There is no way you are going to charge 1600 Mah batteries in one night with a wall-wart charger. Those will charge a 600 Mah battery in one night, but not 1600 Mah. If you want to be able to charge TX and RX batteries overnight you are going to need a new charger.

[link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXL331&P=7[/link]

I have a couple of these around and they do a great job. There are 4 power taps on them with varying capacities, so you can charge different rated batteries.

Ken