I hate this "feature" and in my quest to try and figure out how to disable it on DIrty Unicorns I discovered something on stock. If you go to sys/class/leds/charging, and change the brightness file from 0->100 It will enable the charging LED on the stock rom.
I suppose you can change this number anywhere from 0-255, but I only tried it with 100.
Root Required to save the change.
