Yahoo Autos Three-Wheeled Solar Machine Makes Cross-Country Trip in 13 Days
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The modern vision of a Cannonball Run finish is a high-powered Mercedes-AMG or a BMW M5 screeching around the corner and banging off the rev limiter in an attempt to shave just a few more tenths off its New York-to-California cross-country time as the driver slides the car towards the official finish line at the Portofino Hotel in Redondo Beach. If you watched the movie, maybe it's a Countach or a Dodge ambulance in your head, but whatever you're thinking of, it's probably not a silent-running, three-wheeled solar machine that looks like the offspring of a paper plane and a tricycle.
Well, add it to your mental picture book. On July 21, 2024, Will Jones, Kyle Samluk, Brett Cesar, and Danny Ezzo—four engineering students from Michigan with an EV built out of eight solar panels and three bicycle wheels—set a new record for making the run from Red Ball Garage in New York City to the Portofino Hotel in Redondo Beach—the famed start and finish of the Cannonball Run. If you haven't heard of the Cannonball Run, well, welcome to Car and Driver. We're happy you're here. The Cannonball started in 1971, a stunt by C/D's own Brock Yates, who felt a protest was needed against increasingly strict traffic laws while at the same time celebrating the beauty of the American interstate system. This is what we were like back then. Yates made the first dash in a Dodge van, but subsequently upgraded to Dan Gurney and a Ferrari for the next year's Cannonball Baker Sea-to-Shining-Sea Memorial Trophy Dash. In contemporary times, the run has become bragging rights for folks with questionable on-road ethics, and as a top-speed run, we find ourselves unable to support it. However, the solar car team was not making a top-speed run.
The claimed fastest time between the Red Ball and the Portofino is Arne Toman and Doug Tabbutt's 2020 run of 25 hours and 39 minutes. The Cannonball Sun team (see what they did there?) completed their journey of 3000 miles in 13 days, 15 hours, and 19 minutes. No speed limits broken, but they did beat Joe Kliewer's previous solar attempt of 2800 miles in 58 days. For Jones, Samluk, Cesar, and Ezzo, the goal was to complete the run in their ground-up construction with no charging stations, no diesel generators, and no major breakdowns.
The vehicle, dubbed Sun Strider, is registered in the state of Michigan as a motorcycle. It has tail- and brake lights, and it had headlights until the front nose cone melted in the desert heat and lost its shape, dislodging the lights from their housing. The bicycle tires, well, they aren't exactly DOT approved, but it seems the vehicle inspector let that one slide.
I got a preview of the Sun Strider the day before the intrepid trio finished as they came through the high desert of California. I had the car on the tracker and knew approximately where I would encounter the team, but nothing prepared me for what it looked like on the road. The Sun Strider has a frame made of square steel tubing with eight solar panels flat on top. Any aerodynamic body pieces are fashioned out of corrugated plastic save for curved parts like the front and rear nose cones which were 3-D printed. A small plexiglass cupola serves as the cabin, and three tiny mountain-bike wheels are all that touch the ground. It looks like a satellite and was doing a blistering 35 mph on Highway 62, tailed by a rented Ford Expedition and a trailer full of spare parts.
After a half-hour or so, the team stopped for a driver change. Although they were far ahead of the Tesla record, the team wasted no time in the swap. The solar panels are hinged on one side so they can be propped up allowing access to the cabin. One driver clambered out, accepted a cold bottle of water, and gave his sweaty, disgusting helmet to the next driver. Remember, it's officially a motorcycle, and California is a helmet state. The next driver strapped into a seat that looks like it has all the comfort of the last row in economy on Spirit Airlines, checked comms on the helmet, and 30 seconds later they were on the move again.
Driver swaps varied depending on road conditions and ambient temperatures. When it got really hot in the cabin, they would change every 30 miles or so. I asked about the highest temperature they saw in the cabin and Ezzo proudly said, "128 degrees."
Nutso.
The Sun Strider has a lithium-ion battery pack with a total capacity of 2.9 kWh that the team built themselves, painstakingly welding each of the 320 cells together. They did this so they could package the 38-pound battery to their unique specifications but also so that if something went wrong, they would be familiar with it and easily be able to diagnose problems.
Fortunately, the battery worked flawlessly, maintaining optimal temperatures the entire trip. The motors, however, were a different story. The team purchased motors from a Canadian company specializing in e-bike propulsion. Each is rated for 3.2 horsepower, and the guys put one on each wheel for a three-wheel-drive platform. While their route avoided the Rocky Mountains, they still had plenty of elevation gain along the way, and the motors had a hard time handling the necessary current. A 560-pound vehicle plus a driver puts more load on the equipment than a lightweight e-bike. By the finish, the team had replaced two motors in the rear, and the front motor was barely limping along.
"We had five very functional motors in New York City, and we're down to two and a half somewhat functional motors at the finish," said Jones. "We needed all three to climb the Sierra Nevadas on Angeles Crest Highway. Two motors were rock solid. One of them has been a problem since before we even left New York City, but it finished it out. The other two have been useless. If we did it again, we'd definitely use different motors."
The team also had a bit of a problem with the MPPT solar charge controller. This little box of engineering magic takes the power from the panels and decides if that power should go to the motors or to the battery. The controller took a dump in Desert Center, California, which, as a California desert dweller, I can attest is the worst place in the California desert. There is no restaurant or gas station, no trees, and no shade. The team had to spend two hours in the blistering 115-degree heat diagnosing and fixing the MPPT so they could get on with the business of making solar-powered history.
The schedule was the same throughout the trip. Get up early and flip up the solar panels on the car to take advantage of the low-level light. After two hours, the battery would be 95 percent full and ready for the first driver. Those in the chase vehicle would keep an eye on weather reports, constantly weighing the forecast against the battery's state of charge.
"There was one time when Kyle and I were duking it out," said Jones. "I kept telling him 'We gotta go!' and he said, 'We can't make it!' I told him, 'If we don't make it, we're going to be sleeping on the side of the highway and get bombed by White Sands missile range!"
The team was conservative with the battery, rarely letting it drop below a 40 percent state of charge. If it was sunny, no problem—the motors can take power directly from the panels. But if it clouded over or even rained, that could throw a monkey wrench into the whole darn thing. Still, on most days they cleared well over 200 miles of driving. As added insurance, the team would charge the battery in the late afternoon sun just in case the following morning was clouded over.
I'll admit I was surprised when the team asked me if I wanted to pilot the Sun Strider through the Portofino Hotel's parking lot to the trailer, but I'm not going to turn down a chance to drive a weird thing. I settled in behind the handlebars and fired up the battery, MTTP, and motors. There are traditional pedals for the throttle and the front brake, but the latter hasn't really worked for much of the drive. Instead, I used the two hand brakes on the handlebars to stop.
As I gently cruised through the parking lot, it immediately becomes obvious that piloting this for any amount of time is some serious Type 2 Fun—as in, not fun until later when you brag about having survived it. The cockpit was already uncomfortably hot, the seatback was pitched at such an angle that I had to just sit forward if I wanted any chance of seeing anything out the front, and the wimpy tires and lack of any real suspension mean that any imperfections of the pavement go right to the old behind. It was nerve-wracking to drive at 10 mph. At 35 mph, it must have been terrifying. Going 50 downhill? Better them than me.
I had to navigate a tight turn in the parking lot, and the Sun Strider did not want to comply. Only now do I realize I could have used just one of the rear brakes to pivot, since they each had their own controller, but instead I just slowly inched around the turn, barely missing some orange cones. I brought it to a stop at the trailer and asked Ezzo about their stats for the drive. "This morning after 80 miles of driving we saw efficiency of 24.3 watt-hours per mile, which translates to over 1000 miles per gallon," he said. By our math, that's 1387 MPGe. For some added context, the EPA rates the 9000-plus-pound GMC Hummer EV pickup at 45 MPGe on the highway.
He may have been selling it short, an online convertor showed it closer to 1400 miles per gallon. Go sunlight!
The Sun Strider team set up the Cannonball Sun as an open competition and hopes that others will take up the challenge to beat their time. The only rules are that the vehicle be powered only by the sun, registered, and follow all rules of the road. There is talk of heading to Alaska next summer to take advantage of the near-constant daylight. Or maybe they'll tackle the Pan American Highway. Better them than me.
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