[Elecraft] NiHg batteries How do I test?

[Jim GM]

I have 8 NiHg batteries and charged them for 16 hours.  Charge lasts 5
minutes before KX3 goes dead. Minimum voltage is set for 8.4V. with a 13.6
volts 50 amp DX Astron supply max charge voltage get up to 10.6 VDC says my
KX3. When checking the voltage independantly on each cell they all give me
the same reading on my battery tester saying they are good so the tester is
full of it.

How do I test these cells for find my bad one or 2?

-- 
Jim K9TF