Ranger battery case problem

I have a Ranger RX battery pack. Recently i have started to notice that when i pick up the battery pack while it is on, it immediately switches off. It seems that the battery does not fit as well as it once did so picking it up disconnects the contacts on top of the battery. (this bit will only make sense to someone who has one and has seen the strangely rudimentary connection method)

Anyone else had this problem before?

Did you make sure that the battery is really locked into the case? When you place the case over the battery and set it down, you should hear a click (actually two clicks since there's a lock on each side of the case) when the case is pushed all the way down and locked in place.