they tend to cost a bit more, but the Luxeon LED's
http://www.superbrightleds.com/cgi-b...gi?product=CAR
for cars seem like they would be ideal, extreamly bright, I have one of the flashlight 3 watt LED's (two of them now) in my flashlight, and they are brighter then kripton bulbs in a mag light (new bulb, flashlight, and batteries comparied side by side), I also gave a 19 LED white cluster that was made to fit in the back up light socket to a friend who has a cabin and ran it straight off a car battery with no charger for many many months straight.
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