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Old 02-05-20, 11:47 AM   #2
Helper EcoRenovator
Join Date: Mar 2009
Location: Sacramento,Ca
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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
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