A general rule for NiMH: Max charge at 1C (150mA) and max discharge at 10C (1,5A). Most NiMH-batteries handles these currents. Of course there are batteries which handle more current... The long tiny cells are for low current and the short thick ones for high current/motor.
A new NiMH shall be charged at 1/10C for the first time, and also if it is stored for a while. NiMH have to be cykled 4-5 times before they have the full capacity. They also loose capacity quite fast... If stored for 2-3 months they usually require some cykles before they are shipshape again.