The pilots of a grounded solar-powered plane say they put too much stress on the batteries of their aircraft as they were leaving Japan for a five-day record-breaking flight to Hawaii.
The pilots then discovered they had too much insulation around the batteries for them to adequately cool down during the flight through tropical skies.
The team is grounding the plane in Hawaii while it replaces the batteries, which were damaged from overheating. The pilots plan to resume their round-the-world voyage in April.
Solar Impulse 2 pilot Andre Borschberg said Wednesday the airplane had to make a very steep climb and then steep descent after taking off from Nagoya, Japan, to comply with Japanese flight restrictions.
He says this stressed the batteries.