Coming back bike rider and somewhat experienced electrician. In terms of electrical, I've done a small amount of circuit soldering, worked some on automobile electrical lighting and wiring.
I would love to have one of these UPS rounded headlights. Mounted on a bike, I imagine this would be very visible. On the back of the bike, add one but in a red color. Assuming the back has a Hi/Lo setting, run it on low. And then, attach the back light to the brakes, so that when either brake lever is tapped it will put the back light on Hi.
I'm guessing this is probably a 50- to 100-watt light bulb, mounted inside of a glass housing (dispersing the light) with reflector (?) around the bulb. I'm not thinking so much of a light to see in the darkness (although these lights look sufficient) but as a light in the daylight that will stand out from 50-yards away, or quickly catch attention in a rear-view mirror (while avoiding going so far as to blind the viewer).
UPS rounded headlights
How about one of these: Sylvania 14818 25-Watt Incandescent R14 Mini-Reflector Light Bulb?
How hard would it be to, on a budget, attach this to a pack of rechargeable LiPo 18650 batteries? Or a power bank like this product: Solar Charger 24000mAh Portable Power Bank, ALLSOLAR External Battery Pack?
In terms of usage time, according to
this website the energy of a single 18650 is 3.7*2200=8140 milliwatt-hours. So two would be about 16 watt-hours. Four would be 32 watt-hours, enough to power the above 25-watt light for about a one-hour ride. I'm actually looking for about two hours worth of riding on a single charge (45 minutes there and 45 minutes back = 1.5 hours). Two hours would be 50 watt-hours for the above 25-watt light. So that would require about eight 18650 to have a comfortable margin (64 watt-hours).
Are there any recommendable drive wheels (e-bike hub motor wheel) for the front tire that provide enough watts to keep the battery charging up along the ride? How difficult would it be to pipe the power from the front motor into the power pack, of which is powering the light? Or better yet, siphon the power off the tire directly to the light and even it out with power from the power pack, sending excess power from the tire to the power pack (whenever excesses might exist).