Yes Camcorder manufacturers are a little bit naughty when it comes to quoting battery life, the figure quoted is what you would get if you switched the camera to record and did not touch it again, - no stopping - no starting, no zooming (in or out) - no LCD screen - just straight record.
But as soon as you start zooming, starting and stopping or using the LCD screen battery life drops dramatically - depending on what you were doing then 20 - 30 minutes could be quite normal - especially if it was also a little cold - this is about what I get if doing a lot of zooming, pausing and restarting.
Spare batteries are essential - especially if you are going on holiday - although your battery may be designed to be charged on the camera there are third party manufacturers who sell battery chargers for charging the battery when not on the camera - have a look at
http://www.keene.co.uk