The Makita DC18RD Twin Port Charger is able to charge two Makita slide style Li-ion and Ni-MH batteries (with adapter) at the same time, this is as fast as the DC18RC charges one battery.
The DC18RD has full charge sound alert, an LED charging display, and electronic current limiter which provides overload protection.

The Twin Port charge times are: 2 x 18 Volt 3.0ah Batteries: 22 mins, 2 x 18 Volt 4.0ah Batteries: 36 mins, and 2 x 18 Volt 5.0ah Batteries: 45 mins.