In 2017, Vattenfall (then Nuon) Solar Team in their car Nuna8S set a solar racing endurance record at the RDW (Netherlands Vehicle Authority) test track in Lelystad, NL of 882 km in 12 hours or 73.5 km/h (see Dutch video here).
On Saturday 8 August this year they hope to break their own record in the Nuna Phoenix which they originally intended to race at the now-cancelled American Solar Challenge (this car is, I understand, Nuna9S with a variety of changes made specifically for ASC, including a metal roll cage and a motor suitable for climbing mountains).
According to media reports, they will begin with a full battery, but then run only on solar power for the next 12 hours (this is in contrast to the 24-hour European Solar Challenge, where two recharges are permitted during the night). For their event, Vattenfall Solar Team will have four drivers, each taking on a 3-hour stint (Marloes Nanninga, Maxime Croft, Sylke van der Kleij, and Mees van Vliet). Nuna Phoenix will begin driving at around 7:00 local time. I understand from live streams that they are also water-cooling the panel at driver changes.
Edit 1: This 12-hour endurance event also includes the first public reveal of Nuna Phoenix. The event has now begun.
Edit 2: Nuna Phoenix has clocked up approximately 126 km in 90 minutes so far (84 km/h).
Edit 3: Now it’s approximately 238 km in 3 hours (79.3 km/h).
Edit 4: Nuna Phoenix has now clocked up 355 km in 285 minutes (74.7 km/h, which suggests that they are being cautious about possible clouds coming in).
Edit 5: Now it’s approximately 538 km in 7 hours (76.9 km/h).
Edit 6: At the last driver change (9 hours) it’s 670 km (74.4 km/h).
Edit 7: After 12 hours, Vattenfall Solar Team have indeed set a new world record of 924 km (77 km/h), following a late sprint (reaching at least 97 km/h). Well done!
For teams interested in challenging this record, my proposal would be that the format used by Vattenfall Solar Team be followed, in a car designed for (and ideally, having passed scrutineering in) either WSC, ASC, or SSC within the previous 3 years (I exclude ESC from that list, because of its different format). Not that many teams have a car as fast as Nuna Phoenix, of course!