charging output for lights

[JEFF400EX]

I need to get a cheap set of lights for my 400ex, cause I put new race cut fenders on.

Do you guys know what the wattage is of the charging system?

I will end up getting cheaper ones from an auto store or walmart, but I'm unsure as to the out put watts or recharging size issues to watch for.

I would like to get the smaller round ones to mount to the handle bars.

Any ideas or help to get me in the right direction, I would be very greatful.

Thanks
Jeff