Well depending on when this happens if so during day you can turn off the lights that are needed also you can turn off comms again depending i have been told if in controlled you tell them the situation and call them using phone, umm a big user of power is the Transponder so if in a uncontrolled area you could turn that off as well so in order it can be Lights, wait if you have any other electrical equiptment in the aircraft like Nav, GPS etc it can be switched off so it can be lights,other electrical equp umm comms and Transponder hmm yeah lol i think i would do that.