Generating Joy Part 5: My Solar Tandem Project
- Laurence Clarkberg
- 3 days ago
- 8 min read
“For over half a century the automobile has brought death, injury and the most inestimable sorrow and deprivation to millions of people.”
—Ralph Nader, Unsafe at Any Speed
This is Part Five of a five-part series about the Ithaca Generator to accompany the Generating Joy show at the Cherry Gallery from 1/23/26 to 3/8/26.
I began my professional career as a mild-mannered web designer way back in 1996 when creating a web page required first typing "<html/>". By 2010 I was getting tired of sitting at a computer all day. I wanted to do something with my hands instead, something tangible. Then I saw a photo in Make Magazine that changed my life. It was a photo of an electric cargo bike. I realized that in order to keep humanity from destroying planet Earth we all need to build electric cargo bikes to replace our cars. So I taught myself how to repair bicycles and how to weld and I started my own bike shop.
In 2016 I had a sort of spiritual awakening that super-charged my creativity. My friend Doug Shire (who had had a similar sort of awakening at Burning Man several years earlier) witnessed my change. He harnessed my creativity and welding skills to help him create a series of art bikes that we took to Burning Man and many other festivals and parades (see Art Bikes and Beyond at Ithaca Generator).
In 2022 I saw this video that shows how easy and inexpensive it is now to power an ebike with a small solar panel. I realized that a solar-powered electric cargo bike could really save the world. And so I temporarily turned my attention away from art bikes and back again toward practical transportation. By that time I had divorced and re-married and my new wife Judy has been very supportive of my wacky bicycle creations. So I decided to explore how to add solar panels to a tandem ebike that we could ride together. I've spent the last three years developing several designs that Judy and I have tested on lengthy bike tours. My three designs were to add solar panels to a tandem delta trike, an inline tandem and a recumbent tadpole trike. Here is a summary of the results with lots of links to my previous blog posts, and ending with a juicy hint at my solar-powered project for this year.
Why Build a Solar Tandem?
Firstly, what is motivating me to spend thousands of dollars and hundreds of hours building a solar-powered tandem? Can't we solve the climate crisis by replacing our gasoline-powered cars with EVs? As I wrote in an earlier blog post, no. EVs aren't the answer. "EVs, as the car manufacturers are currently conceiving of them, only solve one class of problems with our current transportation paradigm, the problems associated with using a toxic substance for fuel. Mainstream EVs all continue the stupid paradigm of unnecessarily fast, heavy and wide vehicles. They all continue the paradigm of forcing you to drag around three unoccupied seats (and sometimes an unfilled truck bed) wherever you go. As bicyclists, Judy and I are used to challenging the assumptions of car owners. One assumption is that you need to carry around a heavy steel and glass enclosed space wherever you go to protect you from the elements. Bicyclists achieve the same transportation functionality simply by dressing for the weather. Another assumption is that you need a vehicle capable of speeds over 30 mph that can go distances of over 300 miles. This may be true for travel between cities, but most people most of the time travel at less than 30 mph for less than 30 miles a day within their own city. A typical car is designed for long-distance travel at high speeds but is actually mainly used for short-distance travel at low speeds. The tool does not match the job. Current car use is like using a sledge hammer to hammer in nails. This is shameful and will lead to disaster." Read more rhetoric like this in my blog post "Designing the Sun Lover Part 1: Why Cars Are Stupid".
The solution is to build a lightweight narrow solar-powered vehicle. My design criteria for a “bicycle that can replace a car” are:
Top speed of 30 mph
Range of at least 60 miles
Able to carry enough solar panels to recharge from four hours of sunlight or less
Weighs less than 200 pounds
Able to fit through a standard door, so less than 30 inches wide and 78 inches tall
Less than eight feet long
Costs less than $5,000
Able to carry two people and 100 pounds of their groceries or gear
Performs well on trails as well as asphalt
And as you will read below, meeting these design criteria is totally doable, even by a wacky bicycle mechanic working out of his garage.
The State-of-the-Art
Secondly, what is the state-of-the-art of solar-powered vehicles in general? In a previous blog post (Here Comes the Sun Pony) I covered the sad history of solar cars, how in 1987 none other than General Motors did create a solar-powered car, the Sunraycer, that won the World Solar Challenge, a week-long race across Australia. GM used the technology they developed to create the first production model EV, the EV1, in 1996. But, fearing that EVs would compete too well against their gasoline-powered cars, they killed the project. Other people have continued to develop solar-powered cars, especially university students in the context of the biennial race across Australia now called the Bridgestone World Solar Challenge. See, for example, this exciting video about the 2025 race.
However these solar-powered cars cost millions of dollars and are not very practical. A better approach is instead of downsizing cars so that they are lightweight enough to be solar powered, we should be upsizing bicycles so that they can be solar powered. This is the approach taken by the racers in the annual Sun Trip. For this race 30 to 50 bicyclists have created homemade solar-powered vehicles that they take on an extended tour using only pedal power augmented with solar power. In 2018 the racers travelled 7,000 miles from Lyons France to Canton China as shown in this exciting video. Judy and I dream of someday racing one of our creations in the Sun Trip.
The Sun Pony (2023)
My first design was to mount solar panels on a Worksman tandem trike. We called it the Sun Pony. The Sun Pony is a delta trike with two side-by-side seats. Two sets of pedals in front of the two seats drive each of the rear wheels. Judy and I live on a long steep hill in Ithaca NY and so to make the Sun Pony practical I added three motors: two crank drive motors to the cranks and a hub motor to the front wheel. The Sun Pony worked well for short slow trips. It would be a great vehicle for towing a trailer full of compost around on a farm, for example. But it was not optimal for long cross-country touring. One unexpected issue is that many New York State country roads now have "rumble strips" on their shoulders which makes it very difficult to ride the 40" wide Sun Pony on the shoulder. And much bicycling infrastructure is too narrow for the Sun Pony to pass through, including some gates on rail trails. Lastly, because lightweight tricycles are in danger of tipping over when turning at speeds above 20 mph, the Sun Pony had limited usefulness in city traffic where vehicles are expected to travel at 30 mph.
The Sun Lover (2024)
The next year I created a second design which was to add motors and solar panels to an inline tandem. We called it the Sun Lover. I began by adding a rear hub motor to the bike but Judy and I discovered that on steep hills the motor was in danger of overheating. So I added a second motor, a BBSHD crank drive, to the rear crank. It was an engineering challenge to add both a crank drive motor and a hub motor to this bike, and to design an overhead solar panel. See how I solved these issues in my blog post "Designing the Sun Lover Part 2: Build Story".
Some of my friends were concerned about the safety of the Sun Lover so I addressed their safety issues in my blog post "Designing the Sun Lover Part 3: Why Bikes Are Safer Than Cars".
The Sun Lover is exceptionally fast, easily accelerating up to 35mph on level ground within a few seconds. And it is built to carry a lot of weight. And it is as narrow as a regular bicycle, making it easy to navigate bicycle infrastructure. However, Judy and I discovered that the coordination required to balance a bicycle with two people on it was very tiring. We didn't like using this bike for long tours, although I continue to use this bike solo to run errends around town.
The Honeycycle (2025)
My third design was to add solar panels to a Terra Trike Tandem Pro, a very classy recumbent tadpole trike. Again I added both a BBSHD crank drive with low gearing for hill-climbing and a beefy Grin All-Axle hub motor for its regenerative braking and for cruising on level ground. It was pretty easy to add 400 watts of solar panels to an overhead steel structure. I plan to write a full build description of the Honeycycle at some point but in the meantime here is a short video that Judy made: "Meet the Honeycycle!"
As a recumbent, the Honeycycle's riding position is very relaxing and so it's easy to go long distances. 100 miles in a day is no problem. Riding it is like sitting in a low lawn chair while moving your feet in a circle. And being low down, the wind resistance is very low. The center of gravity is also very low making it pretty stable although not as stable as a bike with two inline wheels. (For a great explanation I wrote about why this is so, see "Designing the Sun Lover Part 3: Why Bikes Are Safer Than Cars". So even though the Honeycycle is capable of higher speeds, I keep it below 25mph.
The Honeycycle has proved to be a great design and I can imagine someone coming out with a production model some day soon. Last summer Judy and I rode the Honeycycle in the RAGBRAI, the world's largest organized bike tour. We rode about 400 miles from the west end of Iowa to the east end over the course of a week while camping out along the way. As many as 20,000 other bicyclists rode with us. It was an epic journey! Here are the blog posts we wrote about it:
The Future: Solar Boats
This summer I plan to apply the same solar technology I brought to tandem bikes to small boats. For starters I plan to add motors and solar panels to some kayaks we have behind our garage. See this overview of solar-powered boats that I wrote recently: "Let’s Make Some Lightweight Solar Powered Boats!" And check back on my progress in a few months.
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