>Mike:>
>Just curious, are you using any type of voltage cut off circuit
between the battery and KX1?
>
>I use lithiums in my R/C planes and I set my speed controls for a cut
off voltage of 3.0v per cell. I am not a lithium >expert but if the
batteries are discharged too low they will not take a charge.
Mike,
The "Bat Lo" function in the KX1's menu can be set for a value so that
that does not happen. Paul W0RW posted the following to the list a few days
ago:
___________________________
" i wanted more power for /pm operation so i built a LiIon battery
pack with
4 Sony 18650's (1.5 AH) cells to give me 16.7 V, (do this at your own
risk).
Then i use 2 diodes and SPDT (center off) switch to drop the voltage
down to
14V (which is the maximum rating for the KX1) and this gives full
output on
transmit. The voltage goes up to 15V on receive but there is
apparently no
damage. i switch the diodes out of the circuit as the battery voltage
and my
power
output drops.
The 'Bat LO' feature on the KX1 can be used to detect the external
battery
dropping below 13.0 volts by setting the 'Bat LO' to 13.0V. When the
external
battery drops below 13.0 volts 'Bat LO' will be displayed on the LED
and the
battery can be switched back up to 14 volts. The 'Bat LO' is
displayed every
5 minutes and when the KX1 is switched on. So i am using the battery
low
feature to keep the battery voltage above 13 volts. It also tells me
that my
internal NiCads are fully charged at turn on."
______________________________
FWIW, I participated in the NAQCC's 40/80m Sprint last night with my
KX1 (at 3.5 watts) powered by a 3-cell, 450mAh LiPoly battery for about an
hour and 15 minutes. The key-down voltage went from 12.3V at the beginning
of the contest to 11.6V key-down after 75 minutes. I was either engaged in a
contest exchange or calling CQ practically the whole time. Power output
never dropped from my initial 3.5 watts. All this from a battery that weighs
37 grams (1.3 oz).
John Harper AE5X
Portable QRP:
http://www.ae5x.com_______________________________________________
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