Out of curiosity, I tested one of these cheap passive poe cable kits with a Raspbery Pi 2 with different cable length.
The results are rather disappointing, if not surprisingly so.
A 1m cable works fine, and with a quality 10m cable, the leds of the pi won’t show even the slightest flicker.
With a 5m cable, the RPi on its own starts and would probably work fine, but with a FA Orange stick (or a cheap oem stick, for that matter) it does not boot, and when plugged in later, the Pi immediatley shuts down. I tested this with two different power supplies, a 5V 2A and a 5V 3A power supply.
I guess the solution, as stated above, is feeding at a higher voltage and convert it back, which is the same thing these other kits are doing.