MR 11 and MR16 bulbs are built to run on AC or DC.They have a rectifier built in the back.The good MR led bulbs have a muffin fan inside them!There are 2 types of MR bulbs,low voltage and high voltage,both run on AC or DC,and both have a huge range of voltages they will run on.

You can hook them up directly to your hub.3 leds work best,2-1 watt in front and 1 in back or 1-3 watt in front and a battery blinky in back.Hub dynos work best at 3 watts,that's what they are built for.

You can daisy chain 6,7,8 together if you want but your going to be riding at a good pace to keep them all lit up.

They are NOT the most efficient way to have leds but it's one of the easiest.I like them,I can buy a bulb anywhere if need be.

I run a cree 3 watt MR16 in front and wired a Planet bike 5 led blinky in back.I thought the Planet Bike blinky would burn up but it's hanging in there good so far.They do blink at walking speed but above about 3MPH you don't see it.Actually they blink all the time on AC,it just blinks too fast.