As you might suspect, a drive of this length on normal roads required a big battery pack. The total pack capacity was 108 kWh, thanks to the combination of the built-in 86-kWh pack that uses lithium polymer cells from Kokam and a 130-pound, 22-kWh external pack that Metron has developed that can charge the built-in pack while driving.
The average speed of the 500-mile journey was 45 miles per hour (72 kilometers per hour) through rural countryside, towns, and some time on the highway. The drivers –Andrej and Jasna Pecjak – did not use air conditioning, but the fans were running. The weather was temperate enough that AC wasn't needed anyway these last two days.
The Metron 7 was a part of the last two WAVE events and has been updated since the last record was set in October 2014. On the new record journey, the minivan was loaded up with gear, but the Metron engineers made improvements to the car in the last eight months: the side mirrors are smaller and they fitted a better aerodynamic cover underneath the vehicle, for example. Andrej said that the cost for the batteries was around $50,000, since some of the cells he got were used.
Today's record is unofficial, but AutoblogGreen witnessed both the sealing of the charge port in Berlin and was in the car for the last 125 kilometers today.