Inventing continuously-recharging solar bike
 

Here's a simple electric bike design that should be light and not have to have an additional trailer to hold the panels. I want a bike that can recharge itself when I lock it up outside of a store while running errands during the day. To this end, I'm going to weld two 25w (nominal) panels to the rear rack of a class-1 pedelec that has a 250w mid-drive. I will be using a "ming-he" boost charge controller to charge the 48v (nominal) battery off the 12v (nominal) panels.
Thoughts?

Do you know how many watt-hours you use per mile of travel? On my old home made ebike I used between 10 and 15 wh/mile depending on how much I pedaled. So with 50 watts worth of panels if you were somehow magically able to get 100% efficiency that might give you 3 to 5 miles of range per hour. However, you would want the panels on top of the rack to get the most exposure to the sun. I would imagine your charge controller wouldn't be more than 75-80% efficient and I'm guessing your batteries are lithium which have about a 90% efficiency round trip. So, if you were able to get the full 50 watts out of the panels, then 50 x .75 x.9 =about 34 whrs/hour of charge. That is on the high side because it will be rare that you'd get the full 50 watts from the panels. So maybe an extra 2 to 3 miles of range for an hour of charging. Would also have to consider the additional aero drag from the two panels at anything above fifteen mph so that might cost another 15% efficiency. All that said, it looks like a fun project and I'd like to see your before and after results. Also on days when you are not riding much you get free energy from the sun. JJ

This scooter owner took a page from satellites (retractable folding solar array). Orienting it to the sun helps immensely, if it's a practical option to move your bike periodically.


https://ecorenovator.org/forum/attac...1&d=1584033516


Above rig is suitable for 5 mile / 8 km daily usage.



Downside: windy days!


https://www.builditsolar.com/Projects/PV/pvscooter.htm