I dont think that two laps or more will happen. For the weight of the batterys, it would be like swaping an engine in a petrol bike. Mugen said at the TT this year that were were not going to practice the day before the race as the batterys need to cool down for 24hrs before accepting a full charge. ( generally btterys need to be charge cold, and discharged warm) The cost for a replacement battery pack would be prohibative for the smaller teams resulting in an even smaller grid.
MotoCzysz were tweeting something about them wanting to do it a few days ago.