I put together a very inexpensive planer board indicator light last year that I used for trolling for salmon at night. Consists of LED's that can be purchased from Radio Shack for $3.00 for a bag of 20 in various colors. I use a #2032 lithium battery and a metal spring loaded paper clip to attach the light to the planer board. This setup will last for many hours on one battery and is very easy to install and remove. Total cost is less than $2.00 and would be considerably less than that if you can buy the batteries in bulk. If there is any interest I can provide more details.