Both cars have the same 85 KWh battery pack, but the ‘P” stands for performance. The added performance package draws more energy from the battery pack and can reduce the range. The EPA-rated range of a 85D is 270 miles, while the P85D’s EPA-rated range stands at 253 miles.
To get so much range out of the car, Spencer drove at ~22 mph. The practice is called “hypermiling” and the goal is to get the most out of a vehicle’s energy potential.
Spencer took everything into consideration including weight. He carried in the vehicle only a laptop with extra batteries to stream the attempt at breaking the record, some granola bars, water bottles and two independently powered fans since he wouldn’t use the AC in order to limit energy consumption.
He even slightly over-inflated the tires by 5 psi in order to gain some efficiency.
Spencer attempted to live stream the event on Youtube, but due network connection issues and laptop battery problems, the stream failed, but the attempt surpassed any expectations. You can watch Casey setting up to leave for his attempt in this video: