The charger I've been using for a couple months died for no apparent reason.  It runs 48v/4.5Ahr and is widely available.  I happen to get mine here:  
http://www.scooterpart.net/partpage/1812.htmI took it apart to see why it stopped working.  It's fuse blew.  I promptly replaced it with some 18g wire... not an improvement.  Has anybody else had problems with this charger?
There are a few sub-$100 alternatives out there.  Would anybody recommend one?
Thanks!