Redesign of my original led light bar mount for the Prusa MK2S: https://www.thingiverse.com/thing:2823709, now for the Creality Ender 3.

I found the mount for the MK2S to work so well that I modified it slightly to work on my new Ender 3. All you need to mount are 2 x M4 screws and 2 x T-Nuts. If you want it a little more rigid you can add 2 more screws and T-Nuts and use the rear holes, although I have not found it to be necessary. This mount does not interfere with the movement of the printer or filament in any way. The light bar is angled at ~30* which seems to distribute the light evenly over the print surface.

I used orange PETG with 4 perimeters and 40% infill for strength, but 2 perimeters and 20-30% would probably suffice. There is no difference between right and left so just print 2 to mount a simple LED light bar.

I had a few questions regarding my light bar...I made it myself using aluminum led mounting hardware, 4 x 3W LEDs, and a constant current buck converter:

Aluminum Channel: https://www.banggood.com/50CM-Aluminum-Channel-Holder-For-LED-Strip-Light-Bar-Under-Cabinet-Lamp-p-1199458.html?ID=522225523067

LEDs: https://www.amazon.com/gp/product/B01DBZICDC

CC DC Buck Converter: https://www.banggood.com/LED-Driver-Charging-Constant-Current-Voltage-Step-Down-Buck-Module-p-939196.html?cur_warehouse=USA

Since the Ender 3 power supply is 24V I was able to hook all 4 LEDs in series and buck the voltage down to 12-13V. I found that when I set the buck conv output voltage to 13.6V and the current limit (CC) to ~500mA the light would flicker at times, so I backed down the voltage until the CC led on the converter went out and the flickering stopped. Its not a good idea not to run the LEDs at or even close to the maximum anyway as they will get crazy hot.

I used small strips of perf (PCB) board cut to slide into the channel and soldered the LEDs/wires to them, making sure to insulate it with kapton tape to prevent shorts.