If I have batteries that are fully charged, but keep them plugged into the chargers while using the spares, does it hurt them to keep them plugged in for more than a day or so?  In other words, is the life of the battery lessened by keeping it plugged in between uses?  Should I be unplugging them once they're fully charged or dosen't it matter?
	
		
			
		
		
	
			
			 
				
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		