I go to the local flea market often and this summer one guy had these up and running from a small 12-volt lead-acid battery. I think some 30 x 2 rows (~60 leds). Quick calc; say some 4 amps each emitter for some decent illumination at 6 volts each = 120 amps draw. No go on this small battery. Housing seemed Ok (cast aluminium) but doubt there was any regulation in that. Although was in broad daylight, and the leds were bright (screaming white – but people go for that), didn’t throw any light into the adjacent tent.
Came back a second time some 2 weeks later, don’t think he fished enough.
Also saw some fellow selling those 2 for $10 zoomies with incredulous ratings. He would come again some 2 or 3 times. That was last year, doubt he’d show up after doing his gig and people realizing being duped.
Travelling salesmen – snake oil.