Here is a link to a shadowbox dio I built last year.
It has two lightsources. One in the tomb opening in the ceiling (simulating sun) and another one is a search light on the floor. That one was a srtand of a fiberoptic wire. The whole unit was powered by two AA batterries hidden at the back of the box. Had it running non stop for about 6 hours during the show without any incidents so I guess the whole battery/wire/lightbulbs hook-up works.
Unfortunatelly taking a photo without flash gives a very dark result ... with a flash as you all can see looks too bright
Again, it is not pro-level but it may help a bit.