Hi, can anyone help me? I want to run a 12v led bulb as a cycle helmet light as i am a keen mountain biker. i am trying to rig a 12v led bulb to my makita 18v battery as i have a lot of these batteries being a carpenter. i currently use a 12 halogen bulb which works really well but drains the battery after 30 mins and gets so hot it is starting to melt my helmet. i have been using this setup for about a year and is amazed the bulb still works. i tried to use a 12v led bulb and it was everso bright but blew after about 20 seconds. can i use a resistor or a 18v to 12 converter that wont loose any of my battery compacity. any suggestions would be much appreaciated....