[Elecraft] KX3 internal battery problems

[Bill Frantz]

Another thing to check is corrosion resistance at the battery 
contacts. I find this problem frequently with flash LED 
head-mounted lights.

When I have a problem like this, I like to measure the cell 
voltages under load. You may be able to run the KX3 into a dummy 
load at the 0,1W tune setting and measure each cell. If one cell 
shows significantly lower voltage, it is the problem. Running 
this test again several days after the battery was last charged 
will show cells which have high internal self-discharge.

73 Bill AE6JV

On 5/6/16 at 3:06 AM, ptaa at ieee.org (LA7NO) wrote:

>KX3 (ser. no. 08146) works OK on external power, but recently I am
>experiencing problem using it on internal rechargeable cells.
>
>The AA cells are relatively new Varta Professional No. 5706, 2700 mAh NiMH.
>They have been charged with a techno-line BC-1000. Measured capacity via an
>automatic discharge/recharge cycle is according to spec.
>
>I have attached a 50 Ohm dummy-load to the KX3. When turned on, it indicates
>BT 9,7V.  BAT MIN is set to 8,2V.
>When I press ATU TUNE, it turn itself off immediately.
>With TUN PWR set to 0,1W it works OK when pressing TUNE, but BT drops to
>7,6V.
>If TUN PWR is set to 1W, it switches off when TUNE is pressed.
>
>Strange that the voltage drops so much, even if the charger indicated normal
>cell capacity when automatically discharging them.

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