinely charging already fully charged or nearly full charged batteries.
NiMH cells have a fairly large self-discharge rate. Typically they will lose about 2% of their charge each day.
There are some types of NiMH cells available that have a lower self-discharge rate, but they typically have less
total capacity.
3
The KXBC3 charges at 200 mA throughout the charging time set, suggesting that 2000 mAH cells would be
charged in 10 hours (referred in battery literature as a C/10 rate). However, the charging process is not 100%
efficient, so additional charging time must be added, typically 20%. So a fully depleted 2000 mAH battery
would require about 12 hours to reach full capacity.
The charging time must be adjusted for batteries of different capacity as follows:
Charging Time (hours) = 1.2 X (cell mAH rating) / 200
For example, to charge fully depleted 2500 mAH cells: 1.2 X 2500 / 200 = 15 hours (Set charger for 16 hours)
Protective Circuits
In addition to monitoring the requested charging time, the charging system monitors the battery temperature,
battery voltage and the power supply voltage. An error message will appear when you are in the
menu or when the battery is charging in Power-Off Pending Mode (pg 3) if any of the following conditions
exist:
Error Message Description
BAT CHG
NOT 0-40C
Battery temperature too high or too low. If this occurs when trying to start a charging cycle,
tap any switch to clear the message. If this occurs during a charging cycle, the charging
cycle will resume automatically when the condition is corrected.
LO SPPLY
The external power supply voltage is too low for charging the internal battery. If this occurs
when trying to start a charging cycle, tap any switch to clear the message. If this occurs
during a charging cycle, the charging cycle will resume automatically when the condition is
corrected.
BAT ERR
Battery missing or battery voltage out of range due to a fully charged pack or a defective or
missing cell. With the KX3 on, tap any switch to clear the message. The charging cycle is
terminated (does not restart automatically when the condition is corrected).
SYS FLT
KXBC3 system fault. With the KX3 on, tap any switch to clear the message. The charging
cycle is terminated (does not restart automatically when the condition is corrected).
Changing Battery Types
If you wish to replace the NiMH batteries with a different type, first turn the charger off;
1. Hold MENU to enter the menu and turn the OFS/VFO B knob to select BAT CHG.
2. Turn the
Leave the charger off until such time as you replace the battery with NiMH cells.
VFO A knob to select CHG OFF.
4
Loading...