The batteries are most likely not at the end of their life.

There are a few things that you can do.

1. Check the battery type on your LX9000, is it set to LiFe?
2. Check the voltage reported by the LX9000 and compare it to the voltage reported by another instrument. Most radios have a voltage readout and often this is more accurate than the 9000 readout. IF they are different use hte voltage offset function in the 9000 to have it read the same voltage as the radio.
3. If 1 and 2 don't help, put the K2 batteries on an extended 10 day charge cycle. This helps balance the cells and restore capacity in the K2's.
4. If this doesn't work, put them on a longer 20-30 day charge cycle.

The K2 batteries should never be stored for a long duration at full charge. Always store them at about 1/2 charge and then when they come out of storage put them on a 10 day float charge. Do this once a year.