Was it functioning correctly when you first got it??
Not sure about Magellan units, but the battery cannot be removed in many, for example, a Garmin. They can be charged by a separate charger by plugging into a 120V wall outlet or from the car (12V) or a computer but the computer USB connection (5V) is very slow charging if it charges at all (at least in my Garmins). With mine, I have to double check each time I turn it off to be sure it is, otherwise the battery runs down quite quickly even though the screen is blank. (I have never tried to remove the batteries in either of mine so I don't know if the battery portion is removable as a unit and replaceable or not. The Garmin reference material says NO).
Googling "charge magellan roadmate" reveals many different articles on the subject: Most seem to say you should charge it from the 12V adapter from the car. You can find the manual here if you don't have one:
http://support.magellangps.com/support/index.php?_m=downloads&_a=viewdownload&downloaditemid=461&nav=0,388,415
It will take approximately 4 - 6 hours to fully charge the battery using the supplied vehicle power adapter. You may also charge your device using a USB cable however the rate of charge will take much longer than 4 - 6 hours. When charging the device battery using a USB cable power the unit off.
