How can you power superbright LED from a battery efficiently

"linnix"

Just buy a 12V LED flood light, they are well matched at the factory. LEDs are still lower power than CFL.

** But with narrower viewing angles and poor colour quality - ie way too much blue and almost no red.

OTOH, 20 watt CFL delivers about *1400lm* of high quality, white light.

Also, most cameras have a setting for using "fluorescent" light sources that makes the colour look near perfect.

CLFs are cheap to - about $12 for a 12volt, 20 watt one.

..... Phil