Originally Posted by
Redhatter
Sounds like a plan for a back-up but what powers the light when you stop? Last bike I had (rim-mounted) dynamo lights on you had to get about 20km/hr to see anything with them and lacked any sort of battery to keep them lit when you stopped.
No, good lights have a 4-minute diode in them so that they stay illuminated. Also, nowhere near 20km/h is required. Available for much less than $60.
Or, you can go the battery route and blind people, which is asinine. (Note, that last comment isn't directed at you, in particular).