In 2006, I completed a 2 month, 2000 mile (3200 km) fully loaded bike tour of Italy.I had a solar backpack to charge my phone and batteries for lights.When I passed through Cinque Terre, I noticed these solar panels on the roof of a train station and had an idea.
When I returned to California, I started researching solar vehicles and found a lot of this.And a little bit of this.So I started sketching out ideas.I got a tadpole trike and started experimenting to get an idea of what was practical.
My first attempt at building a custom solar panel was instructive but the cells all cracked during the lamination process and the panel output was too low to be usable.
It looked kind of cool, though.I found some off-spec satellite-grade dual junction gallium arsenide cells on eBay. The seller was in Mountain View, California so I like to think these were leftovers from a NASA project.In 2008, I got my first taste of success with this 50 watt panel.I upgraded the bike to this 2-wheeled model with suspension and higher seat height for commuting 20 miles a day in traffic. The tail-box fairing was a bit awkward.Later, I experimented with a curved front fairing design using a commercially made semi-flexible panel.After a dozen or so overnight camping trips, I knew I needed more solar to get the daily range I was looking for. I didn’t want the high center of gravity and cross wind issues an overhead solar panel would bring so I started experimenting with a trailer solution.Thanks to an extra battery and a manually operated panel tilt mount, I set a personal single day distance record of 144 miles (232 km) by traveling from Oakland to Pinnacles National Park.I set out to improve on the trailer design by making a one-wheeled trailer from scratch. This first attempt used undersized aluminum tubing and connected to the rear bike rack, causing it to flex like a wet noodle while riding. Not good.A larger diameter tube with carbon fiber reinforcement fixed the flexing problem. An elastomer suspension smoothed out the rough spots without adding too much weight. And a linear actuator added motorized tilting while riding to get more energy.A few more tweaks and she’ll be ready for the ultimate test ride.
Thanks for all of the information, I am thinking of making a one wheel trailer like yours, would you mind me asking what kind of panel you are using these days? Are you still making your own or do you use something from SunPower? Thanks!
Steve
Hi Steve. I’m still running with the same custom panels. One failed and I replaced it with a modified SunPower panel. Details and photos in the blog entry below.
Any semi-flexible panel made with SunPower cells should be fine. The 170W model made by SunPower uses high quality cells. You’ll want two of them if you’re planning on touring with it.
Thanks for that Mark, it seems that in Europe i can only find the 100W sunpower panels, but i suspect some of the other brands probably offer similar performance. I will do some investigations. Are you still touring at the moment? Any plans to if not?
I have a 1 year old child at the moment, so any touring will have to take him into account and my partner wouldn’t want to be left behind so any touring machine will need to seat three… So i think for the time being I am just going to make up some kind of trailer to try things out. Then when I am a little less busy I will think about the tandem recumbent with passenger seat (so much space for panels!)
Hi Mark, can you speak to what model recumbent bike you got and how you feel about it? Any issues you’d suggest looking out for for anyone who’d like to build a similar bike?
Hi Matt. I picked the HP Velotechnik Grasshopper fx for my touring setup. They’ve been making it for over 20 years so it seemed like a proven design. Using the same 20″ wheel size for front and rear wheels as well as the trailer meant that I only needed to carry one size of inner tubes and spare tires on long, remote stretches. Overall, it held up very well to the abuse I put it through over 30,000+ miles. I was generally able to find fixes for components that wore out.
If I was starting from scratch today, I don’t know if I would pick the same bike. The 20″ tires with 2″ max width limit off-road travel to relatively smooth hard-packed surfaces. Packing the bike for air travel requires an extra-large bike box and a serious amount of disassembly and re-assembly, not to mention stress and added transport costs compared to a traditional upright, non-electric bike.
If this is to be your first recumbent, I strongly recommend finding the closest dealer who can arrange some test rides. Recumbents come in a much wider range of styles and configurations than upright bikes and you won’t know what you love and what you might hate until you test ride it.
SOLAR ebike 
Fantastic! Also in Oakland, on a Grasshopper, would be keen to check out one of your prototypes while you’re on your trip, if you are amicable to it.
Cheers, have an incredible journey!
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fabulous, keep up the ingenuity.
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hi, i am working on a e-powered trailer, with solar panel for charging. thx for sharing the info, it is usable.
have fun,
aum
s love nia
eu
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thanks for all the test and blogs, sir
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Thanks for all of the information, I am thinking of making a one wheel trailer like yours, would you mind me asking what kind of panel you are using these days? Are you still making your own or do you use something from SunPower? Thanks!
Steve
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Hi Steve. I’m still running with the same custom panels. One failed and I replaced it with a modified SunPower panel. Details and photos in the blog entry below.
Any semi-flexible panel made with SunPower cells should be fine. The 170W model made by SunPower uses high quality cells. You’ll want two of them if you’re planning on touring with it.
LikeLike
Thanks for that Mark, it seems that in Europe i can only find the 100W sunpower panels, but i suspect some of the other brands probably offer similar performance. I will do some investigations. Are you still touring at the moment? Any plans to if not?
I have a 1 year old child at the moment, so any touring will have to take him into account and my partner wouldn’t want to be left behind so any touring machine will need to seat three… So i think for the time being I am just going to make up some kind of trailer to try things out. Then when I am a little less busy I will think about the tandem recumbent with passenger seat (so much space for panels!)
Thanks!
Steve
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Hi Mark, can you speak to what model recumbent bike you got and how you feel about it? Any issues you’d suggest looking out for for anyone who’d like to build a similar bike?
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Hi Matt. I picked the HP Velotechnik Grasshopper fx for my touring setup. They’ve been making it for over 20 years so it seemed like a proven design. Using the same 20″ wheel size for front and rear wheels as well as the trailer meant that I only needed to carry one size of inner tubes and spare tires on long, remote stretches. Overall, it held up very well to the abuse I put it through over 30,000+ miles. I was generally able to find fixes for components that wore out.
If I was starting from scratch today, I don’t know if I would pick the same bike. The 20″ tires with 2″ max width limit off-road travel to relatively smooth hard-packed surfaces. Packing the bike for air travel requires an extra-large bike box and a serious amount of disassembly and re-assembly, not to mention stress and added transport costs compared to a traditional upright, non-electric bike.
If this is to be your first recumbent, I strongly recommend finding the closest dealer who can arrange some test rides. Recumbents come in a much wider range of styles and configurations than upright bikes and you won’t know what you love and what you might hate until you test ride it.
LikeLike