I had some great success with this so I thought I'd share! My goal was to create bright, efficient, and more importantly, inexpensive lighting for my sailing dinghy without dropping in a 12V lead acid battery for incandescent bulbs.
Here's what I used (besides tools):
- Attwood 3121 navigation light: goo.gl/05pVw
- Defiant 12 LED flashlight: goo.gl/GvZww
- 3xAA battery pack with switch: goo.gl/F3xuW
- Dorcy LED lantern: goo.gl/Wn2l9
Here's the LED flashlight I started with. Notice the LED pattern.
I cracked open the flashlight, de-soldered the LEDs, and mounted them sidways on their own solder pads. Then, I scraped off some solder mask and "doubled the thickness" of the LED stack. I wrapped two pieces of bare wire around a bottle cap and made ground rails to fit, then soldered them to the board.
The LED driver was mounted to the LED board with a few stacks of double-sided foam tape.
For the light housing, I opened it up and removed all the fuse lamp junk, snipped and sanded the bottom flat, then attached the LED boards to it with a little tower of double-sided foam tape. I mounted it to the boat, drilled a small hole through the inside of the light housing and the boat, then ran the power wire down through it.
The wire soldered to the battery pack and coated with heatshrink, then attached to the boat with more double-sided tape. The switch is accessible, and the batteries are easily replaceable by removing the door from the pack.
For the anchor light, I simply ripped the handle off the Dorcy LED lantern and ran some rope through it. This gets tied to the end of the bow.
Hope this helps inspire you