Nuker, don't raise it part way, raise it all the way. Anytime you run your transmitter with the antenna NOT fully extended, the SWR (standing wave ratio) goes way up and causes excessive heating of the output stage. Anytime you are running with collapsed antenna, you are accelerating the failure rate.
It is never a good idea to discharge the transmitter by leaving it on as you also risk damaging the weaker cells. Should one cell go flat while the others still have some charge, you reverse charge the weak cell further damaging it, perhaps catastrophically.