With a wingspan bigger than a Boeing 747, but weighing only a little more than a car, the Solar Impulse 2 team announced Wednesday their attempt to complete the first round-the-world solar flight will be delayed until 2016.

The announcement came after the completion of a record breaking oceanic flight from Nagoya, Japan to Kalaeloa, Hawaii, which lasted a total of 117 hrs and 52 mins. In a post on their Website, the team called the trip “the longest and most difficult leg” of the journey. The plane’s average ground speed during the leg was around 38 mph.  

While the flight was a success, the trip came at a cost. “The cost is that we overheated the batteries during the first day of flight,” said Bertrand Piccard, the founder and pilot of the aircraft, in a video.

Piccard said the battery temperature increase was due to a high climb rate and over insulation. “There was no way to decrease the temperature for the remaining duration as each daily cycle requires an ascent to (28,000 ft) and descent for optimal energy management,” according to the team.

The plane’s 17,248 solar cells supply four electric motors with energy. Additionally, the cells recharge four 70-L lithium polymer batteries.

“The flight around the world will continue next April,” Piccard said, noting that the trip will take two years rather than one.  

According to the Solar Impulse team, the project took 12 years of work, including a feasibility study, concept, design and construction; 50 engineers and technicians; 80 technological partners; more than 100 advisers and suppliers; a prototype; and a final aircraft.

Piccard, who achieved the first round-the-world nonstop balloon flight, teamed with André Borschberg, an engineer and pilot, for the Solar Impulse venture.

The flight to Hawaii was their eighth in a planned 13-flight expedition. The Solar Impulse 2 began its journey the morning of March 9, taking off from Abu Dhabi.

Thanks to the Univ. of Hawaii and the Department of Transportation the plane will remain at a hangar at the Kalaeloa Airport.

Piccard and Borschberg have started a Future Is Clean initiative with the goal of halving the world’s energy consumption by using clean technologies while creating jobs, profits and sustainable growth.

The Future Is Clean community will address the United Nations Climate Change Conference, held in Paris in December.

“I really hope that the supporters will continue to support the Future Is Clean initiative and continue to collect millions of voice in favor of clean technologies,” said Piccard. “So even if Solar Impulse doesn’t fly, the spirit of Solar Impulse and the reason why we’re doing it can fly.”