Set it at as low an output as you can, it's best for the battery. Time duration, depends on two things, the output amperage of your charger setting, and the mAh of your battery. So if the lowest output of your charger is 1.7 amps, then it'd take 1 hour to charge that 1700mAh battery. If 1A is the setting, it'd take 1.7hours. 500mA output, 1.7A/0.5A = 3.4 hours.
Pretty easy overall.