University of Texas Solar Vehicles Team

UT's first solar car was Texas Native Sun, built with a graphite and epoxy composite monocoque body, 1,000 solar cells, and 66 nickel-hydrogen batteries.[3] A 2 hp (1.5 kW) high-density permanent magnet electric motor powered its continuously variable transmission.[4] The teardrop-shaped car's length, width, and height were 19 by 6.5 by 5 feet (5.8 m × 2.0 m × 1.5 m), and it weighed 320 pounds (150 kg). Its top speed was 65 mph. Project advisors included professors Gary Vliet and Ron Matthews.[5]

It competed in three races—Sunrayce 1990 (placed 22nd out of 32),[6] Sunrayce 1993,[7] and the California Clean Air Race 1991 where it placed second out of 30 teams.[8]

UT's second solar car, Texas Native Sun II, was a two-seater and larger than the first, weighing 1,000 lb (450 kg).[9] It featured a bespoke electric hub motor and controller supplied by lead-acid batteries.[10] Texas Native Sun II raced in the Tour de Sol in 1996 placing fourth in its class.[8][11]

The team's third solar car was named Solstice,[11][9] which was built for Sunrayce 1999 but never completed.[12]

With construction beginning in 2004, Solar Steer was UT's first vehicle to have lithium-ion batteries and a carbon fiber body.[8] It was completed in 2005 at a cost of $90,000. The solar array is made of 600 photovoltaic cells grouped in modules of 50, and split into three subarrays, for a total area of 8 m² (86 sq ft).[13] A maximum power output of 1,200 W (1.6 hp) could propel it to a cruising speed of 45 mph (72 km/h) and top speed of 55 mph (89 km/h).[14]

It was entered in the 2005 North American Solar Challenge but could not compete due to poor weather and a steering malfunction.[8][11] The team also entered Solar Steer into the North American Solar Challenge for 2006.[15]

Samsung Solorean

Design began in early 2007 for UTSVT's next car, to be named after their sponsor, Samsung, and the DeLorean in Back to the Future. The chassis is chromoly tubular steel supporting the carbon fiber body. The battery pack consists of 598 LG 18650 lithium ion cells.[3] The solar array is an assembly of 393 SunPower A-300 monocrystalline silicon cells split into three arrays able to produce up to 1.21 kW (1.62 hp).[15][3] A National Instruments CompactRIO controls all electrical subsystems.[11] The motor is a New Generation brushless permanent magnet motor that can provide 3.75 kW (5.03 hp) of power at 95% efficiency while weighing 20 kg (44 lb).

UTSVT completed Solorean June 2008, just too late to compete in the North American Solar Challenge that summer. Samsung Solorean competed in the 2009 and 2010 FSGP and 2010 American Solar Challenge.[16][17]

TexSun was completed spring 2013 at a cost of $140,000,[18] $50,000 of which was donated by Circuit of the Americas.[19] The three-wheeled vehicle has an aluminum space-frame chassis, carbon fiber body, and uses an Enertrac 602 hub motor to power the rear wheel. The batteries are lithium iron phosphate.[20] It weighs between 500 and 600 lb (230–270 kg).[21] The solar panels, mounted to a carbon-kevlar wing, provide a maximum of 1,300 W (1.7 hp).[19] The car has a theoretical top speed of 60 to 70 mph (97–113 km/h).[21]

TexSun placed sixth at the 2013 Formula Sun Grand Prix held at Circuit of the Americas for the first time.[1][22] It also participated in the 2015 and 2016 FSGPs, and competed for the last time at the 2017 FSGP the team hosted.[8]

Production of BeVolt (portmanteau of Bevo and volt)[2] began in the spring semester of 2017 to be race-ready for Formula Sun Grand Prix 2018.[23] UTSVT again targeted summer 2019 for completion.[24] The planned specifications for the car include a 4.8 kWh lithium ion battery, a 4 m² (43 sq ft) solar array producing 985 W (1.321 hp), and two DC hub motors together good for 2 kW (2.7 hp). The team designed for a weight of 160 kg (350 lb) for BeVolt by using a carbon fiber monocoque chassis and kevlar solar wing.[25] This car fell behind schedule and was ultimately cancelled in 2020 following multiple manufacturing difficulties and the COVID-19 pandemic. BeVolt was budgeted at $180,000.[18]

Planning of a new car began during the fall 2020 semester, with a goal to race during 2022. UTSVT designed their latest car, Lonestar, to weigh 600 lb (270 kg) and have a solar array of 260 cells that produces 875 W (1.173 hp). Design work, finished in December 2020, was done predominantly virtually, with students spread far due to the COVID-19 pandemic. This also impacted manufacturing due to limited hours at J. J. Pickle Research Campus and some team members still working remotely.[26]

The team brought Lonestar to the 2022 FSGP but could not race after technical inspection revealed an issue with the battery management system. The team will utilize the car as a test bed for the next car's development, which started summer 2022.[27]

After Lonestar was found to have disqualifying issues, Project X was started in the summer of 2022. This vehicle is currently in development, is expected to complete by June 2024, and will be given its official name when unveiled. It will compete both in the FSGP and ASC races that year.[28]