On Sunday, 27 December 2015 19:33:58 UTC+2, wrote:

A search for "Interview with Jerzy Peszke 30 January 2015" gets an interview where Peszke says that the batteries weigh 20 kg (versus 32 kg for the FES). Of course, it is not clear how the GP 14 gets the same range as a FES glider like the Silent Electro 2, yet has batteries that weigh only 2/3 as much.

FES installations use total of 4,2 kWh battery capacity with mass of 30+ kg.. GP states it has 4 kWh battery capacity. To get that from 20 kg commercially available battery would be nothing short of sensational.