No. Any charging senario will not harm iPhone 5 battery. iPhone 5 has Lithium battery so you are able to charge it any time which is convenient for you. Most users charge at night while they sleep so the battery is fully charged ready for the day. Also you can leave the iPhone 5 on charger all day if you want, the charging system of iPhone 5 shuts off when the battery is fully charged, so the iPhone battery will not overcharge.