[Elecraft] Kx3 lithium batteries life

[Kennet4723 at aol.com]

I have had lithium batteries in my KX3 since I received it last Nov.   I 
use the batteries only to keep the clock alive and have never used them to 
transmit or receive.. I use an external power supply to transmit etc,  I now 
find that if I try to turn on the rig using just the batteries the rig comes 
on then immidiately turns itself off.  I assume the batteries are to the 
point where there is not enough voltage to power up the rig but the B T voltage 
reads 10.5 to 11 volts which I thought should be enough to turn the rig on   
Does the clock in the KX3 take that much  power that even lithium batteries 
have a very short life .??  Has anyone else experienced this situation??  
Is there something I am missing ??
 
Ken   K1DWZ