How to force Apple iPhone to work more days without recharge. It is necessary to include only one control

This August was given rich in travel: I spent some days with tent in the woods situated near Moscow, went to Kaliningrad and after that visited the four-day Signal Festival in Nicol Idler to Kaluga Region. It is clear that Apple iPhone with help a paverbanka which came to an end too quickly was necessary to load the most part of time. So few times was so that I remained in the distance...