I believe with a DC light powered by a Battery , It Draws, as a resistance load, what it needs from the battery pack ..

Simple Halogen bulb* in Union Headlight reflector , and an on the mudguard 0.6w bulb tail light wired to a 5D cell battery pack of Ni Cads..

In Series, got me home on hour ride for many months...
*It did nor seem to matter what it was rated at , as I Recall , just a Halogen flashlight bulb from Radio shack..

When I had a Schmidt e6 dynamo powered halogen headlight, that bulb selection had to be 3w on its own or 2.4w W an 0.6w tail light...




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