Tokyo Marui Battery Trickle Charger (Mini Tamiya)
This Tokyo Marui made charge has been specifically built for 8.4v 1300mah batteries. It features a time-out function that activates an LED on the charger housing after 4 hours and 20 minutes has elapsed. However the charger can be used for other varying capacity batteries. Just be sure to keep a careful watch on the battery and makes sure it does not overcharge. The output is 300mah, so if your battery 1800 mah it will take approximately 6 hours to charge the battery from a flat state.
*Note: NiCd batteries must be discharged or completely drained before charging to prevent the battery from recrystallizing and developing a "memory". If your NiCd battery develops a memory you will notice that over time the battery will seem to hold less and less of a charge.