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Old 04-18-2009, 10:30 PM
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Earthman Earthman is offline
Motorized Bicycle Senior Member
Join Date: Mar 2009
Location: Pittsburgh, PA
Posts: 82
Default What wattage headlight to use?

Does anyone have any thoughts on what minimum wattage bulb would be appropriate to allow reasonable safety on a motorized bicycle while going 20 MPH on a dark street?

Iím building a 12v electrical system for my motorized bicycle and Iím trying to figure out what size bulb (in Watts) to use for the headlight. This seems to be the hardest part to work out Ďcause thereís lots of trade offs with respect to brightness, weight of battery, life of battery, the reflector used, etc.

I'll probably end up building the headlight since I haven't found anything commercially made that will meet my needs. Iíve got most other things figured out. For example, I want to use a 2 A-hr gel cell battery max to save weight. I only need about an hour of ride time, which puts me in the 10 to 20 Watt range for the bulb, but I have no idea what can I get away with.

I'd appreciate hearing from anyone who has been down this road before.

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