Good battery choice to power LEDs an Iron Man arc

Not sure if this is the right place, because this is one of my first non-arduino powered projects. What would you say is a good battery choice to power LEDs an Iron Man arc reactor?

I'm making an arc reactor from Iron Man for Halloween. I thought about initially just running the wire that provides the power to some sort of battery that would be in my pocket.

But I thought it'd be cooler (and neater) if I could find some sort of battery to stick on the back of the prop. Do you think there's a battery, rechargeable or not, that could fit on the back of the reactor, and still provide a good few hours of constant LED lighting? How would you do it if you were me?

I'm new to portable battery powered devices :stuck_out_tongue:

Thanks! Looking forward to completing it before Halloween.

RC lipos should do the trick, you will need a special charger, but they have the best energy density of any battery.*

*(unless you can get hold of military batteries, before anyone corrects me)

CR2032 run throwies for hours, use one CR2032 per LED and you should be good.