Depends upon the size of the batteries in the case of NIMH/CA. A gel cell usually is charged overnight. A 3000 ma NIMH can be charged in a half an hour at 4 amps. Marty
If you really want to look into a charger for everything rc most folks will probably ever use, check this out: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXUAB8 I have one and really like it. Also nice to have the AC/DC adapter that comes with the pro version and to not have to buy leads separately for connecting to the batteries...