Tell us about yourself!
I have used my own version (will publish it later) using a plastic straw through the cap and into the water. I passed the wires from a small 5 V solar panel to a LED at the base of the straw, insulated it (prevent water from getting in) and voila! No need for serious hole in roof (just a small one to pass wires through). Hanging the light from the roof is not to difficult either - the bottle's neck provides sufficient grip. The installation also has a small Power 500 charger for a LIPO battery and a light switch for obvious reasons. More to follow.
I made it! Thanks! I added the green LED for when the temperature is within parameters.