I need to power 3 or 6 Super-bright LEDs on a robot I'm building. The robot has a rechargeable 7.2v Ni-cd battery which currently powers the on-board processor and some motors. I plan to tap off the battery, but 7.2v is obviously too high.
I saw the LED array calculator at http://led.linear1.org/led.wiz
which uses resistors and that certainly helps, but would it be better to use a voltage regulator? If so, why, which and how? I'm pretty sure the LEDs are rated at 3.3v and 20ma.