remember this small led lights?
supposed to be 9w (3 led) and 12w (4 led), epistar chip.


actual measurements.
9w:

12w:

which makes the efficiency of the 9w at 42.5% and the 12w efficiency at 46.5%
not the led efficacy mind you, but the DC conversion efficiency.

it's freaking low. waste of electricity.
even if the epistar is capable of 100lm/w, the dc conversion efficiency pulled it down. say you get 300 lumen from the 6.56w ac input, the lumen per watt is only 45.73 lm/w.
for the 4 led chip, say you get 400 lumen from 8.64w ac input, the actual output would only be 46.3 lumen/w

lower than even the cheap 11w phillips CFL that i have which is rated for 54 lumen/watt.

install LED to save energy huh?