I just got my minitor V and charger and it has been charging for a while, and the pager light is green. so i took it out, pressed the reset button, and the battery life on the pager is also full. put when I put it back into the charger a few seconds later, it takes about 5 minutes for the pager to turn from red to green again. Why is it taking so long to get back to fully charged again even though I only took it out for a few seconds?