I'm working on a project for my engineering class, we have to make a R/C boat. I'm useing a dc car heater motor and to power it I'm useing batterys made up of 3 NiMH 1.2V 1700mAh cells. I'm wondering what's the best way to charge these batterys? I have dc transformers rangeing from 4V/.8A to 4V/.15A to 15V/1A and a bunch inbetween w/ varying voltage and amperage outputs. (I use a multimeter so I know exactly what each battery and transformer is doing)
so is there a rule of thumb for how many volts/amps you should put into the battery?
like what would be the ideal way to charge a 3.6v/1700mAh battery? what about for two of those batterys wired parallel?

any help, or links to information, would be much appreciated.
thanks